[PATCH] sched: Fix sched_getaffinity

[PATCH] sched: Fix sched_getaffinity

[Anton Blanchard]

taskset on 2.6.34-rc3 fails on one of my ppc64 test boxes with the following
error:

sched_getaffinity(0, 16, 0x10029650030) = -1 EINVAL (Invalid argument)

This box has 128 threads and 16 bytes is enough to cover it. Commit
cd3d8031eb4311e516329aee03c79a08333141f1 (sched: sched_getaffinity(): Allow
less than NR_CPUS length) is comparing this 16 bytes agains nr_cpu_ids.

Fix it by comparing nr_cpu_ids to the number of bits in the cpumask we pass in.

Signed-off-by: Anton Blanchard <anton@samba.org>
---

diff --git a/kernel/sched.c b/kernel/sched.c
index 49d2fa7..0c1ec87 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -4902,7 +4902,7 @@ SYSCALL_DEFINE3(sched_getaffinity, pid_t, pid, unsigned int, len,
 	int ret;
 	cpumask_var_t mask;
 
-	if (len < nr_cpu_ids)
+	if ((len * BITS_PER_BYTE) < nr_cpu_ids)
 		return -EINVAL;
 	if (len & (sizeof(unsigned long)-1))
 		return -EINVAL;

Re: [PATCH] sched: Fix sched_getaffinity

[KOSAKI Motohiro]

> 
> taskset on 2.6.34-rc3 fails on one of my ppc64 test boxes with the following
> error:
> 
> sched_getaffinity(0, 16, 0x10029650030) = -1 EINVAL (Invalid argument)
> 
> This box has 128 threads and 16 bytes is enough to cover it. Commit
> cd3d8031eb4311e516329aee03c79a08333141f1 (sched: sched_getaffinity(): Allow
> less than NR_CPUS length) is comparing this 16 bytes agains nr_cpu_ids.
> 
> Fix it by comparing nr_cpu_ids to the number of bits in the cpumask we pass in.
> 
> Signed-off-by: Anton Blanchard <anton@samba.org>

Oops, yes yes, thanks to correct my moron ;-) 
I'll stop all todays job and will get sleeping soon.
	Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>


> ---
> 
> diff --git a/kernel/sched.c b/kernel/sched.c
> index 49d2fa7..0c1ec87 100644
> --- a/kernel/sched.c
> +++ b/kernel/sched.c
> @@ -4902,7 +4902,7 @@ SYSCALL_DEFINE3(sched_getaffinity, pid_t, pid, unsigned int, len,
>  	int ret;
>  	cpumask_var_t mask;
>  
> -	if (len < nr_cpu_ids)
> +	if ((len * BITS_PER_BYTE) < nr_cpu_ids)
>  		return -EINVAL;
>  	if (len & (sizeof(unsigned long)-1))
>  		return -EINVAL;
> --
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[tip:sched/urgent] sched: Fix sched_getaffinity()

[tip-bot for Anton Blanchard]

Commit-ID:  84fba5ec91f11c0efb27d0ed6098f7447491f0df
Gitweb:     http://git.kernel.org/tip/84fba5ec91f11c0efb27d0ed6098f7447491f0df
Author:     Anton Blanchard <anton@samba.org>
AuthorDate: Tue, 6 Apr 2010 17:02:19 +1000
Committer:  Ingo Molnar <mingo@elte.hu>
CommitDate: Tue, 6 Apr 2010 10:01:35 +0200

sched: Fix sched_getaffinity()

taskset on 2.6.34-rc3 fails on one of my ppc64 test boxes with
the following error:

  sched_getaffinity(0, 16, 0x10029650030) = -1 EINVAL (Invalid argument)

This box has 128 threads and 16 bytes is enough to cover it.

Commit cd3d8031eb4311e516329aee03c79a08333141f1 (sched:
sched_getaffinity(): Allow less than NR_CPUS length) is
comparing this 16 bytes agains nr_cpu_ids.

Fix it by comparing nr_cpu_ids to the number of bits in the
cpumask we pass in.

Signed-off-by: Anton Blanchard <anton@samba.org>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Sharyathi Nagesh <sharyath@in.ibm.com>
Cc: Ulrich Drepper <drepper@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Jack Steiner <steiner@sgi.com>
Cc: Russ Anderson <rja@sgi.com>
Cc: Mike Travis <travis@sgi.com>
LKML-Reference: <20100406070218.GM5594@kryten>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
 kernel/sched.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/kernel/sched.c b/kernel/sched.c
index 528a105..eaf5c73 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -4902,7 +4902,7 @@ SYSCALL_DEFINE3(sched_getaffinity, pid_t, pid, unsigned int, len,
 	int ret;
 	cpumask_var_t mask;
 
-	if (len < nr_cpu_ids)
+	if ((len * BITS_PER_BYTE) < nr_cpu_ids)
 		return -EINVAL;
 	if (len & (sizeof(unsigned long)-1))
 		return -EINVAL;