general protection fault in usb_set_interface

33 views
Skip to first unread message

syzbot

unread,
Sep 16, 2019, 9:29:11 AM9/16/19
to andre...@google.com, gre...@linuxfoundation.org, kai.he...@canonical.com, linux-...@vger.kernel.org, linu...@vger.kernel.org, ma...@mansr.com, one...@suse.com, st...@rowland.harvard.edu, syzkall...@googlegroups.com
Hello,

syzbot found the following crash on:

HEAD commit: f0df5c1b usb-fuzzer: main usb gadget fuzzer driver
git tree: https://github.com/google/kasan.git usb-fuzzer
console output: https://syzkaller.appspot.com/x/log.txt?x=158b66f1600000
kernel config: https://syzkaller.appspot.com/x/.config?x=5c6633fa4ed00be5
dashboard link: https://syzkaller.appspot.com/bug?extid=7fa38a608b1075dfd634
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=14f57db9600000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=127b61a5600000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+7fa38a...@syzkaller.appspotmail.com

usb 3-1: usbvision_write_reg: failed: error -2
usbvision_set_audio: can't write iopin register for audio switching
kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] SMP KASAN
CPU: 1 PID: 1955 Comm: v4l_id Not tainted 5.3.0-rc7+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
RIP: 0010:usb_set_interface+0x34/0xa50 drivers/usb/core/message.c:1362
Code: fc 55 53 48 83 ec 40 89 54 24 18 89 74 24 10 e8 22 1c ef fd 49 8d 7c
24 48 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f
85 fb 08 00 00 49 8b 44 24 48 49 8d 7c 24 18 48 89
RSP: 0018:ffff8881cb19fd50 EFLAGS: 00010206
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000009 RSI: ffffffff834ebe7e RDI: 0000000000000048
RBP: ffff8881cb8e4200 R08: ffffffff88d21878 R09: ffffed103971cb43
R10: ffff8881cb19fdc8 R11: ffff8881cb8e5a17 R12: 0000000000000000
R13: ffff8881cb8e5a10 R14: ffff8881cb8e4cc8 R15: ffff8881cb8e5178
FS: 00007f4f60b6d700(0000) GS:ffff8881db300000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f4f6060c330 CR3: 00000001cc3a8000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
usbvision_radio_close+0x105/0x250
drivers/media/usb/usbvision/usbvision-video.c:1114
v4l2_release+0x2e7/0x390 drivers/media/v4l2-core/v4l2-dev.c:455
__fput+0x2d7/0x840 fs/file_table.c:280
task_work_run+0x13f/0x1c0 kernel/task_work.c:113
tracehook_notify_resume include/linux/tracehook.h:188 [inline]
exit_to_usermode_loop+0x1d2/0x200 arch/x86/entry/common.c:163
prepare_exit_to_usermode arch/x86/entry/common.c:194 [inline]
syscall_return_slowpath arch/x86/entry/common.c:274 [inline]
do_syscall_64+0x45f/0x580 arch/x86/entry/common.c:299
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7f4f6069b2b0
Code: 40 75 0b 31 c0 48 83 c4 08 e9 0c ff ff ff 48 8d 3d c5 32 08 00 e8 c0
07 02 00 83 3d 45 a3 2b 00 00 75 10 b8 03 00 00 00 0f 05 <48> 3d 01 f0 ff
ff 73 31 c3 48 83 ec 08 e8 ce 8a 01 00 48 89 04 24
RSP: 002b:00007ffde2d50ee8 EFLAGS: 00000246 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000003 RCX: 00007f4f6069b2b0
RDX: 00007f4f60951df0 RSI: 0000000000000001 RDI: 0000000000000003
RBP: 0000000000000000 R08: 00007f4f60951df0 R09: 000000000000000a
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000400884
R13: 00007ffde2d51040 R14: 0000000000000000 R15: 0000000000000000
Modules linked in:
---[ end trace 62bd2b7512ab49ee ]---
RIP: 0010:usb_set_interface+0x34/0xa50 drivers/usb/core/message.c:1362
Code: fc 55 53 48 83 ec 40 89 54 24 18 89 74 24 10 e8 22 1c ef fd 49 8d 7c
24 48 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f
85 fb 08 00 00 49 8b 44 24 48 49 8d 7c 24 18 48 89
RSP: 0018:ffff8881cb19fd50 EFLAGS: 00010206
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000009 RSI: ffffffff834ebe7e RDI: 0000000000000048
RBP: ffff8881cb8e4200 R08: ffffffff88d21878 R09: ffffed103971cb43
R10: ffff8881cb19fdc8 R11: ffff8881cb8e5a17 R12: 0000000000000000
R13: ffff8881cb8e5a10 R14: ffff8881cb8e4cc8 R15: ffff8881cb8e5178
FS: 00007f4f60b6d700(0000) GS:ffff8881db300000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f4f6060c330 CR3: 00000001cc3a8000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


---
This bug is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.

syzbot will keep track of this bug report. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
syzbot can test patches for this bug, for details see:
https://goo.gl/tpsmEJ#testing-patches

Alan Stern

unread,
Sep 16, 2019, 4:51:44 PM9/16/19
to syzbot, andre...@google.com, gre...@linuxfoundation.org, kai.he...@canonical.com, linux-...@vger.kernel.org, linu...@vger.kernel.org, ma...@mansr.com, one...@suse.com, syzkall...@googlegroups.com
Use-after-free bug.

Alan Stern

#syz test: https://github.com/google/kasan.git f0df5c1b

drivers/media/usb/usbvision/usbvision-video.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

Index: usb-devel/drivers/media/usb/usbvision/usbvision-video.c
===================================================================
--- usb-devel.orig/drivers/media/usb/usbvision/usbvision-video.c
+++ usb-devel/drivers/media/usb/usbvision/usbvision-video.c
@@ -1111,7 +1111,8 @@ static int usbvision_radio_close(struct
mutex_lock(&usbvision->v4l2_lock);
/* Set packet size to 0 */
usbvision->iface_alt = 0;
- usb_set_interface(usbvision->dev, usbvision->iface,
+ if (usbvision->dev)
+ usb_set_interface(usbvision->dev, usbvision->iface,
usbvision->iface_alt);

usbvision_audio_off(usbvision);

syzbot

unread,
Sep 16, 2019, 5:03:02 PM9/16/19
to andre...@google.com, gre...@linuxfoundation.org, kai.he...@canonical.com, linux-...@vger.kernel.org, linu...@vger.kernel.org, ma...@mansr.com, one...@suse.com, st...@rowland.harvard.edu, syzkall...@googlegroups.com
Hello,

syzbot has tested the proposed patch but the reproducer still triggered
crash:
general protection fault in vidioc_querycap

kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] SMP KASAN
CPU: 0 PID: 2937 Comm: v4l_id Not tainted 5.3.0-rc7+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
RIP: 0010:usb_make_path include/linux/usb.h:914 [inline]
RIP: 0010:vidioc_querycap+0x11c/0x320
drivers/media/usb/usbvision/usbvision-video.c:460
Code: 80 3c 02 00 0f 85 03 02 00 00 4c 8b ad f0 17 00 00 48 b8 00 00 00 00
00 fc ff df 49 8d 7d 48 4d 8d 45 04 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f
85 c7 01 00 00 48 b8 00 00 00 00 00 fc ff df 4d 8b
RSP: 0018:ffff8881c045fa28 EFLAGS: 00010206
RAX: dffffc0000000000 RBX: ffff8881c045fc18 RCX: 0000000000000000
RDX: 0000000000000009 RSI: 2e4c1f4252534d27 RDI: 0000000000000048
RBP: ffff8881d5172100 R08: 0000000000000004 R09: fffffbfff0c90220
R10: fffffbfff0c9021f R11: ffffffff864810f8 R12: ffff8881d517399c
R13: 0000000000000000 R14: ffff8881c045fc48 R15: 0000000080050000
FS: 00007fd17db9e700(0000) GS:ffff8881db200000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f28e2972518 CR3: 00000001d9a2b000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
v4l_querycap+0x121/0x340 drivers/media/v4l2-core/v4l2-ioctl.c:1058
__video_do_ioctl+0x969/0xba0 drivers/media/v4l2-core/v4l2-ioctl.c:2878
video_usercopy+0x446/0xf40 drivers/media/v4l2-core/v4l2-ioctl.c:3060
v4l2_ioctl+0x1a2/0x220 drivers/media/v4l2-core/v4l2-dev.c:360
vfs_ioctl fs/ioctl.c:46 [inline]
file_ioctl fs/ioctl.c:509 [inline]
do_vfs_ioctl+0xd2d/0x1330 fs/ioctl.c:696
ksys_ioctl+0x9b/0xc0 fs/ioctl.c:713
__do_sys_ioctl fs/ioctl.c:720 [inline]
__se_sys_ioctl fs/ioctl.c:718 [inline]
__x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:718
do_syscall_64+0xb7/0x580 arch/x86/entry/common.c:296
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7fd17d6d1347
Code: 90 90 90 48 8b 05 f1 fa 2a 00 64 c7 00 26 00 00 00 48 c7 c0 ff ff ff
ff c3 90 90 90 90 90 90 90 90 90 90 b8 10 00 00 00 0f 05 <48> 3d 01 f0 ff
ff 73 01 c3 48 8b 0d c1 fa 2a 00 31 d2 48 29 c2 64
RSP: 002b:00007ffd9397d098 EFLAGS: 00000202 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007fd17d6d1347
RDX: 00007ffd9397d0a0 RSI: 0000000080685600 RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000400884
R13: 00007ffd9397d1f0 R14: 0000000000000000 R15: 0000000000000000
Modules linked in:
---[ end trace e95ba987ba08e9f8 ]---
RIP: 0010:usb_make_path include/linux/usb.h:914 [inline]
RIP: 0010:vidioc_querycap+0x11c/0x320
drivers/media/usb/usbvision/usbvision-video.c:460
Code: 80 3c 02 00 0f 85 03 02 00 00 4c 8b ad f0 17 00 00 48 b8 00 00 00 00
00 fc ff df 49 8d 7d 48 4d 8d 45 04 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f
85 c7 01 00 00 48 b8 00 00 00 00 00 fc ff df 4d 8b
RSP: 0018:ffff8881c045fa28 EFLAGS: 00010206
RAX: dffffc0000000000 RBX: ffff8881c045fc18 RCX: 0000000000000000
RDX: 0000000000000009 RSI: 2e4c1f4252534d27 RDI: 0000000000000048
RBP: ffff8881d5172100 R08: 0000000000000004 R09: fffffbfff0c90220
R10: fffffbfff0c9021f R11: ffffffff864810f8 R12: ffff8881d517399c
R13: 0000000000000000 R14: ffff8881c045fc48 R15: 0000000080050000
FS: 00007fd17db9e700(0000) GS:ffff8881db200000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f28e2972518 CR3: 00000001d9a2b000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


Tested on:

commit: f0df5c1b usb-fuzzer: main usb gadget fuzzer driver
git tree: https://github.com/google/kasan.git
console output: https://syzkaller.appspot.com/x/log.txt?x=12a52ac9600000
kernel config: https://syzkaller.appspot.com/x/.config?x=5c6633fa4ed00be5
dashboard link: https://syzkaller.appspot.com/bug?extid=7fa38a608b1075dfd634
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
patch: https://syzkaller.appspot.com/x/patch.diff?x=14e7f9c3600000

Hillf Danton

unread,
Sep 17, 2019, 3:03:01 AM9/17/19
to syzbot, andre...@google.com, gre...@linuxfoundation.org, kai.he...@canonical.com, linux-...@vger.kernel.org, linu...@vger.kernel.org, ma...@mansr.com, one...@suse.com, st...@rowland.harvard.edu, syzkall...@googlegroups.com

On Mon, 16 Sep 2019 06:29:09 -0700
>
> syzbot found the following crash on:
>
> HEAD commit: f0df5c1b usb-fuzzer: main usb gadget fuzzer driver
> git tree: https://github.com/google/kasan.git usb-fuzzer
> console output: https://syzkaller.appspot.com/x/log.txt?x=158b66f1600000
> kernel config: https://syzkaller.appspot.com/x/.config?x=5c6633fa4ed00be5
> dashboard link: https://syzkaller.appspot.com/bug?extid=7fa38a608b1075dfd634
> compiler: gcc (GCC) 9.0.0 20181231 (experimental)
> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=14f57db9600000
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=127b61a5600000
>
> IMPORTANT: if you fix the bug, please add the following tag to the commit:
> Reported-by: syzbot+7fa38a...@syzkaller.appspotmail.com
>
> usb 3-1: usbvision_write_reg: failed: error -2
> usbvision_set_audio: can't write iopin register for audio switching
> kasan: CONFIG_KASAN_INLINE enabled
> kasan: GPF could be caused by NULL-ptr deref or user memory access
> general protection fault: 0000 [#1] SMP KASAN
> CPU: 1 PID: 1955 Comm: v4l_id Not tainted 5.3.0-rc7+ #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
> Google 01/01/2011
> RIP: 0010:usb_set_interface+0x34/0xa50 drivers/usb/core/message.c:1362
> Code: fc 55 53 48 83 ec 40 89 54 24 18 89 74 24 10 e8 22 1c ef fd 49 8d 7c
> 24 48 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f
> 85 fb 08 00 00 49 8b 44 24 48 49 8d 7c 24 18 48 89
> RSP: 0018:ffff8881cb19fd50 EFLAGS: 00010206
> RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000000
> RDX: 0000000000000009 RSI: ffffffff834ebe7e RDI: 0000000000000048
> RBP: ffff8881cb8e4200 R08: ffffffff88d21878 R09: ffffed103971cb43
> R10: ffff8881cb19fdc8 R11: ffff8881cb8e5a17 R12: 0000000000000000
> R13: ffff8881cb8e5a10 R14: ffff8881cb8e4cc8 R15: ffff8881cb8e5178
> FS: 00007f4f60b6d700(0000) GS:ffff8881db300000(0000) knlGS:0000000000000000
> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00007f4f6060c330 CR3: 00000001cc3a8000 CR4: 00000000001406e0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> Call Trace:
> usbvision_radio_close+0x105/0x250 drivers/media/usb/usbvision/usbvision-video.c:1114
> v4l2_release+0x2e7/0x390 drivers/media/v4l2-core/v4l2-dev.c:455
> __fput+0x2d7/0x840 fs/file_table.c:280
> task_work_run+0x13f/0x1c0 kernel/task_work.c:113
> tracehook_notify_resume include/linux/tracehook.h:188 [inline]
> exit_to_usermode_loop+0x1d2/0x200 arch/x86/entry/common.c:163
> prepare_exit_to_usermode arch/x86/entry/common.c:194 [inline]
> syscall_return_slowpath arch/x86/entry/common.c:274 [inline]
> do_syscall_64+0x45f/0x580 arch/x86/entry/common.c:299
> entry_SYSCALL_64_after_hwframe+0x49/0xbe

Fix 0c0d06cac63e

--- a/drivers/media/usb/usbvision/usbvision-video.c
+++ b/drivers/media/usb/usbvision/usbvision-video.c
@@ -395,6 +395,8 @@ static int usbvision_v4l2_close(struct f

if (usbvision->remove_pending) {
printk(KERN_INFO "%s: Final disconnect\n", __func__);
+ usb_put_dev(usbvision->dev);
+ v4l2_fh_release(file);
usbvision_release(usbvision);
return 0;
}
@@ -1121,6 +1123,7 @@ static int usbvision_radio_close(struct

if (usbvision->remove_pending) {
printk(KERN_INFO "%s: Final disconnect\n", __func__);
+ usb_put_dev(usbvision->dev);
v4l2_fh_release(file);
usbvision_release(usbvision);
return 0;
@@ -1568,9 +1571,6 @@ static void usbvision_disconnect(struct
usbvision_i2c_unregister(usbvision);
usbvision->remove_pending = 1; /* Now all ISO data will be ignored */

- usb_put_dev(usbvision->dev);
- usbvision->dev = NULL; /* USB device is no more */
-
mutex_unlock(&usbvision->v4l2_lock);

if (usbvision->user) {
@@ -1579,6 +1579,7 @@ static void usbvision_disconnect(struct
wake_up_interruptible(&usbvision->wait_frame);
wake_up_interruptible(&usbvision->wait_stream);
} else {
+ usb_put_dev(usbvision->dev);
usbvision_release(usbvision);
}


Alan Stern

unread,
Sep 17, 2019, 11:16:33 AM9/17/19
to syzbot, andre...@google.com, gre...@linuxfoundation.org, kai.he...@canonical.com, linux-...@vger.kernel.org, linu...@vger.kernel.org, ma...@mansr.com, one...@suse.com, syzkall...@googlegroups.com
On Mon, 16 Sep 2019, syzbot wrote:

> Hello,
>
> syzbot has tested the proposed patch but the reproducer still triggered
> crash:
> general protection fault in vidioc_querycap

Same problem in a different part of the code.

