linux-kernel - Re: [PATCH] mm: ensure alloc_flags in slow path are initialized

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <alpine.DEB.2.10.1701231454170.126378@chino.kir.corp.google.com>
Date:   Mon, 23 Jan 2017 14:54:28 -0800 (PST)
From:   David Rientjes <rientjes@...gle.com>
To:     Arnd Bergmann <arnd@...db.de>
cc:     Andrew Morton <akpm@...ux-foundation.org>,
        Vlastimil Babka <vbabka@...e.cz>,
        Mel Gorman <mgorman@...hsingularity.net>,
        Michal Hocko <mhocko@...e.com>,
        Johannes Weiner <hannes@...xchg.org>,
        Joonsoo Kim <iamjoonsoo.kim@....com>, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] mm: ensure alloc_flags in slow path are initialized

On Mon, 23 Jan 2017, Arnd Bergmann wrote:

> The __alloc_pages_slowpath() has gotten rather complex and gcc
> is no longer able to follow the gotos and prove that the
> alloc_flags variable is initialized at the time it is used:
> 
> mm/page_alloc.c: In function '__alloc_pages_slowpath':
> mm/page_alloc.c:3565:15: error: 'alloc_flags' may be used uninitialized in this function [-Werror=maybe-uninitialized]
> 
> To be honest, I can't figure that out either, maybe it is or
> maybe not, but moving the existing initialization up a little
> higher looks safe and makes it obvious to both me and gcc that
> the initialization comes before the first use.
> 
> Fixes: 74eaa4a97e8e ("mm: consolidate GFP_NOFAIL checks in the allocator slowpath")
> Signed-off-by: Arnd Bergmann <arnd@...db.de>

Acked-by: David Rientjes <rientjes@...gle.com>