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authorTejun Heo <tj@kernel.org>2013-03-19 13:45:20 -0700
committerTejun Heo <tj@kernel.org>2013-03-19 13:45:20 -0700
commit14a40ffccd6163bbcd1d6f32b28a88ffe6149fc6 (patch)
treeeb61e5bf7b64c3e67f3e33fe6b07fde4ee1d4d43 /kernel/kthread.c
parent2e109a2855bf6cf675a8b74dbd89b6492e8def42 (diff)
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op-kernel-dev-14a40ffccd6163bbcd1d6f32b28a88ffe6149fc6.tar.gz
sched: replace PF_THREAD_BOUND with PF_NO_SETAFFINITY
PF_THREAD_BOUND was originally used to mark kernel threads which were bound to a specific CPU using kthread_bind() and a task with the flag set allows cpus_allowed modifications only to itself. Workqueue is currently abusing it to prevent userland from meddling with cpus_allowed of workqueue workers. What we need is a flag to prevent userland from messing with cpus_allowed of certain kernel tasks. In kernel, anyone can (incorrectly) squash the flag, and, for worker-type usages, restricting cpus_allowed modification to the task itself doesn't provide meaningful extra proection as other tasks can inject work items to the task anyway. This patch replaces PF_THREAD_BOUND with PF_NO_SETAFFINITY. sched_setaffinity() checks the flag and return -EINVAL if set. set_cpus_allowed_ptr() is no longer affected by the flag. This will allow simplifying workqueue worker CPU affinity management. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Ingo Molnar <mingo@kernel.org> Reviewed-by: Lai Jiangshan <laijs@cn.fujitsu.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'kernel/kthread.c')
-rw-r--r--kernel/kthread.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/kthread.c b/kernel/kthread.c
index 691dc2e..a2fbbb7 100644
--- a/kernel/kthread.c
+++ b/kernel/kthread.c
@@ -260,7 +260,7 @@ static void __kthread_bind(struct task_struct *p, unsigned int cpu)
{
/* It's safe because the task is inactive. */
do_set_cpus_allowed(p, cpumask_of(cpu));
- p->flags |= PF_THREAD_BOUND;
+ p->flags |= PF_NO_SETAFFINITY;
}
/**
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