Alan Stern

#syz test: https://github.com/google/kasan.git f0df5c1b

drivers/media/usb/usbvision/usbvision-video.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)

Index: usb-devel/drivers/media/usb/usbvision/usbvision-video.c
===================================================================
--- usb-devel.orig/drivers/media/usb/usbvision/usbvision-video.c
+++ usb-devel/drivers/media/usb/usbvision/usbvision-video.c
@@ -453,6 +453,12 @@ static int vidioc_querycap(struct file *
{
struct usb_usbvision *usbvision = video_drvdata(file);

+ mutex_lock(&usbvision->v4l2_lock);
+ if (!usbvision->dev) {
+ mutex_unlock(&usbvision->v4l2_lock);
+ return -ENODEV;
+ }
+
strscpy(vc->driver, "USBVision", sizeof(vc->driver));
strscpy(vc->card,
usbvision_device_data[usbvision->dev_model].model_string,
@@ -464,6 +470,7 @@ static int vidioc_querycap(struct file *
vc->capabilities |= V4L2_CAP_RADIO;
if (usbvision->have_tuner)
vc->capabilities |= V4L2_CAP_TUNER;
+ mutex_unlock(&usbvision->v4l2_lock);
return 0;
}

@@ -1111,7 +1118,8 @@ static int usbvision_radio_close(struct

syzbot

unread,
Sep 17, 2019, 11:28:02 AM9/17/19
to andre...@google.com, gre...@linuxfoundation.org, kai.he...@canonical.com, linux-...@vger.kernel.org, linu...@vger.kernel.org, ma...@mansr.com, one...@suse.com, st...@rowland.harvard.edu, syzkall...@googlegroups.com
Hello,

syzbot has tested the proposed patch but the reproducer still triggered
crash:
possible deadlock in vidioc_querycap

============================================
WARNING: possible recursive locking detected
5.3.0-rc7+ #0 Not tainted
--------------------------------------------
v4l_id/3016 is trying to acquire lock:
0000000069c3004e (&usbvision->v4l2_lock){+.+.}, at:
vidioc_querycap+0x62/0x3b0 drivers/media/usb/usbvision/usbvision-video.c:456

but task is already holding lock:
0000000069c3004e (&usbvision->v4l2_lock){+.+.}, at:
__video_do_ioctl+0x3ba/0xba0 drivers/media/v4l2-core/v4l2-ioctl.c:2846

other info that might help us debug this:
Possible unsafe locking scenario:

CPU0
----
lock(&usbvision->v4l2_lock);
lock(&usbvision->v4l2_lock);

*** DEADLOCK ***

May be due to missing lock nesting notation

1 lock held by v4l_id/3016:
#0: 0000000069c3004e (&usbvision->v4l2_lock){+.+.}, at:
__video_do_ioctl+0x3ba/0xba0 drivers/media/v4l2-core/v4l2-ioctl.c:2846

stack backtrace:
CPU: 0 PID: 3016 Comm: v4l_id Not tainted 5.3.0-rc7+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0xca/0x13e lib/dump_stack.c:113
print_deadlock_bug kernel/locking/lockdep.c:2301 [inline]
check_deadlock kernel/locking/lockdep.c:2342 [inline]
validate_chain kernel/locking/lockdep.c:2881 [inline]
__lock_acquire.cold+0x148/0x29b kernel/locking/lockdep.c:3880
lock_acquire+0x127/0x320 kernel/locking/lockdep.c:4412
__mutex_lock_common kernel/locking/mutex.c:930 [inline]
__mutex_lock+0x158/0x1360 kernel/locking/mutex.c:1077
vidioc_querycap+0x62/0x3b0
drivers/media/usb/usbvision/usbvision-video.c:456
v4l_querycap+0x121/0x340 drivers/media/v4l2-core/v4l2-ioctl.c:1058
__video_do_ioctl+0x969/0xba0 drivers/media/v4l2-core/v4l2-ioctl.c:2878
video_usercopy+0x446/0xf40 drivers/media/v4l2-core/v4l2-ioctl.c:3060
v4l2_ioctl+0x1a2/0x220 drivers/media/v4l2-core/v4l2-dev.c:360
vfs_ioctl fs/ioctl.c:46 [inline]
file_ioctl fs/ioctl.c:509 [inline]
do_vfs_ioctl+0xd2d/0x1330 fs/ioctl.c:696
ksys_ioctl+0x9b/0xc0 fs/ioctl.c:713
__do_sys_ioctl fs/ioctl.c:720 [inline]
__se_sys_ioctl fs/ioctl.c:718 [inline]
__x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:718
do_syscall_64+0xb7/0x580 arch/x86/entry/common.c:296
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7f642b0b9347
Code: 90 90 90 48 8b 05 f1 fa 2a 00 64 c7 00 26 00 00 00 48 c7 c0 ff ff ff
ff c3 90 90 90 90 90 90 90 90 90 90 b8 10 00 00 00 0f 05 <48> 3d 01 f0 ff
ff 73 01 c3 48 8b 0d c1 fa 2a 00 31 d2 48 29 c2 64
RSP: 002b:00007ffc2fc62b28 EFLAGS: 00000206 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f642b0b9347
RDX: 00007ffc2fc62b30 RSI: 0000000080685600 RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000400884
R13: 00007ffc2fc62c80 R14: 0000000000000000 R15: 0000000000000000


Tested on:

commit: f0df5c1b usb-fuzzer: main usb gadget fuzzer driver
git tree: https://github.com/google/kasan.git
console output: https://syzkaller.appspot.com/x/log.txt?x=160d95c3600000
kernel config: https://syzkaller.appspot.com/x/.config?x=5c6633fa4ed00be5
dashboard link: https://syzkaller.appspot.com/bug?extid=7fa38a608b1075dfd634
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
patch: https://syzkaller.appspot.com/x/patch.diff?x=125290b1600000

Alan Stern

unread,
Sep 17, 2019, 11:54:01 AM9/17/19
to syzbot, andre...@google.com, gre...@linuxfoundation.org, kai.he...@canonical.com, linux-...@vger.kernel.org, linu...@vger.kernel.org, ma...@mansr.com, one...@suse.com, syzkall...@googlegroups.com
On Tue, 17 Sep 2019, syzbot wrote:

> Hello,
>
> syzbot has tested the proposed patch but the reproducer still triggered
> crash:
> possible deadlock in vidioc_querycap
>
> ============================================
> WARNING: possible recursive locking detected
> 5.3.0-rc7+ #0 Not tainted
> --------------------------------------------
> v4l_id/3016 is trying to acquire lock:
> 0000000069c3004e (&usbvision->v4l2_lock){+.+.}, at:
> vidioc_querycap+0x62/0x3b0 drivers/media/usb/usbvision/usbvision-video.c:456
>
> but task is already holding lock:
> 0000000069c3004e (&usbvision->v4l2_lock){+.+.}, at:
> __video_do_ioctl+0x3ba/0xba0 drivers/media/v4l2-core/v4l2-ioctl.c:2846

Heh. That's what comes of trying to patch a driver when you aren't an
expert on it already.

Okay, the lock is already held at this point so we don't need to
acquire it.

Alan Stern

#syz test: https://github.com/google/kasan.git f0df5c1b

drivers/media/usb/usbvision/usbvision-video.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)

Index: usb-devel/drivers/media/usb/usbvision/usbvision-video.c
===================================================================
--- usb-devel.orig/drivers/media/usb/usbvision/usbvision-video.c
+++ usb-devel/drivers/media/usb/usbvision/usbvision-video.c
@@ -453,6 +453,9 @@ static int vidioc_querycap(struct file *
{
struct usb_usbvision *usbvision = video_drvdata(file);

+ if (!usbvision->dev)
+ return -ENODEV;
+
strscpy(vc->driver, "USBVision", sizeof(vc->driver));
strscpy(vc->card,
usbvision_device_data[usbvision->dev_model].model_string,
@@ -1111,7 +1114,8 @@ static int usbvision_radio_close(struct

syzbot

unread,
Sep 17, 2019, 12:06:02 PM9/17/19
to andre...@google.com, gre...@linuxfoundation.org, kai.he...@canonical.com, linux-...@vger.kernel.org, linu...@vger.kernel.org, ma...@mansr.com, one...@suse.com, st...@rowland.harvard.edu, syzkall...@googlegroups.com
Hello,

syzbot has tested the proposed patch but the reproducer still triggered
crash:
WARNING in sysfs_remove_group

------------[ cut here ]------------
sysfs group 'power' not found for kobject 'radio3'
WARNING: CPU: 1 PID: 2883 at fs/sysfs/group.c:278 sysfs_remove_group
fs/sysfs/group.c:278 [inline]
WARNING: CPU: 1 PID: 2883 at fs/sysfs/group.c:278
sysfs_remove_group+0x155/0x1b0 fs/sysfs/group.c:269
Kernel panic - not syncing: panic_on_warn set ...
CPU: 1 PID: 2883 Comm: v4l_id Not tainted 5.3.0-rc7+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0xca/0x13e lib/dump_stack.c:113
panic+0x2a3/0x6da kernel/panic.c:219
__warn.cold+0x20/0x4a kernel/panic.c:576
report_bug+0x262/0x2a0 lib/bug.c:186
fixup_bug arch/x86/kernel/traps.c:179 [inline]
fixup_bug arch/x86/kernel/traps.c:174 [inline]
do_error_trap+0x12b/0x1e0 arch/x86/kernel/traps.c:272
do_invalid_op+0x32/0x40 arch/x86/kernel/traps.c:291
invalid_op+0x23/0x30 arch/x86/entry/entry_64.S:1028
RIP: 0010:sysfs_remove_group fs/sysfs/group.c:278 [inline]
RIP: 0010:sysfs_remove_group+0x155/0x1b0 fs/sysfs/group.c:269
Code: 48 89 d9 49 8b 14 24 48 b8 00 00 00 00 00 fc ff df 48 c1 e9 03 80 3c
01 00 75 41 48 8b 33 48 c7 c7 e0 c8 d0 85 e8 a0 0e 8b ff <0f> 0b eb 95 e8
e2 d1 db ff e9 d2 fe ff ff 48 89 df e8 d5 d1 db ff
RSP: 0018:ffff8881c6d17c50 EFLAGS: 00010286
RAX: 0000000000000000 RBX: ffffffff85f2d700 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff81288ddd RDI: ffffed1038da2f7c
RBP: 0000000000000000 R08: ffff8881d6243000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff8881cf014cd8
R13: ffffffff85f2dca0 R14: 0000000000000000 R15: ffff8881cf015178
dpm_sysfs_remove+0x97/0xb0 drivers/base/power/sysfs.c:735
device_del+0x12a/0xb10 drivers/base/core.c:2316
device_unregister+0x11/0x30 drivers/base/core.c:2371
video_unregister_device+0xa2/0xc0 drivers/media/v4l2-core/v4l2-dev.c:1051
usbvision_unregister_video+0x83/0x120
drivers/media/usb/usbvision/usbvision-video.c:1243
usbvision_release+0x10d/0x1c0
drivers/media/usb/usbvision/usbvision-video.c:1356
usbvision_radio_close.cold+0x2b/0x74
drivers/media/usb/usbvision/usbvision-video.c:1129
v4l2_release+0x2e7/0x390 drivers/media/v4l2-core/v4l2-dev.c:455
__fput+0x2d7/0x840 fs/file_table.c:280
task_work_run+0x13f/0x1c0 kernel/task_work.c:113
tracehook_notify_resume include/linux/tracehook.h:188 [inline]
exit_to_usermode_loop+0x1d2/0x200 arch/x86/entry/common.c:163
prepare_exit_to_usermode arch/x86/entry/common.c:194 [inline]
syscall_return_slowpath arch/x86/entry/common.c:274 [inline]
do_syscall_64+0x45f/0x580 arch/x86/entry/common.c:299
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7f4fde8992b0
Code: 40 75 0b 31 c0 48 83 c4 08 e9 0c ff ff ff 48 8d 3d c5 32 08 00 e8 c0
07 02 00 83 3d 45 a3 2b 00 00 75 10 b8 03 00 00 00 0f 05 <48> 3d 01 f0 ff
ff 73 31 c3 48 83 ec 08 e8 ce 8a 01 00 48 89 04 24
RSP: 002b:00007ffcce3d65f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000003 RCX: 00007f4fde8992b0
RDX: 0000000000000013 RSI: 0000000080685600 RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000400884
R13: 00007ffcce3d6750 R14: 0000000000000000 R15: 0000000000000000
Kernel Offset: disabled
Rebooting in 86400 seconds..


