Re: [PATCH] fix UBSAN splat in test_scanf

[Andy Shevchenko]

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@xxxxxxxxxxxxxxx/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