[PATCH RESEND RESEND] io_uring: fix flush cqring overflow list while TASK_INTERRUPTIBLE

Hao Xu
2021-01-27T07:18:12Z

[ 27.073425] do not call blocking ops when !TASK_RUNNING; state=1 set at [] prepare_to_wait_exclusive+0x3a/0xc0
[ 27.075805] WARNING: CPU: 0 PID: 951 at kernel/sched/core.c:7853 __might_sleep+0x80/0xa0
[ 27.077604] Modules linked in:
[ 27.078379] CPU: 0 PID: 951 Comm: a.out Not tainted 5.11.0-rc3+ #1
[ 27.079637] Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011
[ 27.080852] RIP: 0010:__might_sleep+0x80/0xa0
[ 27.081835] Code: 65 48 8b 04 25 80 71 01 00 48 8b 90 c0 15 00 00 48 8b 70 18 48 c7 c7 08 39 95 82 c6 05 f9 5f de 08 01 48 89 d1 e8 00 c6 fa ff 0b eb bf 41 0f b6 f5 48 c7 c7 40 23 c9 82 e8 f3 48 ec 00 eb a7
[ 27.084521] RSP: 0018:ffffc90000fe3ce8 EFLAGS: 00010286
[ 27.085350] RAX: 0000000000000000 RBX: ffffffff82956083 RCX: 0000000000000000
[ 27.086348] RDX: ffff8881057a0000 RSI: ffffffff8118cc9e RDI: ffff88813bc28570
[ 27.087598] RBP: 00000000000003a7 R08: 0000000000000001 R09: 0000000000000001
[ 27.088819] R10: ffffc90000fe3e00 R11: 00000000fffef9f0 R12: 0000000000000000
[ 27.089819] R13: 0000000000000000 R14: ffff88810576eb80 R15: ffff88810576e800
[ 27.091058] FS: 00007f7b144cf740(0000) GS:ffff88813bc00000(0000) knlGS:0000000000000000
[ 27.092775] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 27.093796] CR2: 00000000022da7b8 CR3: 000000010b928002 CR4: 00000000003706f0
[ 27.094778] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 27.095780] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 27.097011] Call Trace:
[ 27.097685] __mutex_lock+0x5d/0xa30
[ 27.098565] ? prepare_to_wait_exclusive+0x71/0xc0
[ 27.099412] ? io_cqring_overflow_flush.part.101+0x6d/0x70
[ 27.100441] ? lockdep_hardirqs_on_prepare+0xe9/0x1c0
[ 27.101537] ? _raw_spin_unlock_irqrestore+0x2d/0x40
[ 27.102656] ? trace_hardirqs_on+0x46/0x110
[ 27.103459] ? io_cqring_overflow_flush.part.101+0x6d/0x70
[ 27.104317] io_cqring_overflow_flush.part.101+0x6d/0x70
[ 27.105113] io_cqring_wait+0x36e/0x4d0
[ 27.105770] ? find_held_lock+0x28/0xb0
[ 27.106370] ? io_uring_remove_task_files+0xa0/0xa0
[ 27.107076] __x64_sys_io_uring_enter+0x4fb/0x640
[ 27.107801] ? rcu_read_lock_sched_held+0x59/0xa0
[ 27.108562] ? lockdep_hardirqs_on_prepare+0xe9/0x1c0
[ 27.109684] ? syscall_enter_from_user_mode+0x26/0x70
[ 27.110731] do_syscall_64+0x2d/0x40
[ 27.111296] entry_SYSCALL_64_after_hwframe+0x44/0xa9
[ 27.112056] RIP: 0033:0x7f7b13dc8239
[ 27.112663] Code: 01 00 48 81 c4 80 00 00 00 e9 f1 fe ff ff 0f 1f 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 3d 01 f0 ff ff 73 01 c3 48 8b 0d 27 ec 2c 00 f7 d8 64 89 01 48
[ 27.115113] RSP: 002b:00007ffd6d7f5c88 EFLAGS: 00000286 ORIG_RAX: 00000000000001aa
[ 27.116562] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f7b13dc8239
[ 27.117961] RDX: 000000000000478e RSI: 0000000000000000 RDI: 0000000000000003
[ 27.118925] RBP: 00007ffd6d7f5cb0 R08: 0000000020000040 R09: 0000000000000008
[ 27.119773] R10: 0000000000000001 R11: 0000000000000286 R12: 0000000000400480
[ 27.120614] R13: 00007ffd6d7f5d90 R14: 0000000000000000 R15: 0000000000000000
[ 27.121490] irq event stamp: 5635
[ 27.121946] hardirqs last enabled at (5643): [] console_unlock+0x5c4/0x740
[ 27.123476] hardirqs last disabled at (5652): [] console_unlock+0x4e7/0x740
[ 27.125192] softirqs last enabled at (5272): [] __do_softirq+0x3c5/0x5aa
[ 27.126430] softirqs last disabled at (5267): [] asm_call_irq_on_stack+0xf/0x20
[ 27.127634] ---[ end trace 289d7e28fa60f928 ]---

This is caused by calling io_cqring_overflow_flush() which may sleep
after calling prepare_to_wait_exclusive() which set task state to
TASK_INTERRUPTIBLE

Reported-by: Abaci <abaci@linux.alibaba.com>
Fixes: 6c503150ae33 ("io_uring: patch up IOPOLL overflow_flush sync")