* [syzbot] WARNING: locking bug in umh_complete
@ 2023-01-26 22:27 syzbot
0 siblings, 0 replies; 2+ messages in thread
From: syzbot @ 2023-01-26 22:27 UTC (permalink / raw)
To: linux-kernel, mcgrof, netdev, syzkaller-bugs
Hello,
syzbot found the following issue on:
HEAD commit: 71ab9c3e2253 net: fix UaF in netns ops registration error ..
git tree: net
console output: https://syzkaller.appspot.com/x/log.txt?x=10f86a56480000
kernel config: https://syzkaller.appspot.com/x/.config?x=899d86a7610a0ea0
dashboard link: https://syzkaller.appspot.com/bug?extid=6cd18e123583550cf469
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/54c953096fdb/disk-71ab9c3e.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/644d72265810/vmlinux-71ab9c3e.xz
kernel image: https://storage.googleapis.com/syzbot-assets/16e994579ca5/bzImage-71ab9c3e.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+6cd18e123583550cf469@syzkaller.appspotmail.com
------------[ cut here ]------------
DEBUG_LOCKS_WARN_ON(1)
WARNING: CPU: 0 PID: 46 at kernel/locking/lockdep.c:231 hlock_class kernel/locking/lockdep.c:231 [inline]
WARNING: CPU: 0 PID: 46 at kernel/locking/lockdep.c:231 hlock_class kernel/locking/lockdep.c:220 [inline]
WARNING: CPU: 0 PID: 46 at kernel/locking/lockdep.c:231 check_wait_context kernel/locking/lockdep.c:4729 [inline]
WARNING: CPU: 0 PID: 46 at kernel/locking/lockdep.c:231 __lock_acquire+0x13ae/0x56d0 kernel/locking/lockdep.c:5005
Modules linked in:
CPU: 0 PID: 46 Comm: kworker/u4:3 Not tainted 6.2.0-rc4-syzkaller-00191-g71ab9c3e2253 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/12/2023
Workqueue: events_unbound call_usermodehelper_exec_work
RIP: 0010:hlock_class kernel/locking/lockdep.c:231 [inline]
RIP: 0010:hlock_class kernel/locking/lockdep.c:220 [inline]
RIP: 0010:check_wait_context kernel/locking/lockdep.c:4729 [inline]
RIP: 0010:__lock_acquire+0x13ae/0x56d0 kernel/locking/lockdep.c:5005
Code: 08 84 d2 0f 85 56 41 00 00 8b 15 55 7b 0f 0d 85 d2 0f 85 d5 fd ff ff 48 c7 c6 c0 51 4c 8a 48 c7 c7 20 4b 4c 8a e8 92 e1 5b 08 <0f> 0b 31 ed e9 50 f0 ff ff 48 c7 c0 a8 2b 73 8e 48 ba 00 00 00 00
RSP: 0018:ffffc90000b77a30 EFLAGS: 00010082
RAX: 0000000000000000 RBX: ffff88801272a778 RCX: 0000000000000000
RDX: ffff888012729d40 RSI: ffffffff8166822c RDI: fffff5200016ef38
RBP: 0000000000001b2c R08: 0000000000000005 R09: 0000000000000000
R10: 0000000080000001 R11: 0000000000000001 R12: ffff88801272a7c8
R13: ffff888012729d40 R14: ffffc9000397fb28 R15: 0000000000040000
FS: 0000000000000000(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fa5a95e81d0 CR3: 00000000284d2000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
lock_acquire kernel/locking/lockdep.c:5668 [inline]
lock_acquire+0x1e3/0x630 kernel/locking/lockdep.c:5633
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0x3d/0x60 kernel/locking/spinlock.c:162
complete+0x1d/0x1f0 kernel/sched/completion.c:32
umh_complete+0x32/0x90 kernel/umh.c:59
call_usermodehelper_exec_sync kernel/umh.c:144 [inline]
call_usermodehelper_exec_work+0x115/0x180 kernel/umh.c:167
process_one_work+0x9bf/0x1710 kernel/workqueue.c:2289
worker_thread+0x669/0x1090 kernel/workqueue.c:2436
kthread+0x2e8/0x3a0 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308
</TASK>
---
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 syzkaller@googlegroups.com.
syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [syzbot] WARNING: locking bug in umh_complete
[not found] <20230127014137.4906-1-hdanton@sina.com>
@ 2023-02-03 10:22 ` Tetsuo Handa
0 siblings, 0 replies; 2+ messages in thread
From: Tetsuo Handa @ 2023-02-03 10:22 UTC (permalink / raw)
To: Hillf Danton, Peter Zijlstra (Intel), Ingo Molnar,
Rafael J. Wysocki
Cc: linux-kernel, mcgrof, Linus Torvalds, syzkaller-bugs, syzbot
On 2023/01/27 10:41, Hillf Danton wrote:
> On Thu, 26 Jan 2023 14:27:51 -0800
>> syzbot found the following issue on:
>>
>> HEAD commit: 71ab9c3e2253 net: fix UaF in netns ops registration error ..
>> git tree: net
>> console output: https://syzkaller.appspot.com/x/log.txt?x=10f86a56480000
>> kernel config: https://syzkaller.appspot.com/x/.config?x=899d86a7610a0ea0
>> dashboard link: https://syzkaller.appspot.com/bug?extid=6cd18e123583550cf469
>> compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
>>
>> Unfortunately, I don't have any reproducer for this issue yet.
