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Sender: Guenter Roeck <groeck7@gmail.com>
Message-ID: <4fa56264-f188-46f9-cc77-117b469b3328@roeck-us.net>
Date:   Sun, 2 Jul 2023 20:58:55 -0700
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Subject: Re: [CRASH][BISECTED] 6.4.1 crash in boot
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From:   Guenter Roeck <linux@roeck-us.net>
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>
 <625e951e-9922-d15d-5520-e8cd5eba1995@roeck-us.net>
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On 7/2/23 20:26, Guenter Roeck wrote:
> 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.
> 

Ah, sorry, I didn't realize that the subject claims that the problem
would be in 6.4.1. That indeed does not match the bisect results.

Guenter

> 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
>>
>