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Date:   Wed, 3 Feb 2021 17:27:35 -0600
From:   Josh Poimboeuf <jpoimboe@redhat.com>
To:     Ivan Babrou <ivan@cloudflare.com>
Cc:     Peter Zijlstra <peterz@infradead.org>,
        kernel-team <kernel-team@cloudflare.com>,
        Ignat Korchagin <ignat@cloudflare.com>,
        Hailong liu <liu.hailong6@zte.com.cn>,
        Andrey Ryabinin <aryabinin@virtuozzo.com>,
        Alexander Potapenko <glider@google.com>,
        Dmitry Vyukov <dvyukov@google.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
        Miroslav Benes <mbenes@suse.cz>,
        Julien Thierry <jthierry@redhat.com>,
        Jiri Slaby <jirislaby@kernel.org>, kasan-dev@googlegroups.com,
        linux-mm@kvack.org, linux-kernel <linux-kernel@vger.kernel.org>,
        Alasdair Kergon <agk@redhat.com>,
        Mike Snitzer <snitzer@redhat.com>, dm-devel@redhat.com,
        "Steven Rostedt (VMware)" <rostedt@goodmis.org>,
        Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Martin KaFai Lau <kafai@fb.com>,
        Song Liu <songliubraving@fb.com>, Yonghong Song <yhs@fb.com>,
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        Linux Kernel Network Developers <netdev@vger.kernel.org>,
        bpf@vger.kernel.org, Alexey Kardashevskiy <aik@ozlabs.ru>
Subject: Re: BUG: KASAN: stack-out-of-bounds in
 unwind_next_frame+0x1df5/0x2650
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On Wed, Feb 03, 2021 at 02:41:53PM -0800, Ivan Babrou wrote:
> On Wed, Feb 3, 2021 at 11:05 AM Josh Poimboeuf <jpoimboe@redhat.com> wrote:
> >
> > On Wed, Feb 03, 2021 at 09:46:55AM -0800, Ivan Babrou wrote:
> > > > Can you pretty please not line-wrap console output? It's unreadable.
> > >
> > > GMail doesn't make it easy, I'll send a link to a pastebin next time.
> > > Let me know if you'd like me to regenerate the decoded stack.
> > >
> > > > > edfd9b7838ba5e47f19ad8466d0565aba5c59bf0 is the first bad commit
> > > > > commit edfd9b7838ba5e47f19ad8466d0565aba5c59bf0
> > > >
> > > > Not sure what tree you're on, but that's not the upstream commit.
> > >
> > > I mentioned that it's a rebased core-static_call-2020-10-12 tag and
> > > added a link to the upstream hash right below.
> > >
> > > > > Author: Steven Rostedt (VMware) <rostedt@goodmis.org>
> > > > > Date:   Tue Aug 18 15:57:52 2020 +0200
> > > > >
> > > > >     tracepoint: Optimize using static_call()
> > > > >
> > > >
> > > > There's a known issue with that patch, can you try:
> > > >
> > > >   http://lkml.kernel.org/r/20210202220121.435051654@goodmis.org
> > >
> > > I've tried it on top of core-static_call-2020-10-12 tag rebased on top
> > > of v5.9 (to make it reproducible), and the patch did not help. Do I
> > > need to apply the whole series or something else?
> >
> > Can you recreate with this patch, and add "unwind_debug" to the cmdline?
> > It will spit out a bunch of stack data.
> 
> Here's the three I'm building:
> 
> * https://github.com/bobrik/linux/tree/ivan/static-call-5.9
> 
> It contains:
> 
> * v5.9 tag as the base
> * static_call-2020-10-12 tag
> * dm-crypt patches to reproduce the issue with KASAN
> * x86/unwind: Add 'unwind_debug' cmdline option
> * tracepoint: Fix race between tracing and removing tracepoint
> 
> The very same issue can be reproduced on 5.10.11 with no patches,
> but I'm going with 5.9, since it boils down to static call changes.
> 
> Here's the decoded stack from the kernel with unwind debug enabled:
> 
> * https://gist.github.com/bobrik/ed052ac0ae44c880f3170299ad4af56b
> 
> See my first email for the exact commands that trigger this.

Thanks.  Do you happen to have the original dmesg, before running it
through the post-processing script?


I assume you're using decode_stacktrace.sh?  It could use some
improvement, it's stripping the function offset.

Also spaces are getting inserted in odd places, messing the alignment.

[  137.291837][    C0] ffff88809c409858: d7c4f3ce817a1700 (0xd7c4f3ce817a1700)
[  137.291837][    C0] ffff88809c409860: 0000000000000000 (0x0)
[  137.291839][    C0] ffff88809c409868: 00000000ffffffff (0xffffffff)
[ 137.291841][ C0] ffff88809c409870: ffffffffa4f01a52 unwind_next_frame (arch/x86/kernel/unwind_orc.c:380 arch/x86/kernel/unwind_orc.c:553)
[ 137.291843][ C0] ffff88809c409878: ffffffffa4f01a52 unwind_next_frame (arch/x86/kernel/unwind_orc.c:380 arch/x86/kernel/unwind_orc.c:553)
[  137.291844][    C0] ffff88809c409880: ffff88809c409ac8 (0xffff88809c409ac8)
[  137.291845][    C0] ffff88809c409888: 0000000000000086 (0x86)

-- 
Josh