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Date:   Tue, 10 Aug 2021 16:31:33 +0300
From:   Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To:     Chris von Recklinghausen <crecklin@redhat.com>
Cc:     pmladek@suse.com, rostedt@goodmis.org, senozhatsky@chromium.org,
        linux@rasmusvillemoes.dk, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] fix UBSAN splat in test_scanf
Message-ID: <YRJ/tTuj7r4jppv4@smile.fi.intel.com>
References: <20210809102013.525671-1-crecklin@redhat.com>
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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
?

> 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.

-- 
With Best Regards,
Andy Shevchenko