Re: [PATCH] mm/compaction: Fix warning of 'flags' may be used uninitialized

From: David Rientjes <rientjes@google.com>
To: Xiubo Li <Li.Xiubo@freescale.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Arnd Bergmann <arnd@arndb.de>,
	vbabka@suse.cz, mgorman@suse.de, minchan@kernel.org,
	linux-mm@kvack.org
Subject: Re: [PATCH] mm/compaction: Fix warning of 'flags' may be used uninitialized
Date: Wed, 10 Sep 2014 11:50:41 -0700 (PDT)	[thread overview]
Message-ID: <alpine.DEB.2.02.1409101149500.27173@chino.kir.corp.google.com> (raw)
In-Reply-To: <1410329540-40708-1-git-send-email-Li.Xiubo@freescale.com>

On Wed, 10 Sep 2014, Xiubo Li wrote:

> C      mm/compaction.o
> mm/compaction.c: In function isolate_freepages_block:
> mm/compaction.c:364:37: warning: flags may be used uninitialized in
> this function [-Wmaybe-uninitialized]
>        && compact_unlock_should_abort(&cc->zone->lock, flags,
>                                      ^
> In file included from include/linux/irqflags.h:15:0,
>                  from ./arch/arm/include/asm/bitops.h:27,
>                  from include/linux/bitops.h:33,
>                  from include/linux/kernel.h:10,
>                  from include/linux/list.h:8,
>                  from include/linux/preempt.h:10,
>                  from include/linux/spinlock.h:50,
>                  from include/linux/swap.h:4,
>                  from mm/compaction.c:10:
> mm/compaction.c: In function isolate_migratepages_block:
> ./arch/arm/include/asm/irqflags.h:152:2: warning: flags may be used
> uninitialized in this function [-Wmaybe-uninitialized]
>   asm volatile(
>   ^
> mm/compaction.c:576:16: note: flags as declared here
>   unsigned long flags;
>                 ^
> 
> Signed-off-by: Xiubo Li <Li.Xiubo@freescale.com>

Arnd Bergmann already sent a patch for this to use uninitialized_var() 
privately but it didn't get cc'd to any mailing list, sorry.

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