[syzbot] WARNING: still has locks held in io_sq_thread

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 81b1d39f Merge tag '5.12-rc4-smb3' of git://git.samba.org/..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=10fcce62d00000
kernel config: https://syzkaller.appspot.com/x/.config?x=d4e9addca54f3b44
dashboard link: https://syzkaller.appspot.com/bug?extid=796d767eb376810256f5
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=17d06ddcd00000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=150764bed00000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+796d76...@syzkaller.appspotmail.com

====================================
WARNING: iou-sqp-8386/8387 still has locks held!
5.12.0-rc4-syzkaller #0 Not tainted
------------------------------------
1 lock held by iou-sqp-8386/8387:
#0: ffff88801e1d2470 (&sqd->lock){+.+.}-{3:3}, at: io_sq_thread+0x24c/0x13a0 fs/io_uring.c:6731

stack backtrace:
CPU: 1 PID: 8387 Comm: iou-sqp-8386 Not tainted 5.12.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:79 [inline]
dump_stack+0x141/0x1d7 lib/dump_stack.c:120
try_to_freeze include/linux/freezer.h:66 [inline]
get_signal+0x171a/0x2150 kernel/signal.c:2576
io_sq_thread+0x8d2/0x13a0 fs/io_uring.c:6748


---
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[Jens Axboe]

On 3/29/21 1:34 AM, syzbot wrote:
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit: 81b1d39f Merge tag '5.12-rc4-smb3' of git://git.samba.org/..
> git tree: upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=10fcce62d00000
> kernel config: https://syzkaller.appspot.com/x/.config?x=d4e9addca54f3b44
> dashboard link: https://syzkaller.appspot.com/bug?extid=796d767eb376810256f5
> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=17d06ddcd00000
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=150764bed00000

#syz test: git://git.kernel.dk/linux-block io_uring-5.12

--
Jens Axboe

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
WARNING in kvm_wait

------------[ cut here ]------------
raw_local_irq_restore() called with IRQs enabled
WARNING: CPU: 1 PID: 5134 at kernel/locking/irqflag-debug.c:10 warn_bogus_irq_restore+0x1d/0x20 kernel/locking/irqflag-debug.c:10
Modules linked in:
CPU: 1 PID: 5134 Comm: syz-executor.2 Not tainted 5.12.0-rc2-syzkaller #0

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011

RIP: 0010:warn_bogus_irq_restore+0x1d/0x20 kernel/locking/irqflag-debug.c:10
Code: bf ff cc cc cc cc cc cc cc cc cc cc cc 80 3d 65 c2 0f 04 00 74 01 c3 48 c7 c7 a0 7b 6b 89 c6 05 54 c2 0f 04 01 e8 65 19 bf ff <0f> 0b c3 48 39 77 10 0f 84 97 00 00 00 66 f7 47 22 f0 ff 74 4b 48
RSP: 0018:ffffc90002f5f9c0 EFLAGS: 00010286
RAX: 0000000000000000 RBX: ffff888023a7d040 RCX: 0000000000000000
RDX: ffff88801bbcc2c0 RSI: ffffffff815b7375 RDI: fffff520005ebf2a
RBP: 0000000000000200 R08: 0000000000000000 R09: 0000000000000000
R10: ffffffff815b00de R11: 0000000000000000 R12: 0000000000000003
R13: ffffed100474fa08 R14: 0000000000000001 R15: ffff8880b9f36000
FS: 000000000293e400(0000) GS:ffff8880b9f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffd20e04f88 CR3: 00000000116b8000 CR4: 00000000001506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
kvm_wait arch/x86/kernel/kvm.c:860 [inline]
kvm_wait+0xc9/0xe0 arch/x86/kernel/kvm.c:837
pv_wait arch/x86/include/asm/paravirt.h:564 [inline]
pv_wait_head_or_lock kernel/locking/qspinlock_paravirt.h:470 [inline]
__pv_queued_spin_lock_slowpath+0x8b8/0xb40 kernel/locking/qspinlock.c:508
pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:554 [inline]
queued_spin_lock_slowpath arch/x86/include/asm/qspinlock.h:51 [inline]
queued_spin_lock include/asm-generic/qspinlock.h:85 [inline]
do_raw_spin_lock+0x200/0x2b0 kernel/locking/spinlock_debug.c:113
spin_lock include/linux/spinlock.h:354 [inline]
ext4_lock_group fs/ext4/ext4.h:3383 [inline]
__ext4_new_inode+0x384f/0x5570 fs/ext4/ialloc.c:1188
ext4_symlink+0x489/0xd50 fs/ext4/namei.c:3347
vfs_symlink fs/namei.c:4176 [inline]
vfs_symlink+0x10f/0x270 fs/namei.c:4161
do_symlinkat+0x27a/0x300 fs/namei.c:4206
do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x465d67
Code: 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 58 00 00 00 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:00007ffc15a180e8 EFLAGS: 00000206 ORIG_RAX: 0000000000000058
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000465d67
RDX: 00007ffc15a181d3 RSI: 00000000004bfab2 RDI: 00007ffc15a181c0
RBP: 0000000000000000 R08: 0000000000000000 R09: 00007ffc15a17f80
R10: 00007ffc15a17e37 R11: 0000000000000206 R12: 0000000000000001
R13: 0000000000000000 R14: 0000000000000001 R15: 00007ffc15a181c0


Tested on:

commit: d80a59fb io_uring: drop sqd lock before handling signals f..
git tree: git://git.kernel.dk/linux-block io_uring-5.12
console output: https://syzkaller.appspot.com/x/log.txt?x=14a9b21ad00000
kernel config: https://syzkaller.appspot.com/x/.config?x=473f8fc78a7207b4
dashboard link: https://syzkaller.appspot.com/bug?extid=796d767eb376810256f5
compiler:

[Jens Axboe]

Same one that keeps happening, it's not related.

--
Jens Axboe

[syzbot]

syzbot has bisected this issue to:

commit c8cc7e853192d520ab6a5957f5081034103587ae
Author: Peter Zijlstra <pet...@infradead.org>
Date: Tue Feb 9 08:30:03 2021 +0000

lockdep: Noinstr annotate warn_bogus_irq_restore()

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=152deb3ad00000
start commit: 81b1d39f Merge tag '5.12-rc4-smb3' of git://git.samba.org/..
git tree: upstream
final oops: https://syzkaller.appspot.com/x/report.txt?x=172deb3ad00000
console output: https://syzkaller.appspot.com/x/log.txt?x=132deb3ad00000

kernel config: https://syzkaller.appspot.com/x/.config?x=d4e9addca54f3b44
dashboard link: https://syzkaller.appspot.com/bug?extid=796d767eb376810256f5
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=17d06ddcd00000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=150764bed00000

Reported-by: syzbot+796d76...@syzkaller.appspotmail.com
Fixes: c8cc7e853192 ("lockdep: Noinstr annotate warn_bogus_irq_restore()")

For information about bisection process see: https://goo.gl/tpsmEJ#bisection