linux-kernel - Re: [PATCH v1 1/1] vsprintf: Fix potential unaligned access

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Message-ID: <Yd1XlN0e23GRF9i6@smile.fi.intel.com>
Date:   Tue, 11 Jan 2022 12:10:28 +0200
From:   Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To:     Sakari Ailus <sakari.ailus@...ux.intel.com>
Cc:     Petr Mladek <pmladek@...e.com>, linux-kernel@...r.kernel.org,
        Steven Rostedt <rostedt@...dmis.org>,
        Sergey Senozhatsky <senozhatsky@...omium.org>,
        Rasmus Villemoes <linux@...musvillemoes.dk>,
        Nick Desaulniers <ndesaulniers@...gle.com>
Subject: Re: [PATCH v1 1/1] vsprintf: Fix potential unaligned access

On Tue, Jan 11, 2022 at 12:12:46AM +0200, Sakari Ailus wrote:
> On Mon, Jan 10, 2022 at 10:50:49PM +0200, Andy Shevchenko wrote:
> > The %p4cc specifier in some cases might get an unaligned pointer.
> > Due to this we need to make copy to local variable once to avoid
> > potential crashes on some architectures due to improper access.
> 
> I guess this problem exists virtually everywhere where pointers are being
> handled: the pointer could be unaligned.

True. And my patch improves the situation.
See, for example, 0f70fe605fad ("hexdump: fix for non-aligned buffers").

> Does this even address the false
> positive compiler warning?

First of all, the warning is real and legit, it's not false positive.
Second, no, this is another side of the fix.

-- 
With Best Regards,
Andy Shevchenko