[PATCH] sched: fix SCHED_FIFO bug in sys_sched_rr_get_interval()

The introduction of SCHED_BATCH scheduling class with a value of 3 means
that the expression (p->policy & SCHED_FIFO) will return true if policy
is SCHED_BATCH or SCHED_FIFO.

Unfortunately, this expression is used in sys_sched_rr_get_interval()
and in the absence of a comment to say that this is intentional I
presume that it is unintentional and erroneous.

The fix is to change the expression to (p->policy == SCHED_FIFO).

Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/kernel/sched.c b/kernel/sched.c
index f06d059..cfaf3fa 100644 (file)
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -4247,7 +4247,7 @@ long sys_sched_rr_get_interval(pid_t pid, struct timespec __user *interval)
        if (retval)
                goto out_unlock;
 
-       jiffies_to_timespec(p->policy & SCHED_FIFO ?
+       jiffies_to_timespec(p->policy == SCHED_FIFO ?
                                0 : task_timeslice(p), &t);
        read_unlock(&tasklist_lock);
        retval = copy_to_user(interval, &t, sizeof(t)) ? -EFAULT : 0;