Tested on:

commit: f0df5c1b usb-fuzzer: main usb gadget fuzzer driver
git tree: https://github.com/google/kasan.git
console output: https://syzkaller.appspot.com/x/log.txt?x=178ba88d600000
kernel config: https://syzkaller.appspot.com/x/.config?x=5c6633fa4ed00be5
dashboard link: https://syzkaller.appspot.com/bug?extid=7fa38a608b1075dfd634
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
patch: https://syzkaller.appspot.com/x/patch.diff?x=14ce1b59600000

Alan Stern

unread,
Sep 17, 2019, 1:36:02 PM9/17/19
to syzbot, andre...@google.com, gre...@linuxfoundation.org, kai.he...@canonical.com, linux-...@vger.kernel.org, linu...@vger.kernel.org, ma...@mansr.com, one...@suse.com, syzkall...@googlegroups.com
On Tue, 17 Sep 2019, syzbot wrote:

This is more than I can fix. The whole way the v4l2 layer handles
reference counting seems suspicious and I don't understand it. (Does
the code assume that the only reference holders are initial
registration and open files?)

In this case it looks like the device may be unregistered twice. It's
hard to tell exactly what's going wrong without knowing more about how
this is supposed to work. It wouldn't hurt, for example, to use
dev_info() instead of printk(KERN_INFO) in places like
usbvision_disconnect().

I'm going to step back and let the maintainers deal with the rest of
this.

Alan Stern

Alan Stern

unread,
Sep 17, 2019, 2:08:10 PM9/17/19
to syzbot, andre...@google.com, gre...@linuxfoundation.org, kai.he...@canonical.com, linux-...@vger.kernel.org, linu...@vger.kernel.org, ma...@mansr.com, one...@suse.com, syzkall...@googlegroups.com
Changed my mind. There are some obvious races between the open, close,
and disconnect routines. Maybe fixing them will help.

Alan Stern

#syz test: https://github.com/google/kasan.git f0df5c1b

drivers/media/usb/usbvision/usbvision-video.c | 27 ++++++++++++++++++++++----
1 file changed, 23 insertions(+), 4 deletions(-)

Index: usb-devel/drivers/media/usb/usbvision/usbvision-video.c
===================================================================
--- usb-devel.orig/drivers/media/usb/usbvision/usbvision-video.c
+++ usb-devel/drivers/media/usb/usbvision/usbvision-video.c
@@ -314,6 +314,10 @@ static int usbvision_v4l2_open(struct fi
if (mutex_lock_interruptible(&usbvision->v4l2_lock))
return -ERESTARTSYS;

+ if (usbvision->remove_pending) {
+ err_code = -ENODEV;
+ goto unlock;
+ }
if (usbvision->user) {
err_code = -EBUSY;
} else {
@@ -377,6 +381,7 @@ unlock:
static int usbvision_v4l2_close(struct file *file)
{
struct usb_usbvision *usbvision = video_drvdata(file);
+ int r;

PDEBUG(DBG_IO, "close");

@@ -391,9 +396,10 @@ static int usbvision_v4l2_close(struct f
usbvision_scratch_free(usbvision);

usbvision->user--;
+ r = usbvision->remove_pending;
mutex_unlock(&usbvision->v4l2_lock);

- if (usbvision->remove_pending) {
+ if (r) {
printk(KERN_INFO "%s: Final disconnect\n", __func__);
usbvision_release(usbvision);
return 0;
@@ -453,6 +459,9 @@ static int vidioc_querycap(struct file *
{
struct usb_usbvision *usbvision = video_drvdata(file);

+ if (!usbvision->dev)
+ return -ENODEV;
+
strscpy(vc->driver, "USBVision", sizeof(vc->driver));
strscpy(vc->card,
usbvision_device_data[usbvision->dev_model].model_string,
@@ -1073,6 +1082,11 @@ static int usbvision_radio_open(struct f

if (mutex_lock_interruptible(&usbvision->v4l2_lock))
return -ERESTARTSYS;
+
+ if (usbvision->remove_pending) {
+ err_code = -ENODEV;
+ goto out;
+ }
err_code = v4l2_fh_open(file);
if (err_code)
goto out;
@@ -1105,21 +1119,24 @@ out:
static int usbvision_radio_close(struct file *file)
{
struct usb_usbvision *usbvision = video_drvdata(file);
+ int r;

PDEBUG(DBG_IO, "");

mutex_lock(&usbvision->v4l2_lock);
/* Set packet size to 0 */
usbvision->iface_alt = 0;
- usb_set_interface(usbvision->dev, usbvision->iface,
+ if (usbvision->dev)
+ usb_set_interface(usbvision->dev, usbvision->iface,
usbvision->iface_alt);

usbvision_audio_off(usbvision);
usbvision->radio = 0;
usbvision->user--;
+ r = usbvision->remove_pending;
mutex_unlock(&usbvision->v4l2_lock);

- if (usbvision->remove_pending) {
+ if (r) {
printk(KERN_INFO "%s: Final disconnect\n", __func__);
v4l2_fh_release(file);
usbvision_release(usbvision);
@@ -1551,6 +1568,7 @@ err_usb:
static void usbvision_disconnect(struct usb_interface *intf)
{
struct usb_usbvision *usbvision = to_usbvision(usb_get_intfdata(intf));
+ int u;

PDEBUG(DBG_PROBE, "");

@@ -1567,13 +1585,14 @@ static void usbvision_disconnect(struct
v4l2_device_disconnect(&usbvision->v4l2_dev);
usbvision_i2c_unregister(usbvision);
usbvision->remove_pending = 1; /* Now all ISO data will be ignored */
+ u = usbvision_user;

usb_put_dev(usbvision->dev);
usbvision->dev = NULL; /* USB device is no more */

mutex_unlock(&usbvision->v4l2_lock);

- if (usbvision->user) {
+ if (u) {
printk(KERN_INFO "%s: In use, disconnect pending\n",
__func__);
wake_up_interruptible(&usbvision->wait_frame);

syzbot

unread,
Sep 17, 2019, 2:15:01 PM9/17/19
to andre...@google.com, gre...@linuxfoundation.org, kai.he...@canonical.com, linux-...@vger.kernel.org, linu...@vger.kernel.org, ma...@mansr.com, one...@suse.com, st...@rowland.harvard.edu, syzkall...@googlegroups.com
Hello,

syzbot tried to test the proposed patch but build/boot failed:

