From: Thomas Gleixner <t...@linutronix.de>
If the PID encoded into the clock id is 0 then the target is either the
calling thread itself or the process to which it belongs.
If the current thread encodes its own PID on a process wide clock then
there is no reason not to treat it in the same way as the PID=0 case.
Signed-off-by: Thomas Gleixner <t...@linutronix.de>
Reviewed-by: Frederic Weisbecker <frede...@kernel.org>
---
V2: Remove the extra same_thread_group() check which is pointless.
---
kernel/time/posix-cpu-timers.c | 14 ++++++++------
1 file changed, 8 insertions(+), 6 deletions(-)
--- a/kernel/time/posix-cpu-timers.c
+++ b/kernel/time/posix-cpu-timers.c
@@ -90,18 +90,20 @@ static struct task_struct *lookup_task(c
} else {
/*
+ * Timer is going to be attached to a process. If p is
+ * current then treat it like the PID=0 case above.
+ * This also avoids the ptrace overhead.
+ */
+ if (p == current)
+ return current->group_leader;
+
+ /*
* Process wide timers need the group leader because they
* take a reference on it and store the task pointer until
* the timer is destroyed.
*/
if (!has_group_leader_pid(p))
return NULL;
-
- /*
- * Avoid the ptrace overhead when this is current's process
- */
- if (same_thread_group(p, current))
- return p;
}
/* Decide based on the ptrace permissions. */
