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authorThomas Gleixner <tglx@linutronix.de>2009-12-09 10:15:11 +0000
committerIngo Molnar <mingo@elte.hu>2009-12-14 17:11:35 +0100
commit1a551ae715825bb2a2107a2dd68de024a1fa4e32 (patch)
tree03f29f6a37be1eea125994aee5d34b4daf804a20 /kernel/sched.c
parent23f5d142519621b16cf2b378cf8adf4dcf01a616 (diff)
downloadlwn-1a551ae715825bb2a2107a2dd68de024a1fa4e32.tar.gz
lwn-1a551ae715825bb2a2107a2dd68de024a1fa4e32.zip
sched: Use rcu in sched_get_rr_param()
read_lock(&tasklist_lock) does not protect sys_sched_get_rr_param() against a concurrent update of the policy or scheduler parameters as do_sched_scheduler() does not take the tasklist_lock. The access to task->sched_class->get_rr_interval is protected by task_rq_lock(task). Use rcu_read_lock() to protect find_task_by_vpid() and prevent the task struct from going away. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> LKML-Reference: <20091209100706.862897167@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/sched.c')
-rw-r--r--kernel/sched.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/kernel/sched.c b/kernel/sched.c
index 79893123325c..db5c26692dd5 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -6873,7 +6873,7 @@ SYSCALL_DEFINE2(sched_rr_get_interval, pid_t, pid,
return -EINVAL;
retval = -ESRCH;
- read_lock(&tasklist_lock);
+ rcu_read_lock();
p = find_process_by_pid(pid);
if (!p)
goto out_unlock;
@@ -6886,13 +6886,13 @@ SYSCALL_DEFINE2(sched_rr_get_interval, pid_t, pid,
time_slice = p->sched_class->get_rr_interval(rq, p);
task_rq_unlock(rq, &flags);
- read_unlock(&tasklist_lock);
+ rcu_read_unlock();
jiffies_to_timespec(time_slice, &t);
retval = copy_to_user(interval, &t, sizeof(t)) ? -EFAULT : 0;
return retval;
out_unlock:
- read_unlock(&tasklist_lock);
+ rcu_read_unlock();
return retval;
}