[057/139] sched: Fix sched_getaffinity()

[Greg KH]

2.6.33-stable review patch.  If anyone has any objections, please let us know.

------------------

From: Anton Blanchard <anton@xxxxxxxxx>

commit 84fba5ec91f11c0efb27d0ed6098f7447491f0df upstream.

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@xxxxxxxxx>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>
Cc: Sharyathi Nagesh <sharyath@xxxxxxxxxx>
Cc: Ulrich Drepper <drepper@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Jack Steiner <steiner@xxxxxxx>
Cc: Russ Anderson <rja@xxxxxxx>
Cc: Mike Travis <travis@xxxxxxx>
LKML-Reference: <20100406070218.GM5594@kryten>
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

---
 kernel/sched.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -6717,7 +6717,7 @@ SYSCALL_DEFINE3(sched_getaffinity, pid_t
 	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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