drivers/usb/typec/altmodes/built-in.a
CC drivers/usb/misc/legousbtower.o
AR drivers/usb/musb/built-in.a
CC drivers/usb/host/sl811-hcd.o
CC drivers/usb/usbip/vhci_sysfs.o
AR drivers/usb/typec/mux/built-in.a
CC drivers/usb/serial/generic.o
CC drivers/usb/serial/bus.o
CC drivers/usb/usbip/vhci_tx.o
CC drivers/usb/serial/aircable.o
CC drivers/usb/typec/tcpm/tcpm.o
CC drivers/staging/rtl8712/usb_halinit.o
CC drivers/net/wireless/realtek/rtlwifi/rtl8192ee/dm.o
AR drivers/media/usb/zr364xx/built-in.a
CC drivers/staging/uwb/driver.o
CC drivers/staging/rtl8712/usb_ops.o
CC drivers/staging/rtl8712/usb_ops_linux.o
CC drivers/staging/rtl8712/rtl871x_io.o
CC drivers/staging/rtl8712/rtl8712_io.o
CC drivers/media/usb/uvc/uvc_debugfs.o
CC drivers/net/wireless/realtek/rtlwifi/rtl8192ce/rf.o
CC drivers/net/wireless/realtek/rtlwifi/rtl8192ee/fw.o
CC drivers/net/wireless/realtek/rtlwifi/rtl8192ce/phy.o
CC drivers/media/usb/uvc/uvc_metadata.o
CC drivers/usb/serial/ark3116.o
CC drivers/net/wireless/realtek/rtlwifi/rtl8192ce/sw.o
CC drivers/usb/serial/belkin_sa.o
CC drivers/media/usb/uvc/uvc_entity.o
CC drivers/net/wireless/realtek/rtlwifi/rtl8192ee/hw.o
CC drivers/gpu/drm/i915/i915_oa_sklgt4.o
CC drivers/gpu/drm/i915/i915_oa_bxt.o
CC drivers/usb/misc/rio500.o
CC drivers/usb/misc/usbtest.o
CC drivers/staging/wlan-ng/prism2usb.o
CC drivers/usb/misc/ehset.o
CC drivers/usb/serial/ch341.o
CC drivers/usb/storage/protocol.o
CC drivers/usb/typec/ucsi/trace.o
AR drivers/net/wireless/realtek/rtlwifi/rtl8192cu/built-in.a
CC drivers/usb/usbip/vhci_rx.o
CC drivers/usb/usbip/vhci_hcd.o
CC drivers/usb/misc/trancevibrator.o
CC drivers/usb/typec/ucsi/ucsi.o
CC drivers/net/wireless/realtek/rtlwifi/rtl8192de/fw.o
CC drivers/staging/uwb/drp.o
CC drivers/usb/host/sl811_cs.o
CC drivers/staging/uwb/drp-avail.o
CC drivers/usb/host/u132-hcd.o
CC drivers/staging/rtl8712/rtl871x_ioctl_linux.o
CC drivers/net/wireless/realtek/rtlwifi/rtl8192ce/table.o
AR drivers/media/usb/uvc/built-in.a
scripts/Makefile.build:497: recipe for target 'drivers/media/usb' failed
make[2]: *** [drivers/media/usb] Error 2
scripts/Makefile.build:497: recipe for target 'drivers/media' failed
make[1]: *** [drivers/media] Error 2
make[1]: *** Waiting for unfinished jobs....
CC drivers/usb/misc/uss720.o
CC drivers/usb/storage/transport.o
CC drivers/usb/misc/usbsevseg.o
CC drivers/usb/usbip/stub_dev.o
CC drivers/usb/misc/usb251xb.o
CC drivers/staging/uwb/drp-ie.o
CC drivers/usb/serial/cp210x.o
CC drivers/usb/serial/cyberjack.o
CC drivers/usb/serial/cypress_m8.o
CC drivers/gpu/drm/i915/i915_oa_kblgt2.o
CC drivers/usb/host/bcma-hcd.o
CC drivers/usb/host/r8a66597-hcd.o
CC drivers/usb/misc/yurex.o
CC drivers/usb/misc/usb3503.o
CC drivers/net/wireless/realtek/rtlwifi/rtl8192ee/led.o
CC drivers/staging/wlan-ng/p80211conv.o
CC drivers/usb/host/ssb-hcd.o
CC drivers/net/wireless/realtek/rtlwifi/rtl8192ee/phy.o
CC drivers/net/wireless/realtek/rtlwifi/rtl8192ce/trx.o
CC drivers/staging/uwb/est.o
CC drivers/usb/misc/usb4604.o
CC drivers/usb/misc/chaoskey.o
CC drivers/net/wireless/realtek/rtlwifi/rtl8192se/dm.o
CC drivers/net/wireless/realtek/rtlwifi/rtl8192se/fw.o
CC drivers/staging/rtl8712/rtl871x_ioctl_rtl.o
CC drivers/usb/usbip/stub_main.o
CC drivers/usb/misc/lvstest.o
CC drivers/usb/storage/usb.o
CC drivers/usb/storage/initializers.o
CC drivers/usb/storage/sierra_ms.o
CC drivers/gpu/drm/drm_vblank.o
CC drivers/gpu/drm/drm_syncobj.o
CC drivers/usb/typec/ucsi/ucsi_acpi.o
CC drivers/net/wireless/realtek/rtlwifi/rtl8192de/hw.o
CC drivers/usb/host/fotg210-hcd.o
CC drivers/staging/uwb/ie.o
CC drivers/gpu/drm/i915/i915_oa_kblgt3.o
CC drivers/staging/wlan-ng/p80211req.o
CC drivers/net/wireless/realtek/rtlwifi/rtl8192ee/pwrseq.o
CC drivers/staging/wlan-ng/p80211wep.o
CC drivers/staging/wlan-ng/p80211netdev.o
CC drivers/usb/serial/usb_debug.o
CC drivers/staging/rtl8712/rtl871x_ioctl_set.o
CC drivers/net/wireless/realtek/rtlwifi/rtl8192de/led.o
CC drivers/net/wireless/realtek/rtlwifi/rtl8192se/hw.o
CC drivers/usb/usbip/stub_rx.o
CC drivers/net/wireless/realtek/rtlwifi/rtl8192se/led.o
CC drivers/usb/usbip/stub_tx.o
CC drivers/staging/uwb/ie-rcv.o
CC drivers/usb/typec/class.o
CC drivers/usb/serial/digi_acceleport.o
AR drivers/usb/typec/ucsi/built-in.a
AR drivers/usb/misc/built-in.a
CC drivers/gpu/drm/i915/i915_oa_glk.o
CC drivers/staging/uwb/lc-dev.o
CC drivers/net/wireless/realtek/rtlwifi/rtl8192se/phy.o
CC drivers/net/wireless/realtek/rtlwifi/rtl8192se/rf.o
CC drivers/usb/usbip/vudc_dev.o
AR drivers/net/wireless/realtek/rtlwifi/rtl8192ce/built-in.a
CC drivers/usb/typec/tcpm/fusb302.o
CC drivers/usb/storage/option_ms.o
CC drivers/usb/storage/usual-tables.o
CC drivers/net/wireless/realtek/rtlwifi/rtl8192de/phy.o
CC drivers/staging/rtl8712/rtl8712_led.o
CC drivers/usb/typec/mux.o
CC drivers/usb/typec/bus.o
CC drivers/usb/typec/tcpm/tcpci.o
CC drivers/gpu/drm/i915/i915_oa_cflgt2.o
CC drivers/gpu/drm/i915/i915_oa_cflgt3.o
CC drivers/net/wireless/realtek/rtlwifi/rtl8192ee/rf.o
CC drivers/staging/uwb/lc-rc.o
CC drivers/net/wireless/realtek/rtlwifi/rtl8192de/rf.o
CC drivers/usb/host/max3421-hcd.o
CC drivers/usb/usbip/vudc_sysfs.o
CC drivers/usb/serial/io_edgeport.o
CC drivers/usb/serial/io_ti.o
CC drivers/net/wireless/realtek/rtlwifi/rtl8192de/sw.o
CC drivers/usb/typec/tps6598x.o
CC drivers/usb/storage/alauda.o
CC drivers/usb/storage/cypress_atacb.o
CC drivers/usb/storage/datafab.o
CC drivers/gpu/drm/i915/i915_oa_cnl.o
CC drivers/usb/usbip/vudc_tx.o
CC drivers/net/wireless/realtek/rtlwifi/rtl8192ee/sw.o
CC drivers/staging/rtl8712/rtl871x_mlme.o
CC drivers/staging/rtl8712/ieee80211.o
CC drivers/staging/uwb/neh.o
CC drivers/usb/usbip/vudc_rx.o
CC drivers/net/wireless/realtek/rtlwifi/rtl8192ee/table.o
CC drivers/net/wireless/realtek/rtlwifi/rtl8192se/sw.o
AR drivers/usb/typec/tcpm/built-in.a
CC drivers/gpu/drm/drm_lease.o
CC drivers/net/wireless/realtek/rtlwifi/rtl8192de/table.o
CC drivers/net/wireless/realtek/rtlwifi/rtl8192ee/trx.o
AR drivers/usb/typec/built-in.a
CC drivers/staging/uwb/pal.o
CC drivers/staging/uwb/radio.o
CC drivers/net/wireless/realtek/rtlwifi/rtl8192de/trx.o
CC drivers/staging/uwb/reset.o
CC drivers/usb/usbip/vudc_transfer.o
CC drivers/gpu/drm/drm_writeback.o
CC drivers/usb/usbip/vudc_main.o
AR drivers/staging/wlan-ng/built-in.a
CC drivers/gpu/drm/drm_client.o
CC drivers/usb/storage/ene_ub6250.o
CC drivers/staging/uwb/rsv.o
CC drivers/usb/serial/empeg.o
CC drivers/net/wireless/realtek/rtlwifi/rtl8723ae/dm.o
CC drivers/net/wireless/realtek/rtlwifi/rtl8723ae/fw.o
CC drivers/net/wireless/realtek/rtlwifi/rtl8192se/table.o
CC drivers/usb/serial/f81232.o
CC drivers/net/wireless/realtek/rtlwifi/rtl8723be/dm.o
CC drivers/net/wireless/realtek/rtlwifi/rtl8723be/fw.o
CC drivers/staging/uwb/scan.o
CC drivers/net/wireless/realtek/rtlwifi/rtl8192se/trx.o
CC drivers/staging/rtl8712/rtl871x_mp_ioctl.o
CC drivers/staging/uwb/uwb-debug.o
CC drivers/usb/storage/freecom.o
CC drivers/gpu/drm/i915/i915_oa_icl.o
CC drivers/usb/serial/f81534.o
CC drivers/net/wireless/realtek/rtlwifi/rtl8723be/hw.o
CC drivers/net/wireless/realtek/rtlwifi/base.o
CC drivers/net/wireless/realtek/rtlwifi/cam.o
CC drivers/gpu/drm/drm_client_modeset.o
CC drivers/gpu/drm/drm_hdcp.o
AR drivers/net/wireless/realtek/rtlwifi/rtl8192ee/built-in.a
CC drivers/gpu/drm/drm_ioc32.o
CC drivers/net/wireless/realtek/rtlwifi/rtl8821ae/dm.o
AR drivers/usb/usbip/built-in.a
CC drivers/net/wireless/realtek/rtlwifi/rtl8821ae/fw.o
CC drivers/net/wireless/realtek/rtlwifi/rtl8821ae/hw.o
CC drivers/net/wireless/realtek/rtlwifi/rtl8723com/main.o
CC drivers/net/wireless/realtek/rtlwifi/rtl8821ae/led.o
CC drivers/gpu/drm/drm_atomic_uapi.o
CC drivers/usb/serial/ftdi_sio.o
CC drivers/staging/rtl8712/rtl871x_mp.o
CC drivers/staging/wusbcore/host/whci/asl.o
CC drivers/gpu/drm/drm_panel.o
CC drivers/gpu/drm/drm_of.o
AR drivers/usb/host/built-in.a
CC drivers/net/wireless/realtek/rtlwifi/rtl8723com/dm_common.o
CC drivers/usb/serial/garmin_gps.o
CC drivers/net/wireless/realtek/rtlwifi/rtl8723com/fw_common.o
CC drivers/staging/uwb/uwbd.o
CC drivers/net/wireless/realtek/rtlwifi/rtl8723com/phy_common.o
CC drivers/usb/storage/isd200.o
CC drivers/net/wireless/realtek/rtlwifi/core.o
AR drivers/gpu/drm/i915/built-in.a
CC drivers/usb/serial/ipaq.o
CC drivers/staging/rtl8712/mlme_linux.o
CC drivers/net/wireless/realtek/rtlwifi/debug.o
CC drivers/net/wireless/realtek/rtlwifi/efuse.o
CC drivers/staging/uwb/umc-bus.o
CC drivers/staging/uwb/umc-dev.o
CC drivers/staging/uwb/umc-drv.o
CC drivers/staging/wusbcore/host/whci/debug.o
CC drivers/staging/wusbcore/crypto.o
CC drivers/gpu/drm/drm_agpsupport.o
AR drivers/net/wireless/realtek/rtlwifi/rtl8192se/built-in.a
CC drivers/net/wireless/realtek/rtlwifi/rtl8723ae/hal_btc.o
CC drivers/net/wireless/realtek/rtlwifi/rtl8723ae/hal_bt_coexist.o
CC drivers/net/wireless/realtek/rtlwifi/rtl8723ae/hw.o
CC drivers/staging/rtl8712/recv_linux.o
CC drivers/staging/wusbcore/devconnect.o
CC drivers/staging/wusbcore/dev-sysfs.o
CC drivers/staging/uwb/whci.o
CC drivers/staging/wusbcore/mmc.o
CC drivers/staging/wusbcore/pal.o
CC drivers/staging/wusbcore/host/whci/hcd.o
CC drivers/net/wireless/realtek/rtlwifi/rtl8723be/led.o
CC drivers/net/wireless/realtek/rtlwifi/rtl8723be/phy.o
CC drivers/net/wireless/realtek/rtlwifi/rtl8723be/pwrseq.o
CC drivers/staging/rtl8712/xmit_linux.o
CC drivers/staging/rtl8712/usb_intf.o
CC drivers/gpu/drm/drm_debugfs.o
CC drivers/usb/storage/jumpshot.o
CC drivers/staging/uwb/whc-rc.o
CC drivers/gpu/drm/drm_debugfs_crc.o
CC drivers/usb/storage/karma.o
CC drivers/usb/serial/ipw.o
CC drivers/usb/storage/onetouch.o
CC drivers/usb/serial/ir-usb.o
CC drivers/gpu/drm/drm_mipi_dsi.o
CC drivers/net/wireless/realtek/rtlwifi/ps.o
AR drivers/net/wireless/realtek/rtlwifi/rtl8192de/built-in.a
CC drivers/staging/wusbcore/host/hwa-hc.o
CC drivers/staging/uwb/hwa-rc.o
CC drivers/staging/wusbcore/rh.o
AR drivers/net/wireless/realtek/rtlwifi/rtl8723com/built-in.a
CC drivers/staging/wusbcore/reservation.o
CC drivers/staging/rtl8712/os_intfs.o
CC drivers/net/wireless/realtek/rtlwifi/rtl8723ae/led.o
CC drivers/staging/wusbcore/host/whci/hw.o
CC drivers/usb/storage/realtek_cr.o
CC drivers/staging/wusbcore/host/whci/init.o
CC drivers/staging/wusbcore/host/whci/int.o
CC drivers/staging/rtl8712/rtl871x_pwrctrl.o
CC drivers/usb/storage/sddr09.o
CC drivers/usb/serial/iuu_phoenix.o
CC drivers/net/wireless/realtek/rtlwifi/rtl8723be/sw.o
CC drivers/staging/rtl8712/rtl8712_recv.o
CC drivers/usb/storage/sddr55.o
CC drivers/net/wireless/realtek/rtlwifi/rtl8723be/rf.o
CC drivers/gpu/drm/drm_panel_orientation_quirks.o
CC drivers/usb/storage/shuttle_usbat.o
CC drivers/staging/wusbcore/security.o
CC drivers/net/wireless/realtek/rtlwifi/rtl8723ae/phy.o
CC drivers/net/wireless/realtek/rtlwifi/rtl8723ae/pwrseq.o
CC drivers/net/wireless/realtek/rtlwifi/rtl8723ae/rf.o
CC drivers/net/wireless/realtek/rtlwifi/rtl8723ae/sw.o
CC drivers/staging/wusbcore/wusbhc.o
CC drivers/staging/rtl8712/rtl871x_recv.o
CC drivers/staging/rtl8712/rtl871x_sta_mgt.o
CC drivers/staging/rtl8712/rtl871x_xmit.o
CC drivers/staging/rtl8712/rtl8712_xmit.o
CC drivers/net/wireless/realtek/rtlwifi/rtl8723be/table.o
CC drivers/net/wireless/realtek/rtlwifi/rtl8723be/trx.o
CC drivers/usb/serial/keyspan.o
CC drivers/usb/serial/keyspan_pda.o
AR drivers/staging/uwb/built-in.a
AR drivers/gpu/drm/built-in.a
CC drivers/staging/wusbcore/wa-hc.o
CC drivers/net/wireless/realtek/rtlwifi/rtl8821ae/phy.o
CC drivers/net/wireless/realtek/rtlwifi/rtl8821ae/pwrseq.o
CC drivers/net/wireless/realtek/rtlwifi/rtl8821ae/rf.o
CC drivers/staging/wusbcore/host/whci/qset.o
CC drivers/staging/wusbcore/host/whci/pzl.o
AR drivers/gpu/built-in.a
CC drivers/staging/wusbcore/host/whci/wusb.o
CC drivers/net/wireless/realtek/rtlwifi/rtl8723ae/trx.o
CC drivers/net/wireless/realtek/rtlwifi/rc.o
CC drivers/net/wireless/realtek/rtlwifi/regd.o
CC drivers/net/wireless/realtek/rtlwifi/rtl8821ae/sw.o
CC drivers/net/wireless/realtek/rtlwifi/rtl8723ae/table.o
CC drivers/net/wireless/realtek/rtlwifi/stats.o
CC drivers/net/wireless/realtek/rtlwifi/pci.o
CC drivers/staging/wusbcore/wa-rpipe.o
CC drivers/staging/wusbcore/wa-nep.o
AR drivers/usb/storage/built-in.a
CC drivers/net/wireless/realtek/rtlwifi/usb.o
CC drivers/net/wireless/realtek/rtlwifi/rtl8821ae/table.o
CC drivers/net/wireless/realtek/rtlwifi/rtl8821ae/trx.o
CC drivers/staging/wusbcore/wa-xfer.o
CC drivers/staging/wusbcore/cbaf.o
CC drivers/usb/serial/kobil_sct.o
CC drivers/usb/serial/kl5kusb105.o
CC drivers/usb/serial/metro-usb.o
CC drivers/usb/serial/mct_u232.o
CC drivers/usb/serial/mos7720.o
CC drivers/usb/serial/mos7840.o
CC drivers/usb/serial/mxuport.o
CC drivers/usb/serial/navman.o
CC drivers/usb/serial/omninet.o
CC drivers/usb/serial/opticon.o
CC drivers/usb/serial/option.o
CC drivers/usb/serial/oti6858.o
CC drivers/usb/serial/pl2303.o
CC drivers/usb/serial/qcaux.o
CC drivers/usb/serial/qcserial.o
CC drivers/usb/serial/quatech2.o
CC drivers/usb/serial/safe_serial.o
AR drivers/staging/rtl8712/built-in.a
CC drivers/usb/serial/sierra.o
AR drivers/net/wireless/realtek/rtlwifi/rtl8723be/built-in.a
CC drivers/usb/serial/usb-serial-simple.o
CC drivers/usb/serial/spcp8x5.o
AR drivers/staging/wusbcore/host/whci/built-in.a
AR drivers/staging/wusbcore/host/built-in.a
CC drivers/usb/serial/ssu100.o
CC drivers/usb/serial/symbolserial.o
CC drivers/usb/serial/usb_wwan.o
CC drivers/usb/serial/ti_usb_3410_5052.o
CC drivers/usb/serial/upd78f0730.o
CC drivers/usb/serial/visor.o
AR drivers/net/wireless/realtek/rtlwifi/rtl8723ae/built-in.a
CC drivers/usb/serial/wishbone-serial.o
CC drivers/usb/serial/xsens_mt.o
CC drivers/usb/serial/whiteheat.o
AR drivers/staging/wusbcore/built-in.a
AR drivers/staging/built-in.a
AR drivers/usb/serial/built-in.a
AR drivers/usb/built-in.a
AR drivers/net/wireless/realtek/rtlwifi/rtl8821ae/built-in.a
AR drivers/net/wireless/realtek/rtlwifi/built-in.a
AR drivers/net/wireless/realtek/built-in.a
AR drivers/net/wireless/built-in.a
AR drivers/net/built-in.a
Makefile:1083: recipe for target 'drivers' failed
make: *** [drivers] Error 2


Error text is too large and was truncated, full error text is at:
https://syzkaller.appspot.com/x/error.txt?x=176045b5600000


Tested on:

commit: f0df5c1b usb-fuzzer: main usb gadget fuzzer driver
git tree: https://github.com/google/kasan.git
dashboard link: https://syzkaller.appspot.com/bug?extid=7fa38a608b1075dfd634
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
patch: https://syzkaller.appspot.com/x/patch.diff?x=12f8611d600000

Alan Stern

unread,
Sep 17, 2019, 2:31:31 PM9/17/19
to syzbot, andre...@google.com, gre...@linuxfoundation.org, kai.he...@canonical.com, linux-...@vger.kernel.org, linu...@vger.kernel.org, ma...@mansr.com, one...@suse.com, syzkall...@googlegroups.com
On Tue, 17 Sep 2019, syzbot wrote:

> Hello,
>
> syzbot tried to test the proposed patch but build/boot failed:

Oops. Typo.
+ u = usbvision->user;

syzbot

unread,
Sep 17, 2019, 2:43:01 PM9/17/19
to andre...@google.com, gre...@linuxfoundation.org, kai.he...@canonical.com, linux-...@vger.kernel.org, linu...@vger.kernel.org, ma...@mansr.com, one...@suse.com, st...@rowland.harvard.edu, syzkall...@googlegroups.com
Hello,

syzbot has tested the proposed patch but the reproducer still triggered
crash:
WARNING in sysfs_remove_group