>>
>> Downloadable assets:
>> disk image: https://storage.googleapis.com/syzbot-assets/54c953096fdb/disk-71ab9c3e.raw.xz
>> vmlinux: https://storage.googleapis.com/syzbot-assets/644d72265810/vmlinux-71ab9c3e.xz
>> kernel image: https://storage.googleapis.com/syzbot-assets/16e994579ca5/bzImage-71ab9c3e.xz
>>
>> IMPORTANT: if you fix the issue, please add the following tag to the commit:
>> Reported-by: syzbot+6cd18e123583550cf469@syzkaller.appspotmail.com
>>
>> ------------[ cut here ]------------
>> DEBUG_LOCKS_WARN_ON(1)
>> WARNING: CPU: 0 PID: 46 at kernel/locking/lockdep.c:231 hlock_class kernel/locking/lockdep.c:231 [inline]
>> WARNING: CPU: 0 PID: 46 at kernel/locking/lockdep.c:231 hlock_class kernel/locking/lockdep.c:220 [inline]
>> WARNING: CPU: 0 PID: 46 at kernel/locking/lockdep.c:231 check_wait_context kernel/locking/lockdep.c:4729 [inline]
>> WARNING: CPU: 0 PID: 46 at kernel/locking/lockdep.c:231 __lock_acquire+0x13ae/0x56d0 kernel/locking/lockdep.c:5005
>> Modules linked in:
>> CPU: 0 PID: 46 Comm: kworker/u4:3 Not tainted 6.2.0-rc4-syzkaller-00191-g71ab9c3e2253 #0
>> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/12/2023
>> Workqueue: events_unbound call_usermodehelper_exec_work
>> RIP: 0010:hlock_class kernel/locking/lockdep.c:231 [inline]
>> RIP: 0010:hlock_class kernel/locking/lockdep.c:220 [inline]
>> RIP: 0010:check_wait_context kernel/locking/lockdep.c:4729 [inline]
>> RIP: 0010:__lock_acquire+0x13ae/0x56d0 kernel/locking/lockdep.c:5005
>> Code: 08 84 d2 0f 85 56 41 00 00 8b 15 55 7b 0f 0d 85 d2 0f 85 d5 fd ff ff 48 c7 c6 c0 51 4c 8a 48 c7 c7 20 4b 4c 8a e8 92 e1 5b 08 <0f> 0b 31 ed e9 50 f0 ff ff 48 c7 c0 a8 2b 73 8e 48 ba 00 00 00 00
>> RSP: 0018:ffffc90000b77a30 EFLAGS: 00010082
>> RAX: 0000000000000000 RBX: ffff88801272a778 RCX: 0000000000000000
>> RDX: ffff888012729d40 RSI: ffffffff8166822c RDI: fffff5200016ef38
>> RBP: 0000000000001b2c R08: 0000000000000005 R09: 0000000000000000
>> R10: 0000000080000001 R11: 0000000000000001 R12: ffff88801272a7c8
>> R13: ffff888012729d40 R14: ffffc9000397fb28 R15: 0000000000040000
>> FS: 0000000000000000(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
>> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>> CR2: 00007fa5a95e81d0 CR3: 00000000284d2000 CR4: 00000000003506f0
>> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
>> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
>> Call Trace:
>> <TASK>
>> lock_acquire kernel/locking/lockdep.c:5668 [inline]
>> lock_acquire+0x1e3/0x630 kernel/locking/lockdep.c:5633
>> __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
>> _raw_spin_lock_irqsave+0x3d/0x60 kernel/locking/spinlock.c:162
>> complete+0x1d/0x1f0 kernel/sched/completion.c:32
>> umh_complete+0x32/0x90 kernel/umh.c:59
>> call_usermodehelper_exec_sync kernel/umh.c:144 [inline]
>> call_usermodehelper_exec_work+0x115/0x180 kernel/umh.c:167
>> process_one_work+0x9bf/0x1710 kernel/workqueue.c:2289
>> worker_thread+0x669/0x1090 kernel/workqueue.c:2436
>> kthread+0x2e8/0x3a0 kernel/kthread.c:376
>> ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308
>> </TASK>
>
> This is an interesting case - given done initialized on stack, no garbage
> should have been detected by lockdep.
>
> One explanation to the report is uaf on the waker side, and it can be
> tested with the diff below when a reproducer is available.
>
> Hillf
>
> --- a/kernel/umh.c
> +++ b/kernel/umh.c
> @@ -452,6 +452,12 @@ int call_usermodehelper_exec(struct subp
> /* umh_complete() will see NULL and free sub_info */
> if (xchg(&sub_info->complete, NULL))
> goto unlock;
> + else {
> + /* wait for umh_complete() to finish in a bid to avoid
> + * uaf because done is destructed
> + */
> + wait_for_completion(&done);
> + }
> }
>
> wait_done:
> --
Yes, this bug is caused by commit f5d39b020809 ("freezer,sched: Rewrite core freezer
logic"), for that commit for unknown reason omits wait_for_completion(&done) call
when wait_for_completion_state(&done, state) returned -ERESTARTSYS.
Peter, is it safe to restore wait_for_completion(&done) call?
^ permalink raw reply [flat|nested] 2+ messages in thread
end of thread, other threads:[~2023-02-03 10:23 UTC | newest]
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2023-01-26 22:27 [syzbot] WARNING: locking bug in umh_complete syzbot
[not found] <20230127014137.4906-1-hdanton@sina.com>
2023-02-03 10:22 ` Tetsuo Handa
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