sched: Use rq->rd in sched_setaffinity() under RCU read lock

Probability of use-after-free isn't zero in this place. Signed-off-by: Kirill Tkhai <[email protected]> Signed-off-by: Peter Zijlstra (Intel) <[email protected]> Cc: <[email protected]> # v3.14+ Cc: Paul E. McKenney <[email protected]> Cc: Linus Torvalds <[email protected]> Link: http://lkml.kernel.org/r/20140922183636.11015.83611.stgit@localhost Signed-off-by: Ingo Molnar <[email protected]>
ddstreet · Sep 24, 2014 · f1e3a09 · f1e3a09
1 parent 16303ab
commit f1e3a09
Showing 1 changed file with 5 additions and 4 deletions.
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
@@ -4049,13 +4049,14 @@ long sched_setaffinity(pid_t pid, const struct cpumask *in_mask)
 	 * root_domain.
 	 */
 #ifdef CONFIG_SMP
-	if (task_has_dl_policy(p)) {
-		const struct cpumask *span = task_rq(p)->rd->span;
-
-		if (dl_bandwidth_enabled() && !cpumask_subset(span, new_mask)) {
+	if (task_has_dl_policy(p) && dl_bandwidth_enabled()) {
+		rcu_read_lock();
+		if (!cpumask_subset(task_rq(p)->rd->span, new_mask)) {
 			retval = -EBUSY;
+			rcu_read_unlock();
 			goto out_free_new_mask;
 		}
+		rcu_read_unlock();
 	}
 #endif
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