Re: [PATCH] sched: fix tsk->pi_lock isn't held when do_set_cpus_allowed()

From: Wanpeng Li
Date: Tue Aug 25 2015 - 04:38:27 EST

On 8/25/15 4:30 PM, Ingo Molnar wrote:
* Wanpeng Li <> wrote:

--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c
@@ -2376,8 +2376,12 @@ void cpuset_cpus_allowed(struct task_struct *tsk, struct cpumask *pmask)
void cpuset_cpus_allowed_fallback(struct task_struct *tsk)
+ unsigned long flags;
+ raw_spin_lock_irqsave(&tsk->pi_lock, flags);
do_set_cpus_allowed(tsk, task_cs(tsk)->effective_cpus);
+ raw_spin_lock_irqsave(&tsk->pi_lock, flags);
Just curious, Will introduce deadlock after acquire lock twice? ;)
Could you point out where acquires lock twice?
In the code you quote?

Shame me, sorry for sending out the wrong version. I fix in it soon in v2.

Wanpeng Li



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