sched: Fix sched_getaffinity()

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@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>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/kernel/sched.c b/kernel/sched.c
index c89db3bbd01f035d1855775f6c85bafe6c45fd86..f2f5a5f9e87e940792cb03ff20186ee51f2c5f00 100644 (file)
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -6717,7 +6717,7 @@ 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;