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From: Dmitry Vyukov <dvyukov@google.com>
Date: Tue, 27 Dec 2016 17:38:59 +0100
Message-ID: <CACT4Y+ZxTLcpwQOBCyMZGFuXeDrbu9-RBaqzgnE57UPeDSPE+g@mail.gmail.com>
Subject: Re: x86: warning in unwind_get_return_address
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Sender: owner-linux-mm@kvack.org
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To: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Andrey Konovalov <andreyknvl@google.com>, syzkaller <syzkaller@googlegroups.com>, Andrey Ryabinin <aryabinin@virtuozzo.com>, Alexander Potapenko <glider@google.com>, kasan-dev <kasan-dev@googlegroups.com>, "linux-mm@kvack.org" <linux-mm@kvack.org>, LKML <linux-kernel@vger.kernel.org>, Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>, "x86@kernel.org" <x86@kernel.org>, Kostya Serebryany <kcc@google.com>

On Thu, Dec 22, 2016 at 6:17 AM, Josh Poimboeuf <jpoimboe@redhat.com> wrote:
> On Wed, Dec 21, 2016 at 01:46:36PM +0100, Andrey Konovalov wrote:
>> On Wed, Dec 21, 2016 at 12:36 AM, Josh Poimboeuf <jpoimboe@redhat.com> wrote:
>> >
>> > Thanks.  Looking at the stack trace, my guess is that an interrupt hit
>> > while running in generated BPF code, and the unwinder got confused
>> > because regs->ip points to the generated code.  I may need to disable
>> > that warning until we figure out a better solution.
>> >
>> > Can you share your .config file?
>>
>> Sure, attached.
>
> Ok, I was able to recreate with your config.  The culprit was generated
> code, as I suspected, though it wasn't BPF, it was a kprobe (created by
> dccpprobe_init()).
>
> I'll make a patch to disable the warning.

Hi,

I am also seeing the following warnings:

[  281.889259] WARNING: kernel stack regs at ffff8801c29a7ea8 in
syz-executor8:1302 has bad 'bp' value ffff8801c29a7f28
[  833.994878] WARNING: kernel stack regs at ffff8801c4e77ea8 in
syz-executor1:13094 has bad 'bp' value ffff8801c4e77f28

Can it also be caused by bpf/kprobe?

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