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Sender: Guenter Roeck <groeck7@gmail.com>
Message-ID: <625e951e-9922-d15d-5520-e8cd5eba1995@roeck-us.net>
Date:   Sun, 2 Jul 2023 20:26:20 -0700
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Subject: Re: [CRASH][BISECTED] 6.4.1 crash in boot
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To:     Kees Cook <keescook@chromium.org>,
        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>
References: <9a8e34ad-8a8b-3830-4878-3c2c82e69dd9@alu.unizg.hr>
 <ZKIoBVzrjZ+Ybxy9@debian.me> <202307022018.B26F5795@keescook>
From:   Guenter Roeck <linux@roeck-us.net>
In-Reply-To: <202307022018.B26F5795@keescook>
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On 7/2/23 20:20, Kees Cook wrote:
> 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.
> 

In ToT:

$ git describe 2d47c6956ab3
v6.4-rc2-1-g2d47c6956ab3

$ git describe --contains 2d47c6956ab3
next-20230616~2^2~51
$ git describe --contains --match 'v*' 2d47c6956ab3
fatal: cannot describe '2d47c6956ab3c8b580a59d7704aab3e2a4882b6c'

"git describe" always shows the parent tree, which I guess was based on
v6.4-rc2.

Guenter


> 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
>