Re: [syzbot] WARNING in io_wq_destroy

[Jens Axboe <axboe@kernel.dk>]

On 3/22/21 11:37 AM, syzbot wrote:
> Hello,
> 
> syzbot found the following issue on:
> 
> HEAD commit:    0d02ec6b Linux 5.12-rc4
> git tree:       upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=1739e4aad00000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=5adab0bdee099d7a
> dashboard link: https://syzkaller.appspot.com/bug?extid=831debb250650baf4827
> 
> Unfortunately, I don't have any reproducer for this issue yet.
> 
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+831debb250650baf4827@syzkaller.appspotmail.com
> 
> ------------[ cut here ]------------
> WARNING: CPU: 0 PID: 15234 at fs/io-wq.c:1068 io_wq_destroy+0x1dd/0x240 fs/io-wq.c:1068
> Modules linked in:
> CPU: 1 PID: 15234 Comm: syz-executor.5 Not tainted 5.12.0-rc4-syzkaller #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
> RIP: 0010:io_wq_destroy+0x1dd/0x240 fs/io-wq.c:1068
> Code: 48 c1 ea 03 80 3c 02 00 75 6e 49 8b 3c 24 e8 2a b3 d8 ff 4c 89 e7 5b 5d 41 5c 41 5d 41 5e 41 5f e9 18 b3 d8 ff e8 73 b1 95 ff <0f> 0b e9 02 ff ff ff e8 67 b1 95 ff 48 89 ef e8 ff b2 d8 ff eb ae
> RSP: 0018:ffffc90016cb7950 EFLAGS: 00010293
> RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
> RDX: ffff88801362d4c0 RSI: ffffffff81de3cbd RDI: ffff888022177840
> RBP: ffff888022177800 R08: 000000000000003f R09: ffff8880254cb80f
> R10: ffffffff81de3b50 R11: 0000000000000000 R12: ffff8880254cb800
> R13: dffffc0000000000 R14: ffffed1004a99700 R15: 0000000000000040
> FS:  00007f51c4a75700(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 0000001b32424000 CR3: 000000002a3f7000 CR4: 00000000001506e0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> Call Trace:
>  io_wq_put fs/io-wq.c:1079 [inline]
>  io_wq_put_and_exit+0x8d/0xc0 fs/io-wq.c:1086
>  io_uring_clean_tctx+0xed/0x160 fs/io_uring.c:8890
>  __io_uring_files_cancel+0x503/0x5f0 fs/io_uring.c:8955
>  io_uring_files_cancel include/linux/io_uring.h:22 [inline]
>  do_exit+0x299/0x2a60 kernel/exit.c:780
>  do_group_exit+0x125/0x310 kernel/exit.c:922
>  get_signal+0x42c/0x2100 kernel/signal.c:2777
>  arch_do_signal_or_restart+0x2a8/0x1eb0 arch/x86/kernel/signal.c:789
>  handle_signal_work kernel/entry/common.c:147 [inline]
>  exit_to_user_mode_loop kernel/entry/common.c:171 [inline]
>  exit_to_user_mode_prepare+0x148/0x250 kernel/entry/common.c:208
>  __syscall_exit_to_user_mode_work kernel/entry/common.c:290 [inline]
>  syscall_exit_to_user_mode+0x19/0x60 kernel/entry/common.c:301
>  entry_SYSCALL_64_after_hwframe+0x44/0xae
> RIP: 0033:0x466459
> Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48
> RSP: 002b:00007f51c4a75188 EFLAGS: 00000246 ORIG_RAX: 00000000000001aa
> RAX: 0000000000000100 RBX: 000000000056bf60 RCX: 0000000000466459
> RDX: 0000000000000000 RSI: 0000000000002039 RDI: 0000000000000003
> RBP: 00000000004bf9fb R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf60
> R13: 0000000000a9fb1f R14: 00007f51c4a75300 R15: 0000000000022000

Still looking into this one, so far no luck in reproducing. But this
report is a dupe/identical of the previous one, so let's not track
both:

#syz dup: [syzbot] WARNING in io_wq_put

-- 
Jens Axboe