------------[ cut here ]------------
sysfs group 'power' not found for kobject 'radio0'
WARNING: CPU: 0 PID: 2871 at fs/sysfs/group.c:278 sysfs_remove_group
fs/sysfs/group.c:278 [inline]
WARNING: CPU: 0 PID: 2871 at fs/sysfs/group.c:278
sysfs_remove_group+0x155/0x1b0 fs/sysfs/group.c:269
Kernel panic - not syncing: panic_on_warn set ...
CPU: 0 PID: 2871 Comm: v4l_id Not tainted 5.3.0-rc7+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0xca/0x13e lib/dump_stack.c:113
panic+0x2a3/0x6da kernel/panic.c:219
__warn.cold+0x20/0x4a kernel/panic.c:576
report_bug+0x262/0x2a0 lib/bug.c:186
fixup_bug arch/x86/kernel/traps.c:179 [inline]
fixup_bug arch/x86/kernel/traps.c:174 [inline]
do_error_trap+0x12b/0x1e0 arch/x86/kernel/traps.c:272
do_invalid_op+0x32/0x40 arch/x86/kernel/traps.c:291
invalid_op+0x23/0x30 arch/x86/entry/entry_64.S:1028
RIP: 0010:sysfs_remove_group fs/sysfs/group.c:278 [inline]
RIP: 0010:sysfs_remove_group+0x155/0x1b0 fs/sysfs/group.c:269
Code: 48 89 d9 49 8b 14 24 48 b8 00 00 00 00 00 fc ff df 48 c1 e9 03 80 3c
01 00 75 41 48 8b 33 48 c7 c7 e0 c8 d0 85 e8 a0 0e 8b ff <0f> 0b eb 95 e8
e2 d1 db ff e9 d2 fe ff ff 48 89 df e8 d5 d1 db ff
RSP: 0018:ffff8881c6c37c50 EFLAGS: 00010286
RAX: 0000000000000000 RBX: ffffffff85f2d700 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff81288ddd RDI: ffffed1038d86f7c
RBP: 0000000000000000 R08: ffff8881d5dab000 R09: ffffed103b643ee7
R10: ffffed103b643ee6 R11: ffff8881db21f737 R12: ffff8881cf7e2bd8
R13: ffffffff85f2dca0 R14: 0000000000000000 R15: ffff8881cf7e3078
dpm_sysfs_remove+0x97/0xb0 drivers/base/power/sysfs.c:735
device_del+0x12a/0xb10 drivers/base/core.c:2316
device_unregister+0x11/0x30 drivers/base/core.c:2371
video_unregister_device+0xa2/0xc0 drivers/media/v4l2-core/v4l2-dev.c:1051
usbvision_unregister_video+0x83/0x120
drivers/media/usb/usbvision/usbvision-video.c:1256
usbvision_release+0x10d/0x1c0
drivers/media/usb/usbvision/usbvision-video.c:1369
usbvision_radio_close.cold+0x2b/0x74
drivers/media/usb/usbvision/usbvision-video.c:1142
v4l2_release+0x2e7/0x390 drivers/media/v4l2-core/v4l2-dev.c:455
__fput+0x2d7/0x840 fs/file_table.c:280
task_work_run+0x13f/0x1c0 kernel/task_work.c:113
tracehook_notify_resume include/linux/tracehook.h:188 [inline]
exit_to_usermode_loop+0x1d2/0x200 arch/x86/entry/common.c:163
prepare_exit_to_usermode arch/x86/entry/common.c:194 [inline]
syscall_return_slowpath arch/x86/entry/common.c:274 [inline]
do_syscall_64+0x45f/0x580 arch/x86/entry/common.c:299
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7fa3a6eac2b0
Code: 40 75 0b 31 c0 48 83 c4 08 e9 0c ff ff ff 48 8d 3d c5 32 08 00 e8 c0
07 02 00 83 3d 45 a3 2b 00 00 75 10 b8 03 00 00 00 0f 05 <48> 3d 01 f0 ff
ff 73 31 c3 48 83 ec 08 e8 ce 8a 01 00 48 89 04 24
RSP: 002b:00007ffe36ff6c28 EFLAGS: 00000246 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000003 RCX: 00007fa3a6eac2b0
RDX: 0000000000000013 RSI: 0000000080685600 RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000400884
R13: 00007ffe36ff6d80 R14: 0000000000000000 R15: 0000000000000000
Kernel Offset: disabled
Rebooting in 86400 seconds..


Tested on:

commit: f0df5c1b usb-fuzzer: main usb gadget fuzzer driver
git tree: https://github.com/google/kasan.git
console output: https://syzkaller.appspot.com/x/log.txt?x=10621965600000
kernel config: https://syzkaller.appspot.com/x/.config?x=5c6633fa4ed00be5
dashboard link: https://syzkaller.appspot.com/bug?extid=7fa38a608b1075dfd634
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
patch: https://syzkaller.appspot.com/x/patch.diff?x=15fea979600000

syzbot

unread,
Sep 17, 2019, 4:30:02 PM9/17/19
to st...@rowland.harvard.edu, syzkall...@googlegroups.com
Hello,

syzbot has tested the proposed patch but the reproducer still triggered
crash:
general protection fault in usbvision_release

kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] SMP KASAN
CPU: 0 PID: 5 Comm: kworker/0:0 Not tainted 5.3.0-rc7+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Workqueue: usb_hub_wq hub_event
RIP: 0010:dev_name include/linux/device.h:1103 [inline]
RIP: 0010:__dev_printk+0x3a/0x203 drivers/base/core.c:3306
Code: 89 f5 53 e8 6f 79 d2 fe 48 85 ed 0f 84 bc 01 00 00 e8 61 79 d2 fe 48
8d 7d 50 b8 ff ff 37 00 48 89 fa 48 c1 e0 2a 48 c1 ea 03 <80> 3c 02 00 74
05 e8 d2 21 f9 fe 4c 8b 7d 50 4d 85 ff 75 27 e8 34
RSP: 0018:ffff8881da1c7750 EFLAGS: 00010206
RAX: dffffc0000000000 RBX: ffffed103b438ef1 RCX: ffffffff812497a2
RDX: 000000000000001e RSI: ffffffff826b613f RDI: 00000000000000f0
RBP: 00000000000000a0 R08: ffff8881da186000 R09: ffffed103ae8e017
R10: ffffed103ae8e016 R11: ffff8881d74700b7 R12: ffffffff85f279c0
R13: ffff8881da1c77a8 R14: ffff8881d74717f0 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff8881db200000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fff9654cee8 CR3: 00000001d1f2d000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
_dev_info+0xd7/0x109 drivers/base/core.c:3352
usbvision_release+0x1ad/0x210
drivers/media/usb/usbvision/usbvision-video.c:1379
usbvision_disconnect+0x171/0x1e0
drivers/media/usb/usbvision/usbvision-video.c:1606
usb_unbind_interface+0x1bd/0x8a0 drivers/usb/core/driver.c:423
__device_release_driver drivers/base/dd.c:1134 [inline]
device_release_driver_internal+0x42f/0x500 drivers/base/dd.c:1165
bus_remove_device+0x2dc/0x4a0 drivers/base/bus.c:556
device_del+0x420/0xb10 drivers/base/core.c:2339
usb_disable_device+0x211/0x690 drivers/usb/core/message.c:1237
usb_disconnect+0x284/0x8d0 drivers/usb/core/hub.c:2199
hub_port_connect drivers/usb/core/hub.c:4949 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5213 [inline]
port_event drivers/usb/core/hub.c:5359 [inline]
hub_event+0x1454/0x3640 drivers/usb/core/hub.c:5441
process_one_work+0x92b/0x1530 kernel/workqueue.c:2269
process_scheduled_works kernel/workqueue.c:2331 [inline]
worker_thread+0x7ab/0xe20 kernel/workqueue.c:2417
kthread+0x318/0x420 kernel/kthread.c:255
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352
Modules linked in:


Tested on:

commit: f0df5c1b usb-fuzzer: main usb gadget fuzzer driver
git tree: https://github.com/google/kasan.git
console output: https://syzkaller.appspot.com/x/log.txt?x=13279795600000
kernel config: https://syzkaller.appspot.com/x/.config?x=5c6633fa4ed00be5
dashboard link: https://syzkaller.appspot.com/bug?extid=7fa38a608b1075dfd634
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
patch: https://syzkaller.appspot.com/x/patch.diff?x=1328eb69600000

Alan Stern

unread,
Sep 18, 2019, 10:35:21 AM9/18/19
to syzbot, syzkall...@googlegroups.com
#syz test: https://github.com/google/kasan.git f0df5c1b

drivers/media/usb/usbvision/usbvision-video.c | 31 ++++++++++++++++++++++----
fs/sysfs/group.c | 8 ++++++
2 files changed, 35 insertions(+), 4 deletions(-)
@@ -1236,14 +1253,18 @@ static void usbvision_unregister_video(s
if (video_is_registered(&usbvision->rdev)) {
PDEBUG(DBG_PROBE, "unregister %s [v4l2]",
video_device_node_name(&usbvision->rdev));
+ dev_info(&usbvision->rdev.dev, "Unregister\n");
video_unregister_device(&usbvision->rdev);
+ printk(KERN_INFO "Unregister done\n");
}

/* Video Device: */
if (video_is_registered(&usbvision->vdev)) {
PDEBUG(DBG_PROBE, "unregister %s [v4l2]",
video_device_node_name(&usbvision->vdev));
+ dev_info(&usbvision->vdev.dev, "Unregister\n");
video_unregister_device(&usbvision->vdev);
+ printk(KERN_INFO "Unregister done\n");
}
}

@@ -1551,6 +1572,7 @@ err_usb:
static void usbvision_disconnect(struct usb_interface *intf)
{
struct usb_usbvision *usbvision = to_usbvision(usb_get_intfdata(intf));
+ int u;

PDEBUG(DBG_PROBE, "");

@@ -1567,13 +1589,14 @@ static void usbvision_disconnect(struct
v4l2_device_disconnect(&usbvision->v4l2_dev);
usbvision_i2c_unregister(usbvision);
usbvision->remove_pending = 1; /* Now all ISO data will be ignored */
+ u = usbvision->user;

usb_put_dev(usbvision->dev);
usbvision->dev = NULL; /* USB device is no more */

mutex_unlock(&usbvision->v4l2_lock);

- if (usbvision->user) {
+ if (u) {
printk(KERN_INFO "%s: In use, disconnect pending\n",
__func__);
wake_up_interruptible(&usbvision->wait_frame);
Index: usb-devel/fs/sysfs/group.c
===================================================================
--- usb-devel.orig/fs/sysfs/group.c
+++ usb-devel/fs/sysfs/group.c
@@ -273,6 +273,14 @@ void sysfs_remove_group(struct kobject *
struct kernfs_node *kn;

if (grp->name) {
+ const char *kname = kobject_name(kobj);
+
+ if (strcmp(grp->name, "power") == 0 &&
+ strncmp(kname, "radio", 5) == 0) {
+ pr_info("Removing '%s' from '%s'\n", grp->name, kname);
+ dump_stack();
+ }
+
kn = kernfs_find_and_get(parent, grp->name);
if (!kn) {
WARN(!kn, KERN_WARNING


syzbot

unread,
Sep 18, 2019, 11:01:03 AM9/18/19
to st...@rowland.harvard.edu, syzkall...@googlegroups.com
Hello,

syzbot has tested the proposed patch but the reproducer still triggered
crash:
WARNING in sysfs_remove_group

------------[ cut here ]------------
sysfs group 'power' not found for kobject 'radio0'
WARNING: CPU: 1 PID: 2868 at fs/sysfs/group.c:286
sysfs_remove_group+0x1d8/0x240 fs/sysfs/group.c:286
Kernel panic - not syncing: panic_on_warn set ...
CPU: 1 PID: 2868 Comm: v4l_id Not tainted 5.3.0-rc7+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0xca/0x13e lib/dump_stack.c:113
panic+0x2a3/0x6da kernel/panic.c:219
__warn.cold+0x20/0x4a kernel/panic.c:576
report_bug+0x262/0x2a0 lib/bug.c:186
fixup_bug arch/x86/kernel/traps.c:179 [inline]
fixup_bug arch/x86/kernel/traps.c:174 [inline]
do_error_trap+0x12b/0x1e0 arch/x86/kernel/traps.c:272
do_invalid_op+0x32/0x40 arch/x86/kernel/traps.c:291
invalid_op+0x23/0x30 arch/x86/entry/entry_64.S:1028
RIP: 0010:sysfs_remove_group+0x1d8/0x240 fs/sysfs/group.c:286
Code: 48 89 d9 49 8b 14 24 48 b8 00 00 00 00 00 fc ff df 48 c1 e9 03 80 3c
01 00 75 51 48 8b 33 48 c7 c7 a0 c9 d0 85 e8 1d 0e 8b ff <0f> 0b e9 3c ff
ff ff e8 5c d1 db ff e9 50 fe ff ff e8 52 d1 db ff
RSP: 0018:ffff8881c162fc40 EFLAGS: 00010282
RAX: 0000000000000000 RBX: ffffffff85f2d7c0 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff81288ddd RDI: ffffed10382c5f7a
RBP: 0000000000000000 R08: ffff8881d67d9800 R09: ffffed103b663ee7
R10: ffffed103b663ee6 R11: ffff8881db31f737 R12: ffff8881cf362bd8
R13: 0000000000000000 R14: ffffffff85f2dd60 R15: ffff8881d29114c8
dpm_sysfs_remove+0x97/0xb0 drivers/base/power/sysfs.c:735
device_del+0x12a/0xb10 drivers/base/core.c:2316
device_unregister+0x11/0x30 drivers/base/core.c:2371
video_unregister_device+0xa2/0xc0 drivers/media/v4l2-core/v4l2-dev.c:1051
usbvision_unregister_video.cold+0x1a5/0x1cb
drivers/media/usb/usbvision/usbvision-video.c:1257
usbvision_release+0x10d/0x1c0
drivers/media/usb/usbvision/usbvision-video.c:1373
usbvision_radio_close.cold+0x2b/0x74
drivers/media/usb/usbvision/usbvision-video.c:1142
v4l2_release+0x2e7/0x390 drivers/media/v4l2-core/v4l2-dev.c:455
__fput+0x2d7/0x840 fs/file_table.c:280
task_work_run+0x13f/0x1c0 kernel/task_work.c:113
tracehook_notify_resume include/linux/tracehook.h:188 [inline]
exit_to_usermode_loop+0x1d2/0x200 arch/x86/entry/common.c:163
prepare_exit_to_usermode arch/x86/entry/common.c:194 [inline]
syscall_return_slowpath arch/x86/entry/common.c:274 [inline]
do_syscall_64+0x45f/0x580 arch/x86/entry/common.c:299
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7f70fe5c32b0
Code: 40 75 0b 31 c0 48 83 c4 08 e9 0c ff ff ff 48 8d 3d c5 32 08 00 e8 c0
07 02 00 83 3d 45 a3 2b 00 00 75 10 b8 03 00 00 00 0f 05 <48> 3d 01 f0 ff
ff 73 31 c3 48 83 ec 08 e8 ce 8a 01 00 48 89 04 24
RSP: 002b:00007ffe90646f18 EFLAGS: 00000246 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000003 RCX: 00007f70fe5c32b0
RDX: 0000000000000013 RSI: 0000000080685600 RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000400884
R13: 00007ffe90647070 R14: 0000000000000000 R15: 0000000000000000
Kernel Offset: disabled
Rebooting in 86400 seconds..


