diff options
| author | Will Deacon | 2021-07-30 12:24:32 +0100 |
|---|---|---|
| committer | Peter Zijlstra | 2021-08-20 12:32:59 +0200 |
| commit | 234a503e670be01f72841be9fcf68dfb89a1fa8b (patch) | |
| tree | ee867fb4f0dc0afd94d240eb949e4d569b85e4d8 /kernel | |
| parent | 97c0054dbe2c3c59d1156fd233f2d44e91981c8e (diff) | |
sched: Reject CPU affinity changes based on task_cpu_possible_mask()
Reject explicit requests to change the affinity mask of a task via
set_cpus_allowed_ptr() if the requested mask is not a subset of the
mask returned by task_cpu_possible_mask(). This ensures that the
'cpus_mask' for a given task cannot contain CPUs which are incapable of
executing it, except in cases where the affinity is forced.
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Valentin Schneider <Valentin.Schneider@arm.com>
Reviewed-by: Quentin Perret <qperret@google.com>
Link: https://lore.kernel.org/r/20210730112443.23245-6-will@kernel.org
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/sched/core.c | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/kernel/sched/core.c b/kernel/sched/core.c index b9d4bae922a8..8cec0d24c88c 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -2709,7 +2709,9 @@ static int __set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask, u32 flags) { + const struct cpumask *cpu_allowed_mask = task_cpu_possible_mask(p); const struct cpumask *cpu_valid_mask = cpu_active_mask; + bool kthread = p->flags & PF_KTHREAD; unsigned int dest_cpu; struct rq_flags rf; struct rq *rq; @@ -2718,7 +2720,7 @@ static int __set_cpus_allowed_ptr(struct task_struct *p, rq = task_rq_lock(p, &rf); update_rq_clock(rq); - if (p->flags & PF_KTHREAD || is_migration_disabled(p)) { + if (kthread || is_migration_disabled(p)) { /* * Kernel threads are allowed on online && !active CPUs, * however, during cpu-hot-unplug, even these might get pushed @@ -2732,6 +2734,11 @@ static int __set_cpus_allowed_ptr(struct task_struct *p, cpu_valid_mask = cpu_online_mask; } + if (!kthread && !cpumask_subset(new_mask, cpu_allowed_mask)) { + ret = -EINVAL; + goto out; + } + /* * Must re-check here, to close a race against __kthread_bind(), * sched_setaffinity() is not guaranteed to observe the flag. |