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authorIngo Molnar <mingo@elte.hu>2007-12-04 17:04:39 +0100
committerIngo Molnar <mingo@elte.hu>2007-12-04 17:04:39 +0100
commit77034937dc4575ca0a76bf209838ecd39e804089 (patch)
tree96713ca12264ead56f859fd3619b27e49072456a
parent09b56adc98e0f8a21644fcb4d20ad367c3fceb55 (diff)
sched: fix crash in sys_sched_rr_get_interval()
Luiz Fernando N. Capitulino reported that sched_rr_get_interval() crashes for SCHED_OTHER tasks that are on an idle runqueue. The fix is to return a 0 timeslice for tasks that are on an idle runqueue. (and which are not running, obviously) this also shrinks the code a bit: text data bss dec hex filename 47903 3934 336 52173 cbcd sched.o.before 47885 3934 336 52155 cbbb sched.o.after Reported-by: Luiz Fernando N. Capitulino <lcapitulino@mandriva.com.br> Signed-off-by: Ingo Molnar <mingo@elte.hu>
-rw-r--r--kernel/sched.c14
1 files changed, 9 insertions, 5 deletions
diff --git a/kernel/sched.c b/kernel/sched.c
index 59ff6b140ed..b062856b946 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -4850,17 +4850,21 @@ long sys_sched_rr_get_interval(pid_t pid, struct timespec __user *interval)
if (retval)
goto out_unlock;
- if (p->policy == SCHED_FIFO)
- time_slice = 0;
- else if (p->policy == SCHED_RR)
+ /*
+ * Time slice is 0 for SCHED_FIFO tasks and for SCHED_OTHER
+ * tasks that are on an otherwise idle runqueue:
+ */
+ time_slice = 0;
+ if (p->policy == SCHED_RR) {
time_slice = DEF_TIMESLICE;
- else {
+ } else {
struct sched_entity *se = &p->se;
unsigned long flags;
struct rq *rq;
rq = task_rq_lock(p, &flags);
- time_slice = NS_TO_JIFFIES(sched_slice(cfs_rq_of(se), se));
+ if (rq->cfs.load.weight)
+ time_slice = NS_TO_JIFFIES(sched_slice(&rq->cfs, se));
task_rq_unlock(rq, &flags);
}
read_unlock(&tasklist_lock);