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

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Message-ID: <Yd2dlEMp0a8TAi9i@smile.fi.intel.com>
Date:   Tue, 11 Jan 2022 17:09:08 +0200
From:   Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To:     Petr Mladek <pmladek@...e.com>
Cc:     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>,
        Sakari Ailus <sakari.ailus@...ux.intel.com>
Subject: Re: [PATCH v1 1/1] vsprintf: Fix potential unaligned access

On Tue, Jan 11, 2022 at 03:57:36PM +0100, Petr Mladek wrote:
> On Mon 2022-01-10 22:50:49, 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.
> > 
> > Fixes: af612e43de6d ("lib/vsprintf: Add support for printing V4L2 and DRM fourccs")
> > Cc: Sakari Ailus <sakari.ailus@...ux.intel.com>
> > Signed-off-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
> 
> Looks good to me:
> 
> Reviewed-by: Petr Mladek <pmladek@...e.com>
> 
> I have already sent pull request for 5.17. Could this wait
> for 5.18 or would you prefer to get it into 5.17, please?

It's not so critical.
But would be nice to have.

> My understanding of Sakari's reply is that the current callers
> provide aligned pointers. In that case it would not be urgent.
> But I might have gotten it wrong.

Not really. There are potential unaligned callers, but Sakari
has another patch that fixes that on the (one of *) caller side.

*) I dunno how many other callers (probably none) in tree and
   how many potentially can be with similar issue.

-- 
With Best Regards,
Andy Shevchenko