Tested on:

commit: f0df5c1b usb-fuzzer: main usb gadget fuzzer driver
git tree: https://github.com/google/kasan.git
console output: https://syzkaller.appspot.com/x/log.txt?x=15a00d81600000
kernel config: https://syzkaller.appspot.com/x/.config?x=5c6633fa4ed00be5
dashboard link: https://syzkaller.appspot.com/bug?extid=7fa38a608b1075dfd634
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
patch: https://syzkaller.appspot.com/x/patch.diff?x=177e2cad600000

Alan Stern

unread,
Sep 18, 2019, 11:50:37 AM9/18/19
to syzbot, syzkall...@googlegroups.com
#syz test: https://github.com/google/kasan.git f0df5c1b

drivers/base/power/sysfs.c | 7 +++++-
drivers/media/usb/usbvision/usbvision-video.c | 29 ++++++++++++++++++++++----
fs/sysfs/group.c | 12 ++++++++++
3 files changed, 43 insertions(+), 5 deletions(-)
@@ -1236,7 +1253,9 @@ static void usbvision_unregister_video(s
if (video_is_registered(&usbvision->rdev)) {
PDEBUG(DBG_PROBE, "unregister %s [v4l2]",
video_device_node_name(&usbvision->rdev));
+ dev_info(&usbvision->rdev.dev, "Unregister\n");
video_unregister_device(&usbvision->rdev);
+ printk(KERN_INFO "Unregister done\n");
}

/* Video Device: */
@@ -1551,6 +1570,7 @@ err_usb:
static void usbvision_disconnect(struct usb_interface *intf)
{
struct usb_usbvision *usbvision = to_usbvision(usb_get_intfdata(intf));
+ int u;

PDEBUG(DBG_PROBE, "");

@@ -1567,13 +1587,14 @@ static void usbvision_disconnect(struct
v4l2_device_disconnect(&usbvision->v4l2_dev);
usbvision_i2c_unregister(usbvision);
usbvision->remove_pending = 1; /* Now all ISO data will be ignored */
+ u = usbvision->user;

usb_put_dev(usbvision->dev);
usbvision->dev = NULL; /* USB device is no more */

mutex_unlock(&usbvision->v4l2_lock);

- if (usbvision->user) {
+ if (u) {
printk(KERN_INFO "%s: In use, disconnect pending\n",
__func__);
wake_up_interruptible(&usbvision->wait_frame);
Index: usb-devel/fs/sysfs/group.c
===================================================================
--- usb-devel.orig/fs/sysfs/group.c
+++ usb-devel/fs/sysfs/group.c
@@ -125,6 +125,12 @@ static int internal_create_group(struct
}
kobject_get_ownership(kobj, &uid, &gid);
if (grp->name) {
+ const char *kname = kobject_name(kobj);
+
+ if (strcmp(grp->name, "power") == 0 &&
+ strncmp(kname, "radio", 5) == 0)
+ pr_info("Adding '%s' to '%s'\n", grp->name, kname);
+
if (update) {
kn = kernfs_find_and_get(kobj->sd, grp->name);
if (!kn) {
@@ -273,6 +279,12 @@ void sysfs_remove_group(struct kobject *
struct kernfs_node *kn;

if (grp->name) {
+ const char *kname = kobject_name(kobj);
+
+ if (strcmp(grp->name, "power") == 0 &&
+ strncmp(kname, "radio", 5) == 0)
+ pr_info("Removing '%s' from '%s'\n", grp->name, kname);
+
kn = kernfs_find_and_get(parent, grp->name);
if (!kn) {
WARN(!kn, KERN_WARNING
Index: usb-devel/drivers/base/power/sysfs.c
===================================================================
--- usb-devel.orig/drivers/base/power/sysfs.c
+++ usb-devel/drivers/base/power/sysfs.c
@@ -642,14 +642,18 @@ static const struct attribute_group pm_q
int dpm_sysfs_add(struct device *dev)
{
int rc;
+ int m = !strncmp(dev_name(dev), "radio", 5);

/* No need to create PM sysfs if explicitly disabled. */
if (device_pm_not_required(dev))
return 0;

+ if (m) dev_info(dev, "Registering 'power' group\n");
rc = sysfs_create_group(&dev->kobj, &pm_attr_group);
- if (rc)
+ if (rc) {
+ if (m) dev_info(dev, "Registration failed\n");
return rc;
+ }

if (pm_runtime_callbacks_present(dev)) {
rc = sysfs_merge_group(&dev->kobj, &pm_runtime_attr_group);
@@ -674,6 +678,7 @@ int dpm_sysfs_add(struct device *dev)
err_runtime:
sysfs_unmerge_group(&dev->kobj, &pm_runtime_attr_group);
err_out:
+ if (m) dev_info(dev, "Undo registration\n");
sysfs_remove_group(&dev->kobj, &pm_attr_group);
return rc;
}

syzbot

unread,
Sep 18, 2019, 12:32:01 PM9/18/19
to st...@rowland.harvard.edu, syzkall...@googlegroups.com
Hello,

syzbot has tested the proposed patch but the reproducer still triggered
crash:
WARNING in sysfs_remove_group

usbvision_radio_close: Final disconnect
video4linux radio6: Unregister
Removing 'power' from 'radio6'
------------[ cut here ]------------
sysfs group 'power' not found for kobject 'radio6'
WARNING: CPU: 1 PID: 2898 at fs/sysfs/group.c:290
sysfs_remove_group+0x1d8/0x240 fs/sysfs/group.c:290
Kernel panic - not syncing: panic_on_warn set ...
CPU: 1 PID: 2898 Comm: v4l_id Not tainted 5.3.0-rc7+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0xca/0x13e lib/dump_stack.c:113
panic+0x2a3/0x6da kernel/panic.c:219
__warn.cold+0x20/0x4a kernel/panic.c:576
report_bug+0x262/0x2a0 lib/bug.c:186
fixup_bug arch/x86/kernel/traps.c:179 [inline]
fixup_bug arch/x86/kernel/traps.c:174 [inline]
do_error_trap+0x12b/0x1e0 arch/x86/kernel/traps.c:272
do_invalid_op+0x32/0x40 arch/x86/kernel/traps.c:291
invalid_op+0x23/0x30 arch/x86/entry/entry_64.S:1028
RIP: 0010:sysfs_remove_group+0x1d8/0x240 fs/sysfs/group.c:290
Code: 48 89 d9 49 8b 14 24 48 b8 00 00 00 00 00 fc ff df 48 c1 e9 03 80 3c
01 00 75 51 48 8b 33 48 c7 c7 a0 c7 d0 85 e8 fd 19 8b ff <0f> 0b e9 3c ff
ff ff e8 3c dd db ff e9 50 fe ff ff e8 32 dd db ff
RSP: 0018:ffff8881c72afc40 EFLAGS: 00010282
RAX: 0000000000000000 RBX: ffffffff85f2d900 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff81288ddd RDI: ffffed1038e55f7a
RBP: 0000000000000000 R08: ffff8881d9251800 R09: ffffed103b663ee7
R10: ffffed103b663ee6 R11: ffff8881db31f737 R12: ffff8881d6b82bd8
R13: 0000000000000000 R14: ffffffff85f2dea0 R15: ffff8881d9ad6258
dpm_sysfs_remove+0x97/0xa5 drivers/base/power/sysfs.c:740
device_del+0x12a/0xb10 drivers/base/core.c:2316
device_unregister+0x11/0x30 drivers/base/core.c:2371
video_unregister_device+0xa2/0xc0 drivers/media/v4l2-core/v4l2-dev.c:1051
usbvision_unregister_video.cold+0x122/0x17c
drivers/media/usb/usbvision/usbvision-video.c:1257
usbvision_release+0x10d/0x1c0
drivers/media/usb/usbvision/usbvision-video.c:1371
usbvision_radio_close.cold+0x2b/0x74
drivers/media/usb/usbvision/usbvision-video.c:1142
v4l2_release+0x2e7/0x390 drivers/media/v4l2-core/v4l2-dev.c:455
__fput+0x2d7/0x840 fs/file_table.c:280
task_work_run+0x13f/0x1c0 kernel/task_work.c:113
tracehook_notify_resume include/linux/tracehook.h:188 [inline]
exit_to_usermode_loop+0x1d2/0x200 arch/x86/entry/common.c:163
prepare_exit_to_usermode arch/x86/entry/common.c:194 [inline]
syscall_return_slowpath arch/x86/entry/common.c:274 [inline]
do_syscall_64+0x45f/0x580 arch/x86/entry/common.c:299
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7f204f1de2b0
Code: 40 75 0b 31 c0 48 83 c4 08 e9 0c ff ff ff 48 8d 3d c5 32 08 00 e8 c0
07 02 00 83 3d 45 a3 2b 00 00 75 10 b8 03 00 00 00 0f 05 <48> 3d 01 f0 ff
ff 73 31 c3 48 83 ec 08 e8 ce 8a 01 00 48 89 04 24
RSP: 002b:00007ffe42a047c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000003 RCX: 00007f204f1de2b0
RDX: 0000000000000013 RSI: 0000000080685600 RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000400884
R13: 00007ffe42a04920 R14: 0000000000000000 R15: 0000000000000000
Kernel Offset: disabled
Rebooting in 86400 seconds..


Tested on:

commit: f0df5c1b usb-fuzzer: main usb gadget fuzzer driver
git tree: https://github.com/google/kasan.git
console output: https://syzkaller.appspot.com/x/log.txt?x=1469a31d600000
kernel config: https://syzkaller.appspot.com/x/.config?x=5c6633fa4ed00be5
dashboard link: https://syzkaller.appspot.com/bug?extid=7fa38a608b1075dfd634
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
patch: https://syzkaller.appspot.com/x/patch.diff?x=13cd5855600000

Alan Stern

unread,
Sep 18, 2019, 2:57:27 PM9/18/19
to syzbot, andre...@google.com, gre...@linuxfoundation.org, kai.he...@canonical.com, linux-...@vger.kernel.org, linu...@vger.kernel.org, ma...@mansr.com, one...@suse.com, syzkall...@googlegroups.com
On Tue, 17 Sep 2019, syzbot wrote:

> Hello,
>
> syzbot has tested the proposed patch but the reproducer still triggered
> crash:
> WARNING in sysfs_remove_group
>
> ------------[ cut here ]------------
> sysfs group 'power' not found for kobject 'radio0'

Andrey:

Is there any way to tell syzbot to run the reproducer but with only one
device instance (that is, only one dummy-hcd bus)?

Or can you a new, modified reproducer that will do this?

Alan Stern

Alan Stern

unread,
Sep 19, 2019, 10:03:11 AM9/19/19
to syzbot, syzkall...@googlegroups.com

#syz test: https://github.com/google/kasan.git f0df5c1b

drivers/base/power/sysfs.c | 7 ++-
drivers/media/usb/usbvision/usbvision-video.c | 58 ++++++++++++++++++++++++--
fs/sysfs/group.c | 12 +++++
3 files changed, 72 insertions(+), 5 deletions(-)

Index: usb-devel/drivers/media/usb/usbvision/usbvision-video.c
===================================================================
--- usb-devel.orig/drivers/media/usb/usbvision/usbvision-video.c
+++ usb-devel/drivers/media/usb/usbvision/usbvision-video.c
@@ -131,6 +131,25 @@ MODULE_LICENSE("GPL");
MODULE_VERSION(USBVISION_VERSION_STRING);
MODULE_ALIAS(DRIVER_ALIAS);

+#include <linux/kernfs.h>
+#include <linux/kobject.h>
+
+static void usbvision_check(struct usb_usbvision *usbvision, char *msg)
+{
+ struct kernfs_node *kn;
+
+ if (!video_is_registered(&usbvision->rdev)) {
+ dev_info(&usbvision->rdev.dev, "Not registered: %s\n", msg);
+ } else {
+ kn = kernfs_find_and_get(usbvision->rdev.dev.kobj.sd, "power");
+ if (kn) {
+ kernfs_put(kn);
+ dev_info(&usbvision->rdev.dev, "Power ok: %s\n", msg);
+ } else {
+ dev_err(&usbvision->rdev.dev, "Power gone: %s\n", msg);
+ }
+ }
+}

/*****************************************************************************/
/* SYSFS Code - Copied from the stv680.c usb module. */
@@ -314,6 +333,11 @@ static int usbvision_v4l2_open(struct fi
if (mutex_lock_interruptible(&usbvision->v4l2_lock))
return -ERESTARTSYS;

+ if (usbvision->remove_pending) {
+ err_code = -ENODEV;
+ goto unlock;
+ }
+ usbvision_check(usbvision, "v4l2 open");
if (usbvision->user) {
err_code = -EBUSY;
} else {
@@ -377,10 +401,12 @@ unlock:
static int usbvision_v4l2_close(struct file *file)
{
struct usb_usbvision *usbvision = video_drvdata(file);
+ int r;

PDEBUG(DBG_IO, "close");

mutex_lock(&usbvision->v4l2_lock);
+ usbvision_check(usbvision, "v4l2 close 1");
usbvision_audio_off(usbvision);
usbvision_restart_isoc(usbvision);
usbvision_stop_isoc(usbvision);
@@ -389,11 +415,13 @@ static int usbvision_v4l2_close(struct f
usbvision_frames_free(usbvision);
usbvision_empty_framequeues(usbvision);
usbvision_scratch_free(usbvision);
+ usbvision_check(usbvision, "v4l2 close 2");

usbvision->user--;
+ r = usbvision->remove_pending;
mutex_unlock(&usbvision->v4l2_lock);

- if (usbvision->remove_pending) {
+ if (r) {
printk(KERN_INFO "%s: Final disconnect\n", __func__);
usbvision_release(usbvision);
return 0;
@@ -453,6 +481,9 @@ static int vidioc_querycap(struct file *
{
struct usb_usbvision *usbvision = video_drvdata(file);

+ if (!usbvision->dev)
+ return -ENODEV;
+
strscpy(vc->driver, "USBVision", sizeof(vc->driver));
strscpy(vc->card,
usbvision_device_data[usbvision->dev_model].model_string,
@@ -1073,6 +1104,12 @@ static int usbvision_radio_open(struct f

if (mutex_lock_interruptible(&usbvision->v4l2_lock))
return -ERESTARTSYS;
+
+ if (usbvision->remove_pending) {
+ err_code = -ENODEV;
+ goto out;
+ }
+ usbvision_check(usbvision, "radio open");
err_code = v4l2_fh_open(file);
if (err_code)
goto out;
@@ -1105,21 +1142,25 @@ out:
static int usbvision_radio_close(struct file *file)
{
struct usb_usbvision *usbvision = video_drvdata(file);
+ int r;

PDEBUG(DBG_IO, "");

mutex_lock(&usbvision->v4l2_lock);
+ usbvision_check(usbvision, "radio close");
/* Set packet size to 0 */
usbvision->iface_alt = 0;
- usb_set_interface(usbvision->dev, usbvision->iface,
+ if (usbvision->dev)
+ usb_set_interface(usbvision->dev, usbvision->iface,
usbvision->iface_alt);

usbvision_audio_off(usbvision);
usbvision->radio = 0;
usbvision->user--;
+ r = usbvision->remove_pending;
mutex_unlock(&usbvision->v4l2_lock);

