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Date:   Sun, 2 Jul 2023 20:20:41 -0700
From:   Kees Cook <keescook@chromium.org>
To:     Bagas Sanjaya <bagasdotme@gmail.com>
Cc:     Mirsad Goran Todorovac <mirsad.todorovac@alu.unizg.hr>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Linux LLVM <llvm@lists.linux.dev>,
        linux-kbuild@vger.kernel.org,
        Linux Regressions <regressions@list.linux.dev>,
        Nathan Chancellor <nathan@kernel.org>,
        Nick Desaulniers <ndesaulniers@google.com>,
        Guenter Roeck <linux@roeck-us.net>
Subject: Re: [CRASH][BISECTED] 6.4.1 crash in boot
Message-ID: <202307022018.B26F5795@keescook>
References: <9a8e34ad-8a8b-3830-4878-3c2c82e69dd9@alu.unizg.hr>
 <ZKIoBVzrjZ+Ybxy9@debian.me>
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On Mon, Jul 03, 2023 at 08:44:37AM +0700, Bagas Sanjaya wrote:
> On Sun, Jul 02, 2023 at 06:36:12PM +0200, Mirsad Goran Todorovac wrote:
> > Hi,
> > 
> > After new git pull the kernel in Torvalds tree with default debug config
> > failed to boot with error that occurs prior to mounting filesystems, so there
> > is no log safe for the screenshot(s) here:
> > 
> > [1] https://domac.alu.unizg.hr/~mtodorov/linux/crashes/2023-07-02/
> > 
> > Bisect shows the first bad commit is 2d47c6956ab3 (v6.4-rc2-1-g2d47c6956ab3):
> > 
> > # good: [98be618ad03010b1173fc3c35f6cbb4447ee2b07] Merge tag 'Smack-for-6.5' of https://github.com/cschaufler/smack-next
> > git bisect good 98be618ad03010b1173fc3c35f6cbb4447ee2b07
> > # bad: [f4a0659f823e5a828ea2f45b4849ea8e2dd2984c] drm/i2c: tda998x: Replace all non-returning strlcpy with strscpy
> > git bisect bad f4a0659f823e5a828ea2f45b4849ea8e2dd2984c
> > .
> > .
> > .
> > # bad: [2d47c6956ab3c8b580a59d7704aab3e2a4882b6c] ubsan: Tighten UBSAN_BOUNDS on GCC
> > git bisect bad 2d47c6956ab3c8b580a59d7704aab3e2a4882b6c
> > # first bad commit: [2d47c6956ab3c8b580a59d7704aab3e2a4882b6c] ubsan: Tighten UBSAN_BOUNDS on GCC
> > 
> > The architecture is Ubuntu 22.04 with lshw and config give in the attachment.
> 
> Can you show early kernel log (something like dmesg)?
> 
> Anyway, I'm adding it to regzbot:
> 
> #regzbot ^introduced: 2d47c6956ab3c8
> #regzbot title: Linux kernel fails to boot due to UBSAN_BOUNDS tightening

I'm confused. Commit 2d47c6956ab3c8b580a59d7704aab3e2a4882b6c isn't in the v6.4
tree... it's only in Linus's ToT.

Also, the config you included does not show CONFIG_UBSAN_BOUNDS_STRICT
as even being available, much less present. Something seems very wrong
with this report...

-Kees

-- 
Kees Cook