[syzbot] upstream boot error: WARNING in kvm_wait

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 280d542f Merge tag 'drm-fixes-2021-03-05' of git://anongit..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=138c7a92d00000
kernel config: https://syzkaller.appspot.com/x/.config?x=dc4003509ab3fc78
dashboard link: https://syzkaller.appspot.com/bug?extid=a4c8bc1d1dc7b620630d

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+a4c8bc...@syzkaller.appspotmail.com

------------[ cut here ]------------
raw_local_irq_restore() called with IRQs enabled
WARNING: CPU: 2 PID: 213 at kernel/locking/irqflag-debug.c:10 warn_bogus_irq_restore+0x1d/0x20 kernel/locking/irqflag-debug.c:10
Modules linked in:
CPU: 2 PID: 213 Comm: kworker/u17:4 Not tainted 5.12.0-rc1-syzkaller #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-2 04/01/2014
Workqueue: events_unbound call_usermodehelper_exec_work

RIP: 0010:warn_bogus_irq_restore+0x1d/0x20 kernel/locking/irqflag-debug.c:10
Code: be ff cc cc cc cc cc cc cc cc cc cc cc 80 3d e4 38 af 04 00 74 01 c3 48 c7 c7 a0 8f 6b 89 c6 05 d3 38 af 04 01 e8 e7 b9 be ff <0f> 0b c3 48 39 77 10 0f 84 97 00 00 00 66 f7 47 22 f0 ff 74 4b 48
RSP: 0000:ffffc90000fe7770 EFLAGS: 00010286

RAX: 0000000000000000 RBX: ffffffff8c0e9c68 RCX: 0000000000000000
RDX: ffff8880116bc3c0 RSI: ffffffff815c0cf5 RDI: fffff520001fcee0
RBP: 0000000000000200 R08: 0000000000000000 R09: 0000000000000001
R10: ffffffff815b9a5e R11: 0000000000000000 R12: 0000000000000003
R13: fffffbfff181d38d R14: 0000000000000001 R15: ffff88802cc36000
FS: 0000000000000000(0000) GS:ffff88802cc00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000000bc8e000 CR4: 0000000000150ee0
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]
copy_fs_struct+0x1c8/0x340 fs/fs_struct.c:123
copy_fs kernel/fork.c:1443 [inline]
copy_process+0x4dc2/0x6fd0 kernel/fork.c:2088
kernel_clone+0xe7/0xab0 kernel/fork.c:2462
kernel_thread+0xb5/0xf0 kernel/fork.c:2514
call_usermodehelper_exec_work kernel/umh.c:172 [inline]
call_usermodehelper_exec_work+0xcc/0x180 kernel/umh.c:158
process_one_work+0x98d/0x1600 kernel/workqueue.c:2275
worker_thread+0x64c/0x1120 kernel/workqueue.c:2421
kthread+0x3b1/0x4a0 kernel/kthread.c:292
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294


---
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[Dmitry Vyukov]

On Fri, Mar 5, 2021 at 9:56 PM syzbot
<syzbot+a4c8bc...@syzkaller.appspotmail.com> wrote:
>
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit: 280d542f Merge tag 'drm-fixes-2021-03-05' of git://anongit..
> git tree: upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=138c7a92d00000
> kernel config: https://syzkaller.appspot.com/x/.config?x=dc4003509ab3fc78
> dashboard link: https://syzkaller.appspot.com/bug?extid=a4c8bc1d1dc7b620630d
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+a4c8bc...@syzkaller.appspotmail.com

+Mark, I've enabled CONFIG_DEBUG_IRQFLAGS on syzbot and it led to this breakage.
Is it a bug in kvm_wait or in the debugging code itself? If it's a
real bug, I would assume it's pretty bad as it happens all the time.

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[Dmitry Vyukov]

On Sat, Mar 6, 2021 at 12:37 PM Dmitry Vyukov <dvy...@google.com> wrote:
>
> On Fri, Mar 5, 2021 at 9:56 PM syzbot
> <syzbot+a4c8bc...@syzkaller.appspotmail.com> wrote:
> >
> > Hello,
> >
> > syzbot found the following issue on:
> >
> > HEAD commit: 280d542f Merge tag 'drm-fixes-2021-03-05' of git://anongit..
> > git tree: upstream
> > console output: https://syzkaller.appspot.com/x/log.txt?x=138c7a92d00000
> > kernel config: https://syzkaller.appspot.com/x/.config?x=dc4003509ab3fc78
> > dashboard link: https://syzkaller.appspot.com/bug?extid=a4c8bc1d1dc7b620630d
> >
> > IMPORTANT: if you fix the issue, please add the following tag to the commit:
> > Reported-by: syzbot+a4c8bc...@syzkaller.appspotmail.com
>
> +Mark, I've enabled CONFIG_DEBUG_IRQFLAGS on syzbot and it led to this breakage.
> Is it a bug in kvm_wait or in the debugging code itself? If it's a
> real bug, I would assume it's pretty bad as it happens all the time.

Wanpeng posted a fix for this:

https://lore.kernel.org/kvm/1614057902-23774-1-gi...@tencent.com/

#syz fix: x86/kvm: Fix broken irq restoration in kvm_wait