general protection fault in perf_trace_lock

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: 0b5b1f9a78b5 Merge tag 'for-linus' of git://git.kernel.org..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=15e96030400000
kernel config: https://syzkaller.appspot.com/x/.config?x=2dc0cd7c2eefb46f
dashboard link: https://syzkaller.appspot.com/bug?extid=c7e302dec907a7632567
compiler: gcc (GCC) 8.0.1 20180413 (experimental)
CC: [da...@davemloft.net eri...@gmail.com
linux-...@vger.kernel.org lu...@ionkov.net net...@vger.kernel.org
rmin...@sandia.gov v9fs-de...@lists.sourceforge.net]

Unfortunately, I don't have any reproducer for this crash yet.

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+c7e302...@syzkaller.appspotmail.com

binder: 21725:21730 IncRefs 0 refcount change on invalid ref 0 ret -22
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: 26 Comm: kworker/0:2 Not tainted 4.18.0-rc7+ #176
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Workqueue: events p9_poll_workfn
RIP: 0010:perf_trace_lock+0xbb/0x920 include/trace/events/lock.h:39
Code: 20 f2 f2 f2 f2 c7 40 24 00 f2 f2 f2 65 48 8b 04 25 28 00 00 00 48 89
45 d0 31 c0 48 8d 46 18 48 89 85 70 fe ff ff 48 c1 e8 03 <80> 3c 10 00 0f
85 3a 05 00 00 49 8b 78 18 48 85 ff 0f 84 23 04 00
binder: 21725:21756 BC_ACQUIRE_DONE u0000000000000000 no match
RSP: 0018:ffff8801d9847008 EFLAGS: 00010006
RAX: 0000000000000006 RBX: 1ffff1003b308e09 RCX: ffffffff867e85e5
RDX: dffffc0000000000 RSI: 0000000000000018 RDI: ffffffff87f7b700
RBP: ffff8801d98471d0 R08: 0000000000000018 R09: ffffed00332291b0
R10: ffffed00332291b0 R11: ffff880199148d83 R12: ffff8801d98471a8
R13: 0000000000000018 R14: dffffc0000000000 R15: ffffffff87f7b700
FS: 0000000000000000(0000) GS:ffff8801db000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f0b2981bdb8 CR3: 000000019c56e000 CR4: 00000000001406f0
DR0: 0000000020000000 DR1: 0000000020000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
Call Trace:
trace_lock_release include/trace/events/lock.h:58 [inline]
lock_release+0x5fa/0xa30 kernel/locking/lockdep.c:3942
__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:158 [inline]
_raw_spin_unlock_irqrestore+0x1f/0xc0 kernel/locking/spinlock.c:184
spin_unlock_irqrestore include/linux/spinlock.h:365 [inline]
p9_conn_cancel+0x9b6/0xd30 net/9p/trans_fd.c:208
p9_poll_mux net/9p/trans_fd.c:620 [inline]
p9_poll_workfn+0x4b2/0x6d0 net/9p/trans_fd.c:1107
process_one_work+0xc73/0x1ba0 kernel/workqueue.c:2153
worker_thread+0x189/0x13c0 kernel/workqueue.c:2296
kthread+0x345/0x410 kernel/kthread.c:246
ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:412
Modules linked in:
Dumping ftrace buffer:
(ftrace buffer empty)
---[ end trace a22d9bc3f66cafcb ]---
RIP: 0010:perf_trace_lock+0xbb/0x920 include/trace/events/lock.h:39
Code: 20 f2 f2 f2 f2 c7 40 24 00 f2 f2 f2 65 48 8b 04 25 28 00 00 00 48 89
45 d0 31 c0 48 8d 46 18 48 89 85 70 fe ff ff 48 c1 e8 03 <80> 3c 10 00 0f
85 3a 05 00 00 49 8b 78 18 48 85 ff 0f 84 23 04 00
RSP: 0018:ffff8801d9847008 EFLAGS: 00010006
RAX: 0000000000000006 RBX: 1ffff1003b308e09 RCX: ffffffff867e85e5
RDX: dffffc0000000000 RSI: 0000000000000018 RDI: ffffffff87f7b700
RBP: ffff8801d98471d0 R08: 0000000000000018 R09: ffffed00332291b0
R10: ffffed00332291b0 R11: ffff880199148d83 R12: ffff8801d98471a8
R13: 0000000000000018 R14: dffffc0000000000 R15: ffffffff87f7b700
FS: 0000000000000000(0000) GS:ffff8801db000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f0b2981bdb8 CR3: 000000019c56e000 CR4: 00000000001406f0
DR0: 0000000020000000 DR1: 0000000020000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600


---
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[Dmitry Vyukov]

The same as "general protection fault in p9_conn_cancel" with
misattributed frame. The misattributed frame is fixed now.

#syz invalid

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