[syzbot] WARNING in io_cqring_overflow_flush

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 77856d911a8c Merge tag 'arm64-fixes' of git://git.kernel.o..
git tree: upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=13e722d7880000
kernel config: https://syzkaller.appspot.com/x/.config?x=334a10f27a9ee2e0
dashboard link: https://syzkaller.appspot.com/bug?extid=cf6ea1d6bb30a4ce10b2
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=112eeb13880000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=16b78bdb880000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/84863f051feb/disk-77856d91.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/87614e2a8a26/vmlinux-77856d91.xz
kernel image: https://storage.googleapis.com/syzbot-assets/cb76bad63a90/bzImage-77856d91.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+cf6ea1...@syzkaller.appspotmail.com

------------[ cut here ]------------
do not call blocking ops when !TASK_RUNNING; state=1 set at [<ffffffff81606e0e>] prepare_to_wait_exclusive+0x7e/0x2c0 kernel/sched/wait.c:290
WARNING: CPU: 1 PID: 5084 at kernel/sched/core.c:9908 __might_sleep+0x109/0x160 kernel/sched/core.c:9908
Modules linked in:
CPU: 1 PID: 5084 Comm: syz-executor102 Not tainted 6.1.0-syzkaller-13031-g77856d911a8c #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
RIP: 0010:__might_sleep+0x109/0x160 kernel/sched/core.c:9908
Code: ac 03 00 48 8d bb b8 16 00 00 48 89 fa 48 c1 ea 03 80 3c 02 00 75 34 48 8b 93 b8 16 00 00 48 c7 c7 80 d6 2b 8a e8 74 f6 5b 08 <0f> 0b e9 75 ff ff ff e8 7b 78 78 00 e9 26 ff ff ff 89 34 24 e8 8e
RSP: 0018:ffffc90003ccfbb8 EFLAGS: 00010282
RAX: 0000000000000000 RBX: ffff88802aa48000 RCX: 0000000000000000
RDX: ffff88802aa48000 RSI: ffffffff8166707c RDI: fffff52000799f69
RBP: ffffffff8a2c3500 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000080000000 R11: 0000000000000000 R12: 0000000000000244
R13: dffffc0000000000 R14: 0000000000000001 R15: 0000000000001000
FS: 00007fbcc68c0700(0000) GS:ffff8880b9b00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fbcc6964018 CR3: 0000000028bc2000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
__mutex_lock_common kernel/locking/mutex.c:580 [inline]
__mutex_lock+0x9f/0x1360 kernel/locking/mutex.c:747
io_cqring_overflow_flush io_uring/io_uring.c:674 [inline]
io_cqring_overflow_flush+0xe6/0x130 io_uring/io_uring.c:669
io_cqring_wait io_uring/io_uring.c:2534 [inline]
__do_sys_io_uring_enter+0x1590/0x21b0 io_uring/io_uring.c:3358
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7fbcc6912ec9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 81 14 00 00 90 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fbcc68c02f8 EFLAGS: 00000246 ORIG_RAX: 00000000000001aa
RAX: ffffffffffffffda RBX: 00007fbcc69974a8 RCX: 00007fbcc6912ec9
RDX: 000000000000fc0f RSI: 0000000000001000 RDI: 0000000000000003
RBP: 00007fbcc69974a0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000003 R11: 0000000000000246 R12: 00007fbcc69974ac
R13: 0000000000000003 R14: 00007fbcc68c0400 R15: 0000000000022000
</TASK>


---
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syzbot can test patches for this issue, for details see:
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[Hillf Danton]

On 20 Dec 2022 20:24:47 -0800

> syzbot found the following issue on:
>
> HEAD commit: 77856d911a8c Merge tag 'arm64-fixes' of git://git.kernel.o..
> git tree: upstream

> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=16b78bdb880000

Restore RUNNING state after wait.

#syz test https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master

--- x/io_uring/io_uring.c
+++ y/io_uring/io_uring.c
@@ -2535,10 +2535,10 @@ static int io_cqring_wait(struct io_ring
prepare_to_wait_exclusive(&ctx->cq_wait, &iowq.wq,
TASK_INTERRUPTIBLE);
ret = io_cqring_wait_schedule(ctx, &iowq, timeout);
+ finish_wait(&ctx->cq_wait, &iowq.wq);
cond_resched();
} while (ret > 0);

- finish_wait(&ctx->cq_wait, &iowq.wq);
restore_saved_sigmask_unless(ret == -EINTR);

return READ_ONCE(rings->cq.head) == READ_ONCE(rings->cq.tail) ? ret : 0;
--

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-and-tested-by: syzbot+cf6ea1...@syzkaller.appspotmail.com

Tested on:

commit: b6bb9676 Merge tag 'm68knommu-for-v6.2' of git://git.k..
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
console output: https://syzkaller.appspot.com/x/log.txt?x=1583ffbf880000
kernel config: https://syzkaller.appspot.com/x/.config?x=8ca07260bb631fb4

dashboard link: https://syzkaller.appspot.com/bug?extid=cf6ea1d6bb30a4ce10b2
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2

patch: https://syzkaller.appspot.com/x/patch.diff?x=1418e6bb880000

Note: testing is done by a robot and is best-effort only.

[Jens Axboe]

On 12/20/22 9:24 PM, syzbot wrote:
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit: 77856d911a8c Merge tag 'arm64-fixes' of git://git.kernel.o..
> git tree: upstream
> console+strace: https://syzkaller.appspot.com/x/log.txt?x=13e722d7880000
> kernel config: https://syzkaller.appspot.com/x/.config?x=334a10f27a9ee2e0
> dashboard link: https://syzkaller.appspot.com/bug?extid=cf6ea1d6bb30a4ce10b2
> compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=112eeb13880000
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=16b78bdb880000
>
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/84863f051feb/disk-77856d91.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/87614e2a8a26/vmlinux-77856d91.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/cb76bad63a90/bzImage-77856d91.xz
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+cf6ea1...@syzkaller.appspotmail.com

#syz test: git://git.kernel.dk/linux.git io_uring-6.2

--
Jens Axboe

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-and-tested-by: syzbot+cf6ea1...@syzkaller.appspotmail.com

Tested on:

commit: d1f53b3e io_uring/cancel: mark task running before re-..
git tree: git://git.kernel.dk/linux.git io_uring-6.2
console output: https://syzkaller.appspot.com/x/log.txt?x=107ab1c8480000
kernel config: https://syzkaller.appspot.com/x/.config?x=2edd87fe5cbdf43f

dashboard link: https://syzkaller.appspot.com/bug?extid=cf6ea1d6bb30a4ce10b2
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2

Note: no patches were applied.