Re: [syzbot] INFO: task hung in usb_get_descriptor

Re: [syzbot] INFO: task hung in usb_get_descriptor

[syzbot]

syzbot suspects this issue was fixed by commit:

commit 363eaa3a450abb4e63bd6e3ad79d1f7a0f717814
Author: Shuah Khan <skhan@linuxfoundation.org>
Date:   Tue Mar 30 01:36:51 2021 +0000

    usbip: synchronize event handler with sysfs code paths

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=1616e872700000
start commit:   4fa56ad0d12e Merge tag 'for-linus' of git://git.kernel.org..
git tree:       upstream
kernel config:  https://syzkaller.appspot.com/x/.config?x=144ecdb0be3abc07
dashboard link: https://syzkaller.appspot.com/bug?extid=31ae6d17d115e980fd14
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=12548d11d00000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=13ec77e9d00000

If the result looks correct, please mark the issue as fixed by replying with:

#syz fix: usbip: synchronize event handler with sysfs code paths

For information about bisection process see: https://goo.gl/tpsmEJ#bisection

Re: [syzbot] INFO: task hung in usb_get_descriptor

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
KASAN: null-ptr-deref Write in vhci_shutdown_connection

==================================================================
BUG: KASAN: null-ptr-deref in instrument_atomic_write include/linux/instrumented.h:71 [inline]
BUG: KASAN: null-ptr-deref in atomic_fetch_add_relaxed include/asm-generic/atomic-instrumented.h:142 [inline]
BUG: KASAN: null-ptr-deref in refcount_add include/linux/refcount.h:201 [inline]
BUG: KASAN: null-ptr-deref in refcount_inc include/linux/refcount.h:241 [inline]
BUG: KASAN: null-ptr-deref in get_task_struct include/linux/sched/task.h:104 [inline]
BUG: KASAN: null-ptr-deref in kthread_stop+0x90/0x810 kernel/kthread.c:591
Write of size 4 at addr 000000000000001c by task kworker/u4:4/186

CPU: 0 PID: 186 Comm: kworker/u4:4 Not tainted 5.9.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: usbip_event event_handler
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x107/0x16e lib/dump_stack.c:118
 __kasan_report mm/kasan/report.c:517 [inline]
 kasan_report.cold+0x5/0x37 mm/kasan/report.c:530
 check_memory_region_inline mm/kasan/generic.c:186 [inline]
 check_memory_region+0x13d/0x180 mm/kasan/generic.c:192
 instrument_atomic_write include/linux/instrumented.h:71 [inline]
 atomic_fetch_add_relaxed include/asm-generic/atomic-instrumented.h:142 [inline]
 refcount_add include/linux/refcount.h:201 [inline]
 refcount_inc include/linux/refcount.h:241 [inline]
 get_task_struct include/linux/sched/task.h:104 [inline]
 kthread_stop+0x90/0x810 kernel/kthread.c:591
 vhci_shutdown_connection+0x17f/0x360 drivers/usb/usbip/vhci_hcd.c:1015
 event_handler+0x1f0/0x4f0 drivers/usb/usbip/usbip_event.c:78
 process_one_work+0x86c/0x16a0 kernel/workqueue.c:2269
 worker_thread+0x64c/0x1120 kernel/workqueue.c:2415
 kthread+0x3b5/0x4a0 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294
==================================================================
Kernel panic - not syncing: panic_on_warn set ...
CPU: 0 PID: 186 Comm: kworker/u4:4 Tainted: G    B             5.9.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: usbip_event event_handler
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x107/0x16e lib/dump_stack.c:118
 panic+0x393/0x7d3 kernel/panic.c:231
 end_report+0x4d/0x53 mm/kasan/report.c:104
 __kasan_report mm/kasan/report.c:520 [inline]
 kasan_report.cold+0xd/0x37 mm/kasan/report.c:530
 check_memory_region_inline mm/kasan/generic.c:186 [inline]
 check_memory_region+0x13d/0x180 mm/kasan/generic.c:192
 instrument_atomic_write include/linux/instrumented.h:71 [inline]
 atomic_fetch_add_relaxed include/asm-generic/atomic-instrumented.h:142 [inline]
 refcount_add include/linux/refcount.h:201 [inline]
 refcount_inc include/linux/refcount.h:241 [inline]
 get_task_struct include/linux/sched/task.h:104 [inline]
 kthread_stop+0x90/0x810 kernel/kthread.c:591
 vhci_shutdown_connection+0x17f/0x360 drivers/usb/usbip/vhci_hcd.c:1015
 event_handler+0x1f0/0x4f0 drivers/usb/usbip/usbip_event.c:78
 process_one_work+0x86c/0x16a0 kernel/workqueue.c:2269
 worker_thread+0x64c/0x1120 kernel/workqueue.c:2415
 kthread+0x3b5/0x4a0 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294
Kernel Offset: disabled
Rebooting in 86400 seconds..


Tested on:

commit:         d3d45f82 Merge tag 'pinctrl-v5.9-2' of git://git.kerne..
git tree:       https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/
console output: https://syzkaller.appspot.com/x/log.txt?x=125b4faa700000
kernel config:  https://syzkaller.appspot.com/x/.config?x=c4f7c05cb42b5045
dashboard link: https://syzkaller.appspot.com/bug?extid=31ae6d17d115e980fd14
compiler:       gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
patch:          https://syzkaller.appspot.com/x/patch.diff?x=1359552c700000

Re: [syzbot] INFO: task hung in usb_get_descriptor

[syzbot]

Hello,

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

Reported-and-tested-by: syzbot+31ae6d17d115e980fd14@syzkaller.appspotmail.com

Tested on:

commit:         b81b1829 Merge tag 'scsi-fixes' of git://git.kernel.or..
git tree:       upstream
kernel config:  https://syzkaller.appspot.com/x/.config?x=d94e196c4f68081d
dashboard link: https://syzkaller.appspot.com/bug?extid=31ae6d17d115e980fd14
compiler:       gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2

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

Re: [syzbot] INFO: task hung in usb_get_descriptor

[Dmitry Vyukov]

On Sat, 12 Feb 2022 at 23:43, syzbot
<syzbot+31ae6d17d115e980fd14@syzkaller.appspotmail.com> wrote:
>
> syzbot suspects this issue was fixed by commit:
>
> commit 363eaa3a450abb4e63bd6e3ad79d1f7a0f717814
> Author: Shuah Khan <skhan@linuxfoundation.org>
> Date:   Tue Mar 30 01:36:51 2021 +0000
>
>     usbip: synchronize event handler with sysfs code paths
>
> bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=1616e872700000
> start commit:   4fa56ad0d12e Merge tag 'for-linus' of git://git.kernel.org..
> git tree:       upstream
> kernel config:  https://syzkaller.appspot.com/x/.config?x=144ecdb0be3abc07
> dashboard link: https://syzkaller.appspot.com/bug?extid=31ae6d17d115e980fd14
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=12548d11d00000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=13ec77e9d00000
>
> If the result looks correct, please mark the issue as fixed by replying with:
>
> #syz fix: usbip: synchronize event handler with sysfs code paths

Based on subsystem and commit subject looks legit:

#syz fix: usbip: synchronize event handler with sysfs code paths