general protection fault in finish_writeback_work

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: 24ccb0ab qede: qede_fp: simplify a bit 'qede_rx_build_skb()'
git tree: net
console output: https://syzkaller.appspot.com/x/log.txt?x=11a5b229600000
kernel config: https://syzkaller.appspot.com/x/.config?x=dfcf592db22b9132
dashboard link: https://syzkaller.appspot.com/bug?extid=828abc56e48ada4b0195
compiler: gcc (GCC) 9.0.0 20181231 (experimental)

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+828abc...@syzkaller.appspotmail.com

kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 8777 Comm: kworker/u4:5 Not tainted 5.3.0+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Workqueue: writeback wb_workfn (flush-8:0)
RIP: 0010:__lock_acquire+0x1265/0x4e70 kernel/locking/lockdep.c:3828
Code: 00 0f 85 0e 26 00 00 48 81 c4 e8 00 00 00 5b 41 5c 41 5d 41 5e 41 5f
5d c3 48 b8 00 00 00 00 00 fc ff df 4c 89 f2 48 c1 ea 03 <80> 3c 02 00 0f
85 dd 2a 00 00 49 81 3e a0 25 06 8a 0f 84 4e ee ff
RSP: 0018:ffff88806930f938 EFLAGS: 00010007
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 03fffe22022b47e2 RSI: 0000000000000000 RDI: 0000000000000001
RBP: ffff88806930fa48 R08: 0000000000000001 R09: 0000000000000001
R10: fffffbfff138cf90 R11: ffff8880693002c0 R12: 1ffff110115a3f15
R13: 0000000000000000 R14: 1ffff110115a3f15 R15: 0000000000000001
FS: 0000000000000000(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f2136820ea0 CR3: 000000008ab86000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4487
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0x95/0xcd kernel/locking/spinlock.c:159
__wake_up_common_lock+0xc8/0x150 kernel/sched/wait.c:122
__wake_up+0xe/0x10 kernel/sched/wait.c:142
finish_writeback_work.isra.0+0xf6/0x120 fs/fs-writeback.c:168
wb_do_writeback fs/fs-writeback.c:2030 [inline]
wb_workfn+0x34f/0x11e0 fs/fs-writeback.c:2070
process_one_work+0x9af/0x1740 kernel/workqueue.c:2269
worker_thread+0x98/0xe40 kernel/workqueue.c:2415
kthread+0x361/0x430 kernel/kthread.c:255
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352
Modules linked in:
---[ end trace b7a1091622454beb ]---
RIP: 0010:__lock_acquire+0x1265/0x4e70 kernel/locking/lockdep.c:3828
Code: 00 0f 85 0e 26 00 00 48 81 c4 e8 00 00 00 5b 41 5c 41 5d 41 5e 41 5f
5d c3 48 b8 00 00 00 00 00 fc ff df 4c 89 f2 48 c1 ea 03 <80> 3c 02 00 0f
85 dd 2a 00 00 49 81 3e a0 25 06 8a 0f 84 4e ee ff
RSP: 0018:ffff88806930f938 EFLAGS: 00010007
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 03fffe22022b47e2 RSI: 0000000000000000 RDI: 0000000000000001
RBP: ffff88806930fa48 R08: 0000000000000001 R09: 0000000000000001
R10: fffffbfff138cf90 R11: ffff8880693002c0 R12: 1ffff110115a3f15
R13: 0000000000000000 R14: 1ffff110115a3f15 R15: 0000000000000001
FS: 0000000000000000(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f2136820ea0 CR3: 000000008ab86000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


---
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:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

[Eric Biggers]

This was probably fixed by commit 8e00c4e9dd85:

#syz fix: writeback: fix use-after-free in finish_writeback_work()