WARNING in r871xu_dev_remove

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: eea39f24 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=163ae012600000
kernel config: https://syzkaller.appspot.com/x/.config?x=d0c62209eedfd54e
dashboard link: https://syzkaller.appspot.com/bug?extid=80899a8a8efe8968cde7
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1739cb0e600000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=154fcc2e600000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+80899a...@syzkaller.appspotmail.com

------------[ cut here ]------------
WARNING: CPU: 1 PID: 83 at net/core/dev.c:8167
rollback_registered_many.cold+0x41/0x1bc net/core/dev.c:8167
Kernel panic - not syncing: panic_on_warn set ...
CPU: 1 PID: 83 Comm: kworker/1:2 Not tainted 5.3.0-rc5+ #28
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:rollback_registered_many.cold+0x41/0x1bc net/core/dev.c:8167
Code: ff e8 c7 26 90 fc 48 c7 c7 40 ec 63 86 e8 24 c8 7a fc 0f 0b e9 93 be
ff ff e8 af 26 90 fc 48 c7 c7 40 ec 63 86 e8 0c c8 7a fc <0f> 0b 4c 89 e7
e8 f9 12 34 fd 31 ff 41 89 c4 89 c6 e8 bd 27 90 fc
RSP: 0018:ffff8881d938f6a8 EFLAGS: 00010286
RAX: 0000000000000024 RBX: ffff8881d2a10000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff81288cfd RDI: ffffed103b271ec7
RBP: ffff8881d938f7d8 R08: 0000000000000024 R09: fffffbfff11ad794
R10: fffffbfff11ad793 R11: ffffffff88d6bc9f R12: ffff8881d2a10070
R13: ffff8881d938f768 R14: dffffc0000000000 R15: 0000000000000000
rollback_registered+0xf2/0x1c0 net/core/dev.c:8243
unregister_netdevice_queue net/core/dev.c:9290 [inline]
unregister_netdevice_queue+0x1d7/0x2b0 net/core/dev.c:9283
unregister_netdevice include/linux/netdevice.h:2631 [inline]
unregister_netdev+0x18/0x20 net/core/dev.c:9331
r871xu_dev_remove+0xe2/0x215 drivers/staging/rtl8712/usb_intf.c:604
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
Kernel Offset: disabled
Rebooting in 86400 seconds..


---
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:
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syzbot can test patches for this bug, for details see:
https://goo.gl/tpsmEJ#testing-patches

[Oliver Neukum]

Am Donnerstag, den 22.08.2019, 07:28 -0700 schrieb syzbot:
> Hello,
>
> syzbot found the following crash on:
>
> HEAD commit: eea39f24 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=163ae012600000
> kernel config: https://syzkaller.appspot.com/x/.config?x=d0c62209eedfd54e
> dashboard link: https://syzkaller.appspot.com/bug?extid=80899a8a8efe8968cde7
> compiler: gcc (GCC) 9.0.0 20181231 (experimental)
> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1739cb0e600000
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=154fcc2e600000
>
> IMPORTANT: if you fix the bug, please add the following tag to the commit:
> Reported-by: syzbot+80899a...@syzkaller.appspotmail.com

#syz test: https://github.com/google/kasan.git eea39f24

From 4f21b5aabc448719aa612b9359d90a178cb485d8 Mon Sep 17 00:00:00 2001
From: Oliver Neukum <one...@suse.com>
Date: Thu, 22 Aug 2019 16:37:33 +0200
Subject: [PATCH] rtl8712: fix race between firmware failing to load and
disconnect

We have to wait for the attempt to load the firmware to finish
before we evaluate the result.

Reported-by: syzbot+80899a...@syzkaller.appspotmail.com
Signed-off-by: Oliver Neukum <one...@suse.com>
---
drivers/staging/rtl8712/hal_init.c | 3 ++-
drivers/staging/rtl8712/usb_intf.c | 8 ++++++--
2 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/drivers/staging/rtl8712/hal_init.c b/drivers/staging/rtl8712/hal_init.c
index 40145c0338e4..42c0a3c947f1 100644
--- a/drivers/staging/rtl8712/hal_init.c
+++ b/drivers/staging/rtl8712/hal_init.c
@@ -33,7 +33,6 @@ static void rtl871x_load_fw_cb(const struct firmware *firmware, void *context)
{
struct _adapter *adapter = context;

- complete(&adapter->rtl8712_fw_ready);
if (!firmware) {
struct usb_device *udev = adapter->dvobjpriv.pusbdev;
struct usb_interface *usb_intf = adapter->pusb_intf;
@@ -41,11 +40,13 @@ static void rtl871x_load_fw_cb(const struct firmware *firmware, void *context)
dev_err(&udev->dev, "r8712u: Firmware request failed\n");
usb_put_dev(udev);
usb_set_intfdata(usb_intf, NULL);
+ complete(&adapter->rtl8712_fw_ready);
return;
}
adapter->fw = firmware;
/* firmware available - start netdev */
register_netdev(adapter->pnetdev);
+ complete(&adapter->rtl8712_fw_ready);
}

static const char firmware_file[] = "rtlwifi/rtl8712u.bin";
diff --git a/drivers/staging/rtl8712/usb_intf.c b/drivers/staging/rtl8712/usb_intf.c
index d0daae0b8299..8d7b57073592 100644
--- a/drivers/staging/rtl8712/usb_intf.c
+++ b/drivers/staging/rtl8712/usb_intf.c
@@ -595,10 +595,13 @@ static void r871xu_dev_remove(struct usb_interface *pusb_intf)
if (pnetdev) {
struct _adapter *padapter = netdev_priv(pnetdev);

