diff options
| author | Tejun Heo <tj@kernel.org> | 2013-03-19 13:45:20 -0700 |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2013-03-19 13:45:20 -0700 |
| commit | 14a40ffccd6163bbcd1d6f32b28a88ffe6149fc6 (patch) | |
| tree | eb61e5bf7b64c3e67f3e33fe6b07fde4ee1d4d43 /kernel/cgroup.c | |
| parent | 2e109a2855bf6cf675a8b74dbd89b6492e8def42 (diff) | |
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/cgroup.c')
| -rw-r--r-- | kernel/cgroup.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/kernel/cgroup.c b/kernel/cgroup.c index a32f9432666..3852d926322 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -2224,11 +2224,11 @@ retry_find_task: tsk = tsk->group_leader; /* - * Workqueue threads may acquire PF_THREAD_BOUND and become + * Workqueue threads may acquire PF_NO_SETAFFINITY and become * trapped in a cpuset, or RT worker may be born in a cgroup * with no rt_runtime allocated. Just say no. */ - if (tsk == kthreadd_task || (tsk->flags & PF_THREAD_BOUND)) { + if (tsk == kthreadd_task || (tsk->flags & PF_NO_SETAFFINITY)) { ret = -EINVAL; rcu_read_unlock(); goto out_unlock_cgroup; |