| From f1e3a0932f3a9554371792a7daaf1e0eb19f66d5 Mon Sep 17 00:00:00 2001 |
| From: Kirill Tkhai <ktkhai@parallels.com> |
| Date: Mon, 22 Sep 2014 22:36:36 +0400 |
| Subject: sched: Use rq->rd in sched_setaffinity() under RCU read lock |
| |
| From: Kirill Tkhai <ktkhai@parallels.com> |
| |
| commit f1e3a0932f3a9554371792a7daaf1e0eb19f66d5 upstream. |
| |
| Probability of use-after-free isn't zero in this place. |
| |
| Signed-off-by: Kirill Tkhai <ktkhai@parallels.com> |
| Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> |
| Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> |
| Cc: Linus Torvalds <torvalds@linux-foundation.org> |
| Link: http://lkml.kernel.org/r/20140922183636.11015.83611.stgit@localhost |
| Signed-off-by: Ingo Molnar <mingo@kernel.org> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| kernel/sched/core.c | 9 +++++---- |
| 1 file changed, 5 insertions(+), 4 deletions(-) |
| |
| --- a/kernel/sched/core.c |
| +++ b/kernel/sched/core.c |
| @@ -4008,13 +4008,14 @@ long sched_setaffinity(pid_t pid, const |
| * 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_unlock; |
| } |
| + rcu_read_unlock(); |
| } |
| #endif |
| again: |
