diff options
| author | Peter Zijlstra <peterz@infradead.org> | 2025-09-10 09:51:06 +0200 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2025-10-16 11:13:52 +0200 |
| commit | abfc01077df66593f128d966fdad1d042facc9ac (patch) | |
| tree | 5b0192685eee1a6b6595fb638de9919257b5ebca /kernel/kthread.c | |
| parent | 942b8db965006cf655d356162f7091a9238da94e (diff) | |
sched: Fix do_set_cpus_allowed() locking
All callers of do_set_cpus_allowed() only take p->pi_lock, which is
not sufficient to actually change the cpumask. Again, this is mostly
ok in these cases, but it results in unnecessarily complicated
reasoning.
Furthermore, there is no reason what so ever to not just take all the
required locks, so do just that.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Juri Lelli <juri.lelli@redhat.com>
Acked-by: Tejun Heo <tj@kernel.org>
Acked-by: Vincent Guittot <vincent.guittot@linaro.org>
Diffstat (limited to 'kernel/kthread.c')
| -rw-r--r-- | kernel/kthread.c | 15 |
1 files changed, 5 insertions, 10 deletions
diff --git a/kernel/kthread.c b/kernel/kthread.c index 31b072e8d427..832bd2afecc6 100644 --- a/kernel/kthread.c +++ b/kernel/kthread.c @@ -593,18 +593,16 @@ EXPORT_SYMBOL(kthread_create_on_node); static void __kthread_bind_mask(struct task_struct *p, const struct cpumask *mask, unsigned int state) { - unsigned long flags; - if (!wait_task_inactive(p, state)) { WARN_ON(1); return; } + scoped_guard (raw_spinlock_irqsave, &p->pi_lock) + do_set_cpus_allowed(p, mask); + /* It's safe because the task is inactive. */ - raw_spin_lock_irqsave(&p->pi_lock, flags); - do_set_cpus_allowed(p, mask); p->flags |= PF_NO_SETAFFINITY; - raw_spin_unlock_irqrestore(&p->pi_lock, flags); } static void __kthread_bind(struct task_struct *p, unsigned int cpu, unsigned int state) @@ -857,7 +855,6 @@ int kthread_affine_preferred(struct task_struct *p, const struct cpumask *mask) { struct kthread *kthread = to_kthread(p); cpumask_var_t affinity; - unsigned long flags; int ret = 0; if (!wait_task_inactive(p, TASK_UNINTERRUPTIBLE) || kthread->started) { @@ -882,10 +879,8 @@ int kthread_affine_preferred(struct task_struct *p, const struct cpumask *mask) list_add_tail(&kthread->hotplug_node, &kthreads_hotplug); kthread_fetch_affinity(kthread, affinity); - /* It's safe because the task is inactive. */ - raw_spin_lock_irqsave(&p->pi_lock, flags); - do_set_cpus_allowed(p, affinity); - raw_spin_unlock_irqrestore(&p->pi_lock, flags); + scoped_guard (raw_spinlock_irqsave, &p->pi_lock) + do_set_cpus_allowed(p, affinity); mutex_unlock(&kthreads_hotplug_lock); out: |