From: Sean Christopherson <seanjc@google.com>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: syzbot <syzbot+a3fcd59df1b372066f5a@syzkaller.appspotmail.com>,
akpm@linux-foundation.org, bp@alien8.de, hpa@zytor.com,
jmattson@google.com, joro@8bytes.org, kvm@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
mark.rutland@arm.com, masahiroy@kernel.org, mingo@redhat.com,
pbonzini@redhat.com, peterz@infradead.org,
rafael.j.wysocki@intel.com, rostedt@goodmis.org,
sedat.dilek@gmail.com, syzkaller-bugs@googlegroups.com,
vitor@massaru.org, vkuznets@redhat.com, wanpengli@tencent.com,
will@kernel.org, x86@kernel.org
Subject: Re: [syzbot] general protection fault in try_grab_compound_head
Date: Mon, 12 Jul 2021 21:29:00 +0000 [thread overview]
Message-ID: <YOy0HAnhsXJ4W210@google.com> (raw)
In-Reply-To: <87fswpot3i.ffs@nanos.tec.linutronix.de>
On Thu, Jul 08, 2021, Thomas Gleixner wrote:
> On Sat, Jul 03 2021 at 13:24, syzbot wrote:
> > syzbot has bisected this issue to:
> >
> > commit 997acaf6b4b59c6a9c259740312a69ea549cc684
> > Author: Mark Rutland <mark.rutland@arm.com>
> > Date: Mon Jan 11 15:37:07 2021 +0000
> >
> > lockdep: report broken irq restoration
>
> That's the commit which makes the underlying problem visible:
>
> raw_local_irq_restore() called with IRQs enabled
>
> and is triggered by this call chain:
>
> kvm_wait arch/x86/kernel/kvm.c:860 [inline]
> kvm_wait+0xc3/0xe0 arch/x86/kernel/kvm.c:837
And the bug in kvm_wait() was fixed by commit f4e61f0c9add ("x86/kvm: Fix broken
irq restoration in kvm_wait"). The bisection is bad, syzbot happened into the
kvm_wait() WARN and got distracted. The original #GP looks stable, if someone
from mm land has bandwidth.
next prev parent reply other threads:[~2021-07-12 21:29 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-03 15:41 syzbot
2021-07-03 20:24 ` syzbot
2021-07-08 13:03 ` Thomas Gleixner
2021-07-12 21:29 ` Sean Christopherson [this message]
2021-07-13 1:08 ` Joao Martins
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