[PATCH 1/1] workqueue: swap set_cpus_allowed_ptr() andPF_NO_SETAFFINITY

From: Oleg Nesterov
Date: Thu Nov 14 2013 - 06:54:59 EST


Move the setting of PF_NO_SETAFFINITY up before set_cpus_allowed()
in create_worker(). Otherwise userland can change ->cpus_allowed
in between.

Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
---
kernel/workqueue.c | 8 ++++----
1 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 987293d..775af74 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -1736,16 +1736,16 @@ static struct worker *create_worker(struct worker_pool *pool)
if (IS_ERR(worker->task))
goto fail;

+ set_user_nice(worker->task, pool->attrs->nice);
+
+ /* prevent userland from meddling with cpumask of workqueue workers */
+ worker->task->flags |= PF_NO_SETAFFINITY;
/*
* set_cpus_allowed_ptr() will fail if the cpumask doesn't have any
* online CPUs. It'll be re-applied when any of the CPUs come up.
*/
- set_user_nice(worker->task, pool->attrs->nice);
set_cpus_allowed_ptr(worker->task, pool->attrs->cpumask);

- /* prevent userland from meddling with cpumask of workqueue workers */
- worker->task->flags |= PF_NO_SETAFFINITY;
-
/*
* The caller is responsible for ensuring %POOL_DISASSOCIATED
* remains stable across this function. See the comments above the
--
1.5.5.1


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