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SubjectRe: [1/3] futex: fix compiler warnings in exit_robust_list
Hey Darren,

On Wed, Oct 27, 2010 at 09:54:24PM -0000, Darren Hart wrote:
> The following commit introduced a compiler warning:
> Commit 1dcc41bb037533839753df983d31778b30b67d93
> futex: Change 3rd arg of fetch_robust_entry() to unsigned int*
>
> The following archs/compiler versions all report:
> kernel/futex.c: In function ‘exit_robust_list’:
> kernel/futex.c:2492: warning: ‘next_pi’ may be used uninitialized in this function
>
> x86_64
> gcc (Ubuntu 4.4.3-4ubuntu5) 4.4.3
> gcc (GCC) 4.4.4 20100630 (Red Hat 4.4.4-10)
> gcc (Ubuntu/Linaro 4.4.4-14ubuntu5) 4.4.5
>
> sh
> sh-linux-gnu-gcc (Sourcery G++ Lite 4.3-143) 4.3.3
You can add

arm
arm-1136jfs-linux-gnueabi-gcc (OSELAS.Toolchain-1.99.3) 4.3.2

if you want.

>
> The code path really can't result in next_pi pi being unitialized (or should
> not), but let's keep the build clean. Assign next_pi = 0 to avoid the warnings.
>
> Signed-off-by: Darren Hart <dvhart@linux.intel.com>
> Tested-by: Matt Fleming <matt@console-pimps.org>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Ingo Molnar <mingo@elte.hu>
> CC: Eric Dumazet <eric.dumazet@gmail.com>
> CC: John Kacur <jkacur@redhat.com>
>
> ---
> kernel/futex.c | 2 +-
> 1 files changed, 1 insertions(+), 1 deletions(-)
>
> diff --git a/kernel/futex.c b/kernel/futex.c
> index a118bf1..78715cb 100644
> --- a/kernel/futex.c
> +++ b/kernel/futex.c
> @@ -2489,7 +2489,7 @@ void exit_robust_list(struct task_struct *curr)
> {
> struct robust_list_head __user *head = curr->robust_list;
> struct robust_list __user *entry, *next_entry, *pending;
> - unsigned int limit = ROBUST_LIST_LIMIT, pi, next_pi, pip;
> + unsigned int limit = ROBUST_LIST_LIMIT, pi, next_pi = 0, pip;
I'd prefer

+ unsigned int limit = ROBUST_LIST_LIMIT, pi, uninitialized_var(next_pi), pip;

(modulo line length). This makes your change more explicit.

Best regards
Uwe

--
Pengutronix e.K. | Uwe Kleine-König |
Industrial Linux Solutions | http://www.pengutronix.de/ |
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