| Message ID | 20201124155039.13804-12-will@kernel.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | An alternative series for asymmetric AArch32 systems | expand |
On Tuesday 24 Nov 2020 at 15:50:36 (+0000), Will Deacon wrote: > 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 arch_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. I guess mentioning here (or as a comment) the 'funny' behaviour we get with cpusets wouldn't hurt. But this is a sensible patch nonetheless so: Reviewed-by: Quentin Perret <qperret@google.com> Thanks, Quentin
diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 99992d0beb65..095deda50643 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -1877,6 +1877,7 @@ static int __set_cpus_allowed_ptr_locked(struct task_struct *p, struct rq_flags *rf) { const struct cpumask *cpu_valid_mask = cpu_active_mask; + const struct cpumask *cpu_allowed_mask = arch_task_cpu_possible_mask(p); unsigned int dest_cpu; int ret = 0; @@ -1887,6 +1888,9 @@ static int __set_cpus_allowed_ptr_locked(struct task_struct *p, * Kernel threads are allowed on online && !active CPUs */ cpu_valid_mask = cpu_online_mask; + } else if (!cpumask_subset(new_mask, cpu_allowed_mask)) { + ret = -EINVAL; + goto out; } /*
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 arch_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> --- kernel/sched/core.c | 4 ++++ 1 file changed, 4 insertions(+)