- if (usbvision->remove_pending) {
+ if (r) {
printk(KERN_INFO "%s: Final disconnect\n", __func__);
v4l2_fh_release(file);
usbvision_release(usbvision);
@@ -1233,10 +1274,13 @@ static void usbvision_vdev_init(struct u
static void usbvision_unregister_video(struct usb_usbvision *usbvision)
{
/* Radio Device: */
+ usbvision_check(usbvision, "unregister video");
if (video_is_registered(&usbvision->rdev)) {
PDEBUG(DBG_PROBE, "unregister %s [v4l2]",
video_device_node_name(&usbvision->rdev));
+ dev_info(&usbvision->rdev.dev, "Unregister\n");
video_unregister_device(&usbvision->rdev);
+ printk(KERN_INFO "Unregister done\n");
}

/* Video Device: */
@@ -1283,6 +1327,7 @@ static int usbvision_register_video(stru
usbvision->nr, video_device_node_name(&usbvision->rdev));
}
/* all done */
+ usbvision_check(usbvision, "register video");
return 0;

err_exit:
@@ -1346,6 +1391,7 @@ static void usbvision_release(struct usb
{
PDEBUG(DBG_PROBE, "");

+ usbvision_check(usbvision, "release");
usbvision->initialized = 0;

usbvision_remove_sysfs(&usbvision->vdev);
@@ -1551,6 +1597,7 @@ err_usb:
static void usbvision_disconnect(struct usb_interface *intf)
{
struct usb_usbvision *usbvision = to_usbvision(usb_get_intfdata(intf));
+ int u;

PDEBUG(DBG_PROBE, "");

@@ -1560,6 +1607,7 @@ static void usbvision_disconnect(struct
}

mutex_lock(&usbvision->v4l2_lock);
+ usbvision_check(usbvision, "disconnect 1");

/* At this time we ask to cancel outstanding URBs */
usbvision_stop_isoc(usbvision);
@@ -1567,13 +1615,15 @@ static void usbvision_disconnect(struct
v4l2_device_disconnect(&usbvision->v4l2_dev);
usbvision_i2c_unregister(usbvision);
usbvision->remove_pending = 1; /* Now all ISO data will be ignored */
+ u = usbvision->user;

usb_put_dev(usbvision->dev);
usbvision->dev = NULL; /* USB device is no more */

+ usbvision_check(usbvision, "disconnect 2");

syzbot

unread,
Sep 19, 2019, 10:14:02 AM9/19/19
to st...@rowland.harvard.edu, syzkall...@googlegroups.com
Hello,

syzbot has tested the proposed patch but the reproducer still triggered
crash:
WARNING in sysfs_create_file_ns

usb 5-1: USBVision[127]: video_register_device() failed
(null): Not registered: unregister video
------------[ cut here ]------------
WARNING: CPU: 0 PID: 5 at fs/sysfs/file.c:327
sysfs_create_file_ns.cold+0x11/0x1e fs/sysfs/file.c:327
Kernel panic - not syncing: panic_on_warn set ...
CPU: 0 PID: 5 Comm: kworker/0:0 Not tainted 5.3.0-rc7+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Workqueue: usb_hub_wq hub_event
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0xca/0x13e lib/dump_stack.c:113
panic+0x2a3/0x6da kernel/panic.c:219
__warn.cold+0x20/0x4a kernel/panic.c:576
report_bug+0x262/0x2a0 lib/bug.c:186
fixup_bug arch/x86/kernel/traps.c:179 [inline]
fixup_bug arch/x86/kernel/traps.c:174 [inline]
do_error_trap+0x12b/0x1e0 arch/x86/kernel/traps.c:272
do_invalid_op+0x32/0x40 arch/x86/kernel/traps.c:291
invalid_op+0x23/0x30 arch/x86/entry/entry_64.S:1028
RIP: 0010:sysfs_create_file_ns.cold+0x11/0x1e fs/sysfs/file.c:327
Code: 6b 08 41 bc ff 0f 00 00 e9 79 f1 ff ff 48 8b 7c 24 08 e8 b7 fb db ff
eb e5 e8 20 53 b5 ff 48 c7 c7 e0 bb d0 85 e8 9d f4 9f ff <0f> 0b 41 bd ea
ff ff ff e9 48 f9 ff ff e8 02 53 b5 ff 48 c7 c7 e0
RSP: 0018:ffff8881da1c71e8 EFLAGS: 00010282
RAX: 0000000000000024 RBX: ffff8881c1868390 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff81288ddd RDI: ffffed103b438e2f
RBP: ffffffff87556f00 R08: 0000000000000024 R09: fffffbfff11ad99a
R10: fffffbfff11ad999 R11: ffffffff88d6cccf R12: 1ffff1103b438e3e
R13: 0000000000000000 R14: dffffc0000000000 R15: ffff8881c18683c0
sysfs_create_file include/linux/sysfs.h:521 [inline]
device_create_file+0xe6/0x1d0 drivers/base/core.c:1559
usbvision_create_sysfs drivers/media/usb/usbvision/usbvision-video.c:271
[inline]
usbvision_probe.cold+0x1b6e/0x1e68
drivers/media/usb/usbvision/usbvision-video.c:1576
usb_probe_interface+0x305/0x7a0 drivers/usb/core/driver.c:361
really_probe+0x281/0x6d0 drivers/base/dd.c:548
driver_probe_device+0x101/0x1b0 drivers/base/dd.c:721
__device_attach_driver+0x1c2/0x220 drivers/base/dd.c:828
bus_for_each_drv+0x162/0x1e0 drivers/base/bus.c:454
__device_attach+0x217/0x360 drivers/base/dd.c:894
bus_probe_device+0x1e4/0x290 drivers/base/bus.c:514
device_add+0xae6/0x16f0 drivers/base/core.c:2165
usb_set_configuration+0xdf6/0x1670 drivers/usb/core/message.c:2023
generic_probe+0x9d/0xd5 drivers/usb/core/generic.c:210
usb_probe_device+0x99/0x100 drivers/usb/core/driver.c:266
really_probe+0x281/0x6d0 drivers/base/dd.c:548
driver_probe_device+0x101/0x1b0 drivers/base/dd.c:721
__device_attach_driver+0x1c2/0x220 drivers/base/dd.c:828
bus_for_each_drv+0x162/0x1e0 drivers/base/bus.c:454
__device_attach+0x217/0x360 drivers/base/dd.c:894
bus_probe_device+0x1e4/0x290 drivers/base/bus.c:514
device_add+0xae6/0x16f0 drivers/base/core.c:2165
usb_new_device.cold+0x6a4/0xe79 drivers/usb/core/hub.c:2536
hub_port_connect drivers/usb/core/hub.c:5098 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5213 [inline]
port_event drivers/usb/core/hub.c:5359 [inline]
hub_event+0x1b5c/0x3640 drivers/usb/core/hub.c:5441
process_one_work+0x92b/0x1530 kernel/workqueue.c:2269
process_scheduled_works kernel/workqueue.c:2331 [inline]
worker_thread+0x7ab/0xe20 kernel/workqueue.c:2417
kthread+0x318/0x420 kernel/kthread.c:255
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352
Kernel Offset: disabled
Rebooting in 86400 seconds..


Tested on:

commit: f0df5c1b usb-fuzzer: main usb gadget fuzzer driver
git tree: https://github.com/google/kasan.git
console output: https://syzkaller.appspot.com/x/log.txt?x=134403c9600000
kernel config: https://syzkaller.appspot.com/x/.config?x=5c6633fa4ed00be5
dashboard link: https://syzkaller.appspot.com/bug?extid=7fa38a608b1075dfd634
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
patch: https://syzkaller.appspot.com/x/patch.diff?x=15e5cbc9600000

Andrey Konovalov

unread,
Sep 19, 2019, 11:19:24 AM9/19/19
to Alan Stern, syzbot, Greg Kroah-Hartman, Kai Heng Feng, LKML, USB list, ma...@mansr.com, Oliver Neukum, syzkaller-bugs
AFAIU there two bugs here and you've fixed the first one, but the
second one gets triggered.

I think the second one got reported separately here:

https://syzkaller.appspot.com/bug?extid=5b9bba68c833c84a1135

That one has a reproducer with a single dummy-hcd, so you can try
running your debugging patch against that report.

I'll see if I can run it manually in the meantime.

Andrey Konovalov

unread,
Sep 19, 2019, 11:35:16 AM9/19/19
to Alan Stern, syzbot, Greg Kroah-Hartman, Kai Heng Feng, LKML, USB list, ma...@mansr.com, Oliver Neukum, syzkaller-bugs
Attaching kernel log after running the reproducer for this bug with a
single dummy-hcd and with your latest patch applied.
usbvision.log

Alan Stern

unread,
Sep 19, 2019, 4:21:23 PM9/19/19
to syzbot, syzkall...@googlegroups.com
#syz test: https://github.com/google/kasan.git f0df5c1b

drivers/media/usb/usbvision/usbvision-video.c | 63 ++++++++++++++++++++++++--
1 file changed, 59 insertions(+), 4 deletions(-)
+ usbvision_check(usbvision, "v4l2 open");
+ if (usbvision->remove_pending) {
+ err_code = -ENODEV;
+ goto unlock;
+ }
if (usbvision->user) {
err_code = -EBUSY;
} else {
@@ -363,6 +387,7 @@ unlock:
mutex_unlock(&usbvision->v4l2_lock);

PDEBUG(DBG_IO, "success");
+ pr_info("v4l2 open -> %d\n", err_code);
return err_code;
}

@@ -377,10 +402,13 @@ unlock:
static int usbvision_v4l2_close(struct file *file)
{
struct usb_usbvision *usbvision = video_drvdata(file);
+ int r;

PDEBUG(DBG_IO, "close");

+ usbvision_check(usbvision, "v4l2 close 1");
mutex_lock(&usbvision->v4l2_lock);
+ usbvision_check(usbvision, "v4l2 close 2");
usbvision_audio_off(usbvision);
usbvision_restart_isoc(usbvision);
usbvision_stop_isoc(usbvision);
@@ -389,11 +417,13 @@ static int usbvision_v4l2_close(struct f
usbvision_frames_free(usbvision);
usbvision_empty_framequeues(usbvision);
usbvision_scratch_free(usbvision);
+ usbvision_check(usbvision, "v4l2 close 3");

usbvision->user--;
+ r = usbvision->remove_pending;
mutex_unlock(&usbvision->v4l2_lock);

- if (usbvision->remove_pending) {
+ if (r) {
printk(KERN_INFO "%s: Final disconnect\n", __func__);
usbvision_release(usbvision);
return 0;
@@ -453,6 +483,9 @@ static int vidioc_querycap(struct file *
{
struct usb_usbvision *usbvision = video_drvdata(file);

+ if (!usbvision->dev)
+ return -ENODEV;
+
strscpy(vc->driver, "USBVision", sizeof(vc->driver));
strscpy(vc->card,
usbvision_device_data[usbvision->dev_model].model_string,
@@ -1073,6 +1106,12 @@ static int usbvision_radio_open(struct f

if (mutex_lock_interruptible(&usbvision->v4l2_lock))
return -ERESTARTSYS;
+
+ usbvision_check(usbvision, "radio open");
+ if (usbvision->remove_pending) {
+ err_code = -ENODEV;
+ goto out;
+ }
err_code = v4l2_fh_open(file);
if (err_code)
goto out;
@@ -1098,6 +1137,7 @@ static int usbvision_radio_open(struct f
}
out:
mutex_unlock(&usbvision->v4l2_lock);
+ pr_info("radio open -> %d\n", err_code);
return err_code;
}

@@ -1105,21 +1145,27 @@ out:
static int usbvision_radio_close(struct file *file)
{
struct usb_usbvision *usbvision = video_drvdata(file);
+ int r;

PDEBUG(DBG_IO, "");

+ usbvision_check(usbvision, "radio close 1");
mutex_lock(&usbvision->v4l2_lock);
+ usbvision_check(usbvision, "radio close 2");
/* Set packet size to 0 */
usbvision->iface_alt = 0;
- usb_set_interface(usbvision->dev, usbvision->iface,
+ if (usbvision->dev)
+ usb_set_interface(usbvision->dev, usbvision->iface,
usbvision->iface_alt);

usbvision_audio_off(usbvision);
usbvision->radio = 0;
+ usbvision_check(usbvision, "radio close 3");
usbvision->user--;
+ r = usbvision->remove_pending;
mutex_unlock(&usbvision->v4l2_lock);

- if (usbvision->remove_pending) {
+ if (r) {
printk(KERN_INFO "%s: Final disconnect\n", __func__);
v4l2_fh_release(file);
usbvision_release(usbvision);
@@ -1233,10 +1279,13 @@ static void usbvision_vdev_init(struct u
static void usbvision_unregister_video(struct usb_usbvision *usbvision)
{
/* Radio Device: */
+ usbvision_check(usbvision, "unregister video");
if (video_is_registered(&usbvision->rdev)) {
PDEBUG(DBG_PROBE, "unregister %s [v4l2]",
video_device_node_name(&usbvision->rdev));
+ dev_info(&usbvision->rdev.dev, "Unregister\n");
video_unregister_device(&usbvision->rdev);
+ printk(KERN_INFO "Unregister done\n");
}

/* Video Device: */
@@ -1283,6 +1332,7 @@ static int usbvision_register_video(stru
usbvision->nr, video_device_node_name(&usbvision->rdev));
}
/* all done */
+ usbvision_check(usbvision, "register video");
return 0;

err_exit:
@@ -1346,6 +1396,7 @@ static void usbvision_release(struct usb
{
PDEBUG(DBG_PROBE, "");

+ usbvision_check(usbvision, "release");
usbvision->initialized = 0;

usbvision_remove_sysfs(&usbvision->vdev);
@@ -1551,6 +1602,7 @@ err_usb:
static void usbvision_disconnect(struct usb_interface *intf)
{
struct usb_usbvision *usbvision = to_usbvision(usb_get_intfdata(intf));
+ int u;

PDEBUG(DBG_PROBE, "");

@@ -1560,6 +1612,7 @@ static void usbvision_disconnect(struct
}

mutex_lock(&usbvision->v4l2_lock);
+ usbvision_check(usbvision, "disconnect 1");

/* At this time we ask to cancel outstanding URBs */
usbvision_stop_isoc(usbvision);
@@ -1567,13 +1620,15 @@ static void usbvision_disconnect(struct

syzbot

unread,
Sep 19, 2019, 5:17:01 PM9/19/19
to st...@rowland.harvard.edu, syzkall...@googlegroups.com
Hello,

syzbot has tested the proposed patch and the reproducer did not trigger
crash:

Reported-and-tested-by:
syzbot+5b9bba...@syzkaller.appspotmail.com

Tested on:

commit: f0df5c1b usb-fuzzer: main usb gadget fuzzer driver
git tree: https://github.com/google/kasan.git
kernel config: https://syzkaller.appspot.com/x/.config?x=7b1689b83dfa890e
dashboard link: https://syzkaller.appspot.com/bug?extid=5b9bba68c833c84a1135
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
patch: https://syzkaller.appspot.com/x/patch.diff?x=13b0afb5600000

Note: testing is done by a robot and is best-effort only.

