Re: linux-next: build warning after merge of the random tree

From: Stephen Rothwell
Date: Mon Sep 23 2013 - 00:43:00 EST


Hi Ted,

On Mon, 23 Sep 2013 14:39:24 +1000 Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx> wrote:
>
> After merging the random tree, today's linux-next build (powerpc64
> allnoconfig) produced this warning:
>
> In file included from include/linux/kernel.h:10:0,
> from include/linux/sched.h:15,
> from include/linux/utsname.h:5,
> from drivers/char/random.c:238:
> drivers/char/random.c: In function 'add_interrupt_randomness':
> include/linux/bitops.h:96:2: warning: 'input[3]' may be used uninitialized in this function [-Wmaybe-uninitialized]
> return (word << shift) | (word >> (32 - shift));
> ^
> drivers/char/random.c:827:10: note: 'input[3]' was declared here
> __u32 input[4], cycles = random_get_entropy();
> ^
> In file included from include/linux/kernel.h:10:0,
> from include/linux/sched.h:15,
> from include/linux/utsname.h:5,
> from drivers/char/random.c:238:
> include/linux/bitops.h:96:2: warning: 'input[2]' may be used uninitialized in this function [-Wmaybe-uninitialized]
> return (word << shift) | (word >> (32 - shift));
> ^
> drivers/char/random.c:827:10: note: 'input[2]' was declared here
> __u32 input[4], cycles = random_get_entropy();
> ^
>
> Probably introduced by commit d5693ae494f2 ("random: speed up the
> fast_mix function by a factor of four").

i386 defconfig produces similar (to make testing easier).

--
Cheers,
Stephen Rothwell sfr@xxxxxxxxxxxxxxxx

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