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Subject: Re: [PATCH] fix UBSAN splat in test_scanf
To:     Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc:     pmladek@suse.com, rostedt@goodmis.org, senozhatsky@chromium.org,
        linux@rasmusvillemoes.dk, linux-kernel@vger.kernel.org
References: <20210809102013.525671-1-crecklin@redhat.com>
 <YRJ/tTuj7r4jppv4@smile.fi.intel.com>
From:   Christoph von Recklinghausen <crecklin@redhat.com>
Message-ID: <1f4aa937-8e5d-33db-6479-e9b2011be147@redhat.com>
Date:   Tue, 10 Aug 2021 09:37:01 -0400
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On 8/10/21 9:31 AM, Andy Shevchenko wrote:
> On Mon, Aug 09, 2021 at 06:20:13AM -0400, Chris von Recklinghausen wrote:
>
> Thanks for the report and fix!
>
> First of all, have you seen this:
> https://lore.kernel.org/lkml/20210727150132.28920-1-andriy.shevchenko@linux.intel.com/T/#u
> ?


No I hadn't seen it. I'll defer to this fix then.

Thanks,

Chris


>
>> On a system with CONFIG_UBSAN_SHIFT=y, the following splat was observed:
>> [  104.676826] test_scanf: loaded.
>> [  104.680862] ================================================================================
>> [  104.690304] UBSAN: shift-out-of-bounds in lib/test_scanf.c:274:51
>> [  104.697144] shift exponent 32 is too large for 32-bit type 'unsigned int'
> As you may see in the above the rule of thumb is to include only meaningful
> parts of the oops.
>