Alan Stern

unread,
Sep 24, 2019, 10:28:49 AM9/24/19
to syzbot, syzkall...@googlegroups.com
#syz test: https://github.com/google/kasan.git f0df5c1b

---
drivers/media/usb/usbvision/usbvision-video.c | 27 ++++++++++++++++++++++----
1 file changed, 23 insertions(+), 4 deletions(-)

Index: usb-devel/drivers/media/usb/usbvision/usbvision-video.c
===================================================================
--- usb-devel.orig/drivers/media/usb/usbvision/usbvision-video.c
+++ usb-devel/drivers/media/usb/usbvision/usbvision-video.c
@@ -314,6 +314,10 @@ static int usbvision_v4l2_open(struct fi
if (mutex_lock_interruptible(&usbvision->v4l2_lock))
return -ERESTARTSYS;

+ if (usbvision->remove_pending) {
+ err_code = -ENODEV;
+ goto unlock;
+ }
if (usbvision->user) {
err_code = -EBUSY;
} else {
@@ -377,6 +381,7 @@ unlock:
static int usbvision_v4l2_close(struct file *file)
{
struct usb_usbvision *usbvision = video_drvdata(file);
+ int r;

PDEBUG(DBG_IO, "close");

@@ -391,9 +396,10 @@ static int usbvision_v4l2_close(struct f
usbvision_scratch_free(usbvision);

usbvision->user--;
+ r = usbvision->remove_pending;
mutex_unlock(&usbvision->v4l2_lock);

- if (usbvision->remove_pending) {
+ if (r) {
printk(KERN_INFO "%s: Final disconnect\n", __func__);
usbvision_release(usbvision);
return 0;
@@ -453,6 +459,9 @@ static int vidioc_querycap(struct file *
{
struct usb_usbvision *usbvision = video_drvdata(file);

+ if (!usbvision->dev)
+ return -ENODEV;
+
strscpy(vc->driver, "USBVision", sizeof(vc->driver));
strscpy(vc->card,
usbvision_device_data[usbvision->dev_model].model_string,
@@ -1073,6 +1082,11 @@ static int usbvision_radio_open(struct f

if (mutex_lock_interruptible(&usbvision->v4l2_lock))
return -ERESTARTSYS;
+
+ if (usbvision->remove_pending) {
+ err_code = -ENODEV;
+ goto out;
+ }
err_code = v4l2_fh_open(file);
if (err_code)
goto out;
@@ -1105,21 +1119,24 @@ out:
static int usbvision_radio_close(struct file *file)
{
struct usb_usbvision *usbvision = video_drvdata(file);
+ int r;

PDEBUG(DBG_IO, "");

mutex_lock(&usbvision->v4l2_lock);
/* Set packet size to 0 */
usbvision->iface_alt = 0;
- usb_set_interface(usbvision->dev, usbvision->iface,
+ if (usbvision->dev)
+ usb_set_interface(usbvision->dev, usbvision->iface,
usbvision->iface_alt);

usbvision_audio_off(usbvision);
usbvision->radio = 0;
usbvision->user--;
+ r = usbvision->remove_pending;
mutex_unlock(&usbvision->v4l2_lock);

- if (usbvision->remove_pending) {
+ if (r) {
printk(KERN_INFO "%s: Final disconnect\n", __func__);
v4l2_fh_release(file);
usbvision_release(usbvision);
@@ -1551,6 +1568,7 @@ err_usb:
static void usbvision_disconnect(struct usb_interface *intf)
{
struct usb_usbvision *usbvision = to_usbvision(usb_get_intfdata(intf));
+ int u;

PDEBUG(DBG_PROBE, "");

@@ -1567,13 +1585,14 @@ static void usbvision_disconnect(struct
v4l2_device_disconnect(&usbvision->v4l2_dev);
usbvision_i2c_unregister(usbvision);
usbvision->remove_pending = 1; /* Now all ISO data will be ignored */
+ u = usbvision->user;

usb_put_dev(usbvision->dev);
usbvision->dev = NULL; /* USB device is no more */

syzbot

unread,
Sep 24, 2019, 10:48:01 AM9/24/19
to st...@rowland.harvard.edu, syzkall...@googlegroups.com
Hello,

syzbot has tested the proposed patch and the reproducer did not trigger
crash:

Reported-and-tested-by:
syzbot+5b9bba...@syzkaller.appspotmail.com

Tested on:

commit: f0df5c1b usb-fuzzer: main usb gadget fuzzer driver
git tree: https://github.com/google/kasan.git
kernel config: https://syzkaller.appspot.com/x/.config?x=7b1689b83dfa890e
dashboard link: https://syzkaller.appspot.com/bug?extid=5b9bba68c833c84a1135
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
patch: https://syzkaller.appspot.com/x/patch.diff?x=1215fc4d600000

Andrey Konovalov

unread,
Dec 13, 2019, 7:16:05 AM12/13/19
to syzbot, Alan Stern, Greg Kroah-Hartman, Kai Heng Feng, LKML, USB list, ma...@mansr.com, Oliver Neukum, syzkaller-bugs
On Mon, Sep 16, 2019 at 3:29 PM syzbot
<syzbot+7fa38a...@syzkaller.appspotmail.com> wrote:
>
> Hello,
>
> syzbot found the following crash on:
>
> HEAD commit: f0df5c1b usb-fuzzer: main usb gadget fuzzer driver
> git tree: https://github.com/google/kasan.git usb-fuzzer
> console output: https://syzkaller.appspot.com/x/log.txt?x=158b66f1600000
> kernel config: https://syzkaller.appspot.com/x/.config?x=5c6633fa4ed00be5
> dashboard link: https://syzkaller.appspot.com/bug?extid=7fa38a608b1075dfd634
> compiler: gcc (GCC) 9.0.0 20181231 (experimental)
> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=14f57db9600000
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=127b61a5600000
>
> IMPORTANT: if you fix the bug, please add the following tag to the commit:
> Reported-by: syzbot+7fa38a...@syzkaller.appspotmail.com
>
> usb 3-1: usbvision_write_reg: failed: error -2
> usbvision_set_audio: can't write iopin register for audio switching
> kasan: CONFIG_KASAN_INLINE enabled
> kasan: GPF could be caused by NULL-ptr deref or user memory access
> general protection fault: 0000 [#1] SMP KASAN
> CPU: 1 PID: 1955 Comm: v4l_id Not tainted 5.3.0-rc7+ #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
> Google 01/01/2011
> RIP: 0010:usb_set_interface+0x34/0xa50 drivers/usb/core/message.c:1362
> Code: fc 55 53 48 83 ec 40 89 54 24 18 89 74 24 10 e8 22 1c ef fd 49 8d 7c
> 24 48 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f
> 85 fb 08 00 00 49 8b 44 24 48 49 8d 7c 24 18 48 89
> RSP: 0018:ffff8881cb19fd50 EFLAGS: 00010206
> RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000000
> RDX: 0000000000000009 RSI: ffffffff834ebe7e RDI: 0000000000000048
> RBP: ffff8881cb8e4200 R08: ffffffff88d21878 R09: ffffed103971cb43
> R10: ffff8881cb19fdc8 R11: ffff8881cb8e5a17 R12: 0000000000000000
> R13: ffff8881cb8e5a10 R14: ffff8881cb8e4cc8 R15: ffff8881cb8e5178
> FS: 00007f4f60b6d700(0000) GS:ffff8881db300000(0000) knlGS:0000000000000000
> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00007f4f6060c330 CR3: 00000001cc3a8000 CR4: 00000000001406e0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> Call Trace:
> usbvision_radio_close+0x105/0x250
> drivers/media/usb/usbvision/usbvision-video.c:1114
> v4l2_release+0x2e7/0x390 drivers/media/v4l2-core/v4l2-dev.c:455
> __fput+0x2d7/0x840 fs/file_table.c:280
> task_work_run+0x13f/0x1c0 kernel/task_work.c:113
> tracehook_notify_resume include/linux/tracehook.h:188 [inline]
> exit_to_usermode_loop+0x1d2/0x200 arch/x86/entry/common.c:163
> prepare_exit_to_usermode arch/x86/entry/common.c:194 [inline]
> syscall_return_slowpath arch/x86/entry/common.c:274 [inline]
> do_syscall_64+0x45f/0x580 arch/x86/entry/common.c:299
> entry_SYSCALL_64_after_hwframe+0x49/0xbe
> RIP: 0033:0x7f4f6069b2b0
> Code: 40 75 0b 31 c0 48 83 c4 08 e9 0c ff ff ff 48 8d 3d c5 32 08 00 e8 c0
> 07 02 00 83 3d 45 a3 2b 00 00 75 10 b8 03 00 00 00 0f 05 <48> 3d 01 f0 ff
> ff 73 31 c3 48 83 ec 08 e8 ce 8a 01 00 48 89 04 24
> RSP: 002b:00007ffde2d50ee8 EFLAGS: 00000246 ORIG_RAX: 0000000000000003
> RAX: 0000000000000000 RBX: 0000000000000003 RCX: 00007f4f6069b2b0
> RDX: 00007f4f60951df0 RSI: 0000000000000001 RDI: 0000000000000003
> RBP: 0000000000000000 R08: 00007f4f60951df0 R09: 000000000000000a
> R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000400884
> R13: 00007ffde2d51040 R14: 0000000000000000 R15: 0000000000000000
> Modules linked in:
> ---[ end trace 62bd2b7512ab49ee ]---
> RIP: 0010:usb_set_interface+0x34/0xa50 drivers/usb/core/message.c:1362
> Code: fc 55 53 48 83 ec 40 89 54 24 18 89 74 24 10 e8 22 1c ef fd 49 8d 7c
> 24 48 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f
> 85 fb 08 00 00 49 8b 44 24 48 49 8d 7c 24 18 48 89
> RSP: 0018:ffff8881cb19fd50 EFLAGS: 00010206
> RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000000
> RDX: 0000000000000009 RSI: ffffffff834ebe7e RDI: 0000000000000048
> RBP: ffff8881cb8e4200 R08: ffffffff88d21878 R09: ffffed103971cb43
> R10: ffff8881cb19fdc8 R11: ffff8881cb8e5a17 R12: 0000000000000000
> R13: ffff8881cb8e5a10 R14: ffff8881cb8e4cc8 R15: ffff8881cb8e5178
> FS: 00007f4f60b6d700(0000) GS:ffff8881db300000(0000) knlGS:0000000000000000
> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00007f4f6060c330 CR3: 00000001cc3a8000 CR4: 00000000001406e0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
>
>
> ---
> This bug is generated by a bot. It may contain errors.
> See https://goo.gl/tpsmEJ for more information about syzbot.
> syzbot engineers can be reached at syzk...@googlegroups.com.
>
> syzbot will keep track of this bug report. See:
> https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
> syzbot can test patches for this bug, for details see:
> https://goo.gl/tpsmEJ#testing-patches

Let's retry here:
usbvision.patch

syzbot

unread,
Dec 13, 2019, 7:16:06 AM12/13/19
to Andrey Konovalov, andre...@google.com, gre...@linuxfoundation.org, kai.he...@canonical.com, linux-...@vger.kernel.org, linu...@vger.kernel.org, ma...@mansr.com, one...@suse.com, st...@rowland.harvard.edu, syzkall...@googlegroups.com
This bug is already marked as fixed. No point in testing.

Andrey Konovalov

unread,
Dec 13, 2019, 7:19:29 AM12/13/19
to syzbot, Greg Kroah-Hartman, Kai Heng Feng, LKML, USB list, ma...@mansr.com, Oliver Neukum, Alan Stern, syzkaller-bugs
Hm, that explains some of the weirdness. It doesn't explain though
neither why the patch was actually tested when Alan requested it nor
why syzbot sent no reply.

Alan Stern

unread,
Dec 13, 2019, 2:51:34 PM12/13/19
to Andrey Konovalov, syzbot, LKML, USB list, ma...@mansr.com, syzkaller-bugs
On Fri, 13 Dec 2019, Andrey Konovalov wrote:

> > > Let's retry here:
> >
> > > #syz test: https://github.com/google/kasan.git f0df5c1b
> >
> > This bug is already marked as fixed. No point in testing.
> >
>
> Hm, that explains some of the weirdness. It doesn't explain though
> neither why the patch was actually tested when Alan requested it nor
> why syzbot sent no reply.

In the meantime, is there any way to get syzbot to test the new patch
with the old reproducer? Perhaps tell it to re-open this bug?

Alan Stern

Andrey Konovalov

unread,
Dec 16, 2019, 9:59:16 AM12/16/19
to Alan Stern, syzbot, LKML, USB list, ma...@mansr.com, syzkaller-bugs
No, we can only test this manually now. I can run the reproducer for
you. Should I revert the fix for this bug and then apply your patch?
What's the expected result?

Alan Stern

unread,
Dec 16, 2019, 10:05:13 AM12/16/19
to Andrey Konovalov, syzbot, LKML, USB list, ma...@mansr.com, syzkaller-bugs
Please simply run the patch as it is, with no other changes. The
expected result is a use-after-free Read in usbvision_v4l2_open, just
as with c7b0ec009a216143df30.

Alan Stern

Andrey Konovalov

unread,
Dec 16, 2019, 10:24:31 AM12/16/19
to Alan Stern, syzbot, LKML, USB list, ma...@mansr.com, syzkaller-bugs
I've tried to run both the reproducer from this thread and the log
from the other one on 5.5-rc1 with your patch (and other USB fuzzing
patches) applied, but didn't get any crashes.

Thanks!

Dmitry Vyukov

unread,
Dec 17, 2019, 8:17:47 AM12/17/19
to Alan Stern, Andrey Konovalov, syzbot, LKML, USB list, ma...@mansr.com, syzkaller-bugs
I can't figure this out now.
According to the database, there was a test job for that bug from you
on Dec 10, it finished with some error and the result was mailed. But
I can't find it anywhere as well.

I've filed https://github.com/google/syzkaller/issues/1547
"dashboard/app: show jobs on bug page", which I think will be useful
and will shed some light on such cases and make it more transparent
for you, it will also show the result even if you did not receive it
over email.
Thanks
Reply all
Reply to author
Forward
0 new messages