Re: WARNING in io_disable_sqo_submit

[Pavel Begunkov <asml.silence@gmail.com>]

On 01/02/2021 15:30, syzbot wrote:
> Hello,
> 
> syzbot has tested the proposed patch but the reproducer is still triggering an issue:
> WARNING in io_uring_cancel_task_requests

#syz fix: io_uring: fix sqo ownership false positive warning

> 
> ------------[ cut here ]------------
> WARNING: CPU: 1 PID: 10843 at fs/io_uring.c:9039 io_uring_cancel_task_requests+0xe55/0x10c0 fs/io_uring.c:9039
> Modules linked in:
> CPU: 1 PID: 10843 Comm: syz-executor.3 Not tainted 5.11.0-rc5-syzkaller #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
> RIP: 0010:io_uring_cancel_task_requests+0xe55/0x10c0 fs/io_uring.c:9039
> Code: 00 00 e9 1c fe ff ff 48 8b 7c 24 18 e8 14 21 db ff e9 f2 fc ff ff 48 8b 7c 24 18 e8 05 21 db ff e9 64 f2 ff ff e8 9b a0 98 ff <0f> 0b e9 ed f2 ff ff e8 ff 20 db ff e9 c8 f5 ff ff 4c 89 ef e8 72
> RSP: 0018:ffffc9000cc37950 EFLAGS: 00010293
> RAX: 0000000000000000 RBX: ffff888027fcc000 RCX: 0000000000000000
> RDX: ffff888045a1a040 RSI: ffffffff81da2255 RDI: ffff888027fcc0d0
> RBP: ffff888027fcc0e8 R08: 0000000000000000 R09: ffff888045a1a047
> R10: ffffffff81da14cf R11: 0000000000000000 R12: ffff888027fcc000
> R13: ffff888045a1a040 R14: ffff88802e748000 R15: ffff88803ca86018
> FS:  0000000000000000(0000) GS:ffff8880b9e00000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00007f09d5e60d40 CR3: 0000000028319000 CR4: 00000000001506f0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> Call Trace:
>  io_uring_flush+0x47b/0x6e0 fs/io_uring.c:9224
>  filp_close+0xb4/0x170 fs/open.c:1286
>  close_files fs/file.c:403 [inline]
>  put_files_struct fs/file.c:418 [inline]
>  put_files_struct+0x1cc/0x350 fs/file.c:415
>  exit_files+0x7e/0xa0 fs/file.c:435
>  do_exit+0xc22/0x2ae0 kernel/exit.c:820
>  do_group_exit+0x125/0x310 kernel/exit.c:922
>  get_signal+0x427/0x20f0 kernel/signal.c:2773
>  arch_do_signal_or_restart+0x2a8/0x1eb0 arch/x86/kernel/signal.c:811
>  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:201
>  __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
>  syscall_exit_to_user_mode+0x19/0x50 kernel/entry/common.c:302
>  entry_SYSCALL_64_after_hwframe+0x44/0xa9
> RIP: 0033:0x465b09
> Code: Unable to access opcode bytes at RIP 0x465adf.
> RSP: 002b:00007f21a56f2108 EFLAGS: 00000202 ORIG_RAX: 00000000000001a9
> RAX: 0000000000000004 RBX: 000000000056c0b0 RCX: 0000000000465b09
> RDX: 00000000206d4000 RSI: 00000000200002c0 RDI: 0000000000000187
> RBP: 00000000200002c0 R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000
> R13: 00000000206d4000 R14: 0000000000000000 R15: 0000000020ee7000
> 
> 
> Tested on:
> 
> commit:         1d538571 io_uring: check kthread parked flag before sqthre..
> git tree:       git://git.kernel.dk/linux-block for-5.12/io_uring
> console output: https://syzkaller.appspot.com/x/log.txt?x=14532690d00000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=fe3e1032f57d6d25
> dashboard link: https://syzkaller.appspot.com/bug?extid=2f5d1785dc624932da78
> compiler:       
> 

-- 
Pavel Begunkov