- usb_set_intfdata(pusb_intf, NULL);
- release_firmware(padapter->fw);
/* never exit with a firmware callback pending */
wait_for_completion(&padapter->rtl8712_fw_ready);
+ pnetdev = usb_get_intfdata(pusb_intf);
+ usb_set_intfdata(pusb_intf, NULL);
+ if (!pnetdev)
+ goto raced_with_firmware_failure;
+ release_firmware(padapter->fw);
if (drvpriv.drv_registered)
padapter->surprise_removed = true;
unregister_netdev(pnetdev); /* will call netdev_close() */
@@ -609,6 +612,7 @@ static void r871xu_dev_remove(struct usb_interface *pusb_intf)
r871x_dev_unload(padapter);
r8712_free_drv_sw(padapter);

+raced_with_firmware_failure:
/* decrease the reference count of the usb device structure
* when disconnect
*/
--
2.16.4

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer still triggered
crash:
KASAN: use-after-free Read in device_release_driver_internal

==================================================================
BUG: KASAN: use-after-free in __mutex_lock_common
kernel/locking/mutex.c:912 [inline]
BUG: KASAN: use-after-free in __mutex_lock+0xf23/0x1360
kernel/locking/mutex.c:1077
Read of size 8 at addr ffff8881d644bd78 by task kworker/0:4/2855

CPU: 0 PID: 2855 Comm: kworker/0:4 Not tainted 5.3.0-rc5+ #1

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

print_address_description+0x6a/0x32c mm/kasan/report.c:351
__kasan_report.cold+0x1a/0x33 mm/kasan/report.c:482
kasan_report+0xe/0x12 mm/kasan/common.c:612
__mutex_lock_common kernel/locking/mutex.c:912 [inline]
__mutex_lock+0xf23/0x1360 kernel/locking/mutex.c:1077
device_release_driver_internal+0x23/0x500 drivers/base/dd.c:1162

bus_remove_device+0x2dc/0x4a0 drivers/base/bus.c:556
device_del+0x420/0xb10 drivers/base/core.c:2339

usb_disconnect+0x4c3/0x8d0 drivers/usb/core/hub.c:2225

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

worker_thread+0x96/0xe20 kernel/workqueue.c:2415

kthread+0x318/0x420 kernel/kthread.c:255
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352

Allocated by task 12:
save_stack+0x1b/0x80 mm/kasan/common.c:69
set_track mm/kasan/common.c:77 [inline]
__kasan_kmalloc mm/kasan/common.c:487 [inline]
__kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:460
kmalloc include/linux/slab.h:552 [inline]
kzalloc include/linux/slab.h:748 [inline]
usb_alloc_dev+0x51/0xf95 drivers/usb/core/usb.c:583
hub_port_connect drivers/usb/core/hub.c:5004 [inline]

hub_port_connect_change drivers/usb/core/hub.c:5213 [inline]
port_event drivers/usb/core/hub.c:5359 [inline]

hub_event+0x15c0/0x3640 drivers/usb/core/hub.c:5441
process_one_work+0x92b/0x1530 kernel/workqueue.c:2269
worker_thread+0x96/0xe20 kernel/workqueue.c:2415

kthread+0x318/0x420 kernel/kthread.c:255
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352

Freed by task 2855:
save_stack+0x1b/0x80 mm/kasan/common.c:69
set_track mm/kasan/common.c:77 [inline]
__kasan_slab_free+0x130/0x180 mm/kasan/common.c:449
slab_free_hook mm/slub.c:1423 [inline]
slab_free_freelist_hook mm/slub.c:1474 [inline]
slab_free mm/slub.c:3016 [inline]
kfree+0xe4/0x2f0 mm/slub.c:3957
device_release+0x71/0x200 drivers/base/core.c:1064
kobject_cleanup lib/kobject.c:693 [inline]
kobject_release lib/kobject.c:722 [inline]
kref_put include/linux/kref.h:65 [inline]
kobject_put+0x171/0x280 lib/kobject.c:739
put_device+0x1b/0x30 drivers/base/core.c:2264
klist_put+0xce/0x170 lib/klist.c:221
bus_remove_device+0x3a4/0x4a0 drivers/base/bus.c:552
device_del+0x420/0xb10 drivers/base/core.c:2339
usb_disconnect+0x4c3/0x8d0 drivers/usb/core/hub.c:2225

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

worker_thread+0x96/0xe20 kernel/workqueue.c:2415

kthread+0x318/0x420 kernel/kthread.c:255
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352

The buggy address belongs to the object at ffff8881d644bb80
which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 504 bytes inside of
2048-byte region [ffff8881d644bb80, ffff8881d644c380)
The buggy address belongs to the page:
page:ffffea0007591200 refcount:1 mapcount:0 mapping:ffff8881da00c000
index:0xffff8881d6448000 compound_mapcount: 0
flags: 0x200000000010200(slab|head)
raw: 0200000000010200 ffffea000760ac00 0000000200000002 ffff8881da00c000
raw: ffff8881d6448000 00000000800f000a 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffff8881d644bc00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8881d644bc80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> ffff8881d644bd00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff8881d644bd80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8881d644be00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================


Tested on:

commit: eea39f24 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=1018661e600000
kernel config: https://syzkaller.appspot.com/x/.config?x=d0c62209eedfd54e

compiler: gcc (GCC) 9.0.0 20181231 (experimental)

patch: https://syzkaller.appspot.com/x/patch.diff?x=1425bc2e600000