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Commit 31605683 authored by Thomas Gleixner's avatar Thomas Gleixner Committed by Ingo Molnar
Browse files

sched: Protect task->cpus_allowed access in sched_getaffinity() 



sched_getaffinity() is not protected against a concurrent
modification of the tasks affinity.

Serialize the access with task_rq_lock(task).

Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Acked-by: default avatarPeter Zijlstra <peterz@infradead.org>
LKML-Reference: <20091208202026.769251187@linutronix.de>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 6ad4c188

kernel/sched.c

+4 −0
Original line number Diff line number Diff line
@@ -6631,6 +6631,8 @@ SYSCALL_DEFINE3(sched_setaffinity, pid_t, pid, unsigned int, len, 
long sched_getaffinity(pid_t pid, struct cpumask *mask)

{

	struct task_struct *p;

	unsigned long flags;

	struct rq *rq;

	int retval;



	get_online_cpus();
@@ -6645,7 +6647,9 @@ long sched_getaffinity(pid_t pid, struct cpumask *mask) 
	if (retval)

		goto out_unlock;



	rq = task_rq_lock(p, &flags);

	cpumask_and(mask, &p->cpus_allowed, cpu_online_mask);

	task_rq_unlock(rq, &flags);



out_unlock:

	read_unlock(&tasklist_lock);