general protection fault in tower_disconnect

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 08a02f95 USB: add RESET_RESUME quirk for Snapscan 1212
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing
console output: https://syzkaller.appspot.com/x/log.txt?x=1435927b500000
kernel config: https://syzkaller.appspot.com/x/.config?x=d24ee9ecd7ce968e
dashboard link: https://syzkaller.appspot.com/bug?extid=9be25235b7a69b24d117
compiler: gcc (GCC) 10.1.0-syz 20200507
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=15145f07500000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=16b99413500000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+9be252...@syzkaller.appspotmail.com

usb 1-1: USB disconnect, device number 2
general protection fault, probably for non-canonical address 0xdffffc0000000013: 0000 [#1] SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000098-0x000000000000009f]
CPU: 0 PID: 7 Comm: kworker/0:1 Not tainted 5.10.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: usb_hub_wq hub_event
RIP: 0010:tower_disconnect+0x53/0x360 drivers/usb/misc/legousbtower.c:848
Code: 03 80 3c 02 00 0f 85 15 03 00 00 48 8b ab a8 00 00 00 48 b8 00 00 00 00 00 fc ff df 48 8d bd 98 00 00 00 48 89 fa 48 c1 ea 03 <0f> b6 04 02 84 c0 74 06 0f 8e 7b 02 00 00 48 c7 c6 40 07 bb 87 48
RSP: 0018:ffffc9000007f7c0 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: ffff888117ec0000 RCX: ffffffff8381f807
RDX: 0000000000000013 RSI: ffffffff83bab792 RDI: 0000000000000098
RBP: 0000000000000000 R08: 0000000000000001 R09: ffffffff898cc4ef
R10: 0000000000000002 R11: 0000000000000000 R12: ffff888117ec0090
R13: ffff888117ec0078 R14: ffff888117ec0030 R15: ffff888117ec0098
FS: 0000000000000000(0000) GS:ffff8881f6a00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f557af47550 CR3: 00000001090f3000 CR4: 00000000001506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
usb_unbind_interface+0x1d8/0x8d0 drivers/usb/core/driver.c:458
__device_release_driver+0x3bd/0x6f0 drivers/base/dd.c:1154
device_release_driver_internal drivers/base/dd.c:1185 [inline]
device_release_driver+0x26/0x40 drivers/base/dd.c:1208
bus_remove_device+0x2eb/0x5a0 drivers/base/bus.c:533
device_del+0x502/0xec0 drivers/base/core.c:3115
usb_disable_device+0x35b/0x7b0 drivers/usb/core/message.c:1413
usb_disconnect.cold+0x27d/0x780 drivers/usb/core/hub.c:2218
hub_port_connect drivers/usb/core/hub.c:5074 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5363 [inline]
port_event drivers/usb/core/hub.c:5509 [inline]
hub_event+0x1c8a/0x42d0 drivers/usb/core/hub.c:5591
process_one_work+0x933/0x1520 kernel/workqueue.c:2272
worker_thread+0x64c/0x1120 kernel/workqueue.c:2418
kthread+0x38c/0x460 kernel/kthread.c:292
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296
Modules linked in:
---[ end trace 5aeb1d199be5d5f2 ]---
RIP: 0010:tower_disconnect+0x53/0x360 drivers/usb/misc/legousbtower.c:848
Code: 03 80 3c 02 00 0f 85 15 03 00 00 48 8b ab a8 00 00 00 48 b8 00 00 00 00 00 fc ff df 48 8d bd 98 00 00 00 48 89 fa 48 c1 ea 03 <0f> b6 04 02 84 c0 74 06 0f 8e 7b 02 00 00 48 c7 c6 40 07 bb 87 48
RSP: 0018:ffffc9000007f7c0 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: ffff888117ec0000 RCX: ffffffff8381f807
RDX: 0000000000000013 RSI: ffffffff83bab792 RDI: 0000000000000098
RBP: 0000000000000000 R08: 0000000000000001 R09: ffffffff898cc4ef
R10: 0000000000000002 R11: 0000000000000000 R12: ffff888117ec0090
R13: ffff888117ec0078 R14: ffff888117ec0030 R15: ffff888117ec0098
FS: 0000000000000000(0000) GS:ffff8881f6a00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f557af47550 CR3: 00000001090f3000 CR4: 00000000001506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


---
This report 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 issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
syzbot can test patches for this issue, for details see:
https://goo.gl/tpsmEJ#testing-patches

[Alan Stern]

This is a simple thinko.

Alan Stern

#syz test: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 08a02f95

Index: usb-devel/drivers/usb/misc/legousbtower.c
===================================================================
--- usb-devel.orig/drivers/usb/misc/legousbtower.c
+++ usb-devel/drivers/usb/misc/legousbtower.c
@@ -797,7 +797,7 @@ static int tower_probe(struct usb_interf
&get_version_reply,
sizeof(get_version_reply),
1000, GFP_KERNEL);
- if (!result) {
+ if (result) {
dev_err(idev, "get version request failed: %d\n", result);
retval = result;
goto error;

[syzbot]

want 2 args (repo, branch), got 3

>
> Index: usb-devel/drivers/usb/misc/legousbtower.c
> ===================================================================
> --- usb-devel.orig/drivers/usb/misc/legousbtower.c
> +++ usb-devel/drivers/usb/misc/legousbtower.c
> @@ -797,7 +797,7 @@ static int tower_probe(struct usb_interf
> &get_version_reply,
> sizeof(get_version_reply),
> 1000, GFP_KERNEL);
> - if (!result) {
> + if (result) {
> dev_err(idev, "get version request failed: %d\n", result);
> retval = result;
> goto error;
>

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[syzbot]

want 2 args (repo, branch), got 3

>

[Alan Stern]

And there was one in my response. Sigh.

Alan Stern

#syz test: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git 08a02f95

[syzbot]

Hello,

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

Reported-and-tested-by: syzbot+9be252...@syzkaller.appspotmail.com

Tested on:

commit: 08a02f95 USB: add RESET_RESUME quirk for Snapscan 1212
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git

kernel config: https://syzkaller.appspot.com/x/.config?x=d24ee9ecd7ce968e
dashboard link: https://syzkaller.appspot.com/bug?extid=9be25235b7a69b24d117
compiler: gcc (GCC) 10.1.0-syz 20200507

patch: https://syzkaller.appspot.com/x/patch.diff?x=1406a80f500000

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

[Alan Stern]

Commit d9f0d82f06c6 ("USB: legousbtower: use usb_control_msg_recv()")
contained an elementary logical error. The check of the return code
from the new usb_control_msg_recv() function was inverted.

Reported-and-tested-by: syzbot+9be252...@syzkaller.appspotmail.com
Signed-off-by: Alan Stern <st...@rowland.harvard.edu>

---


[as1950]


drivers/usb/misc/legousbtower.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)