[PATCH v6 09/21] sched: Reject CPU affinity changes based on task_cpu_possible_mask()
From: Will Deacon <will@kernel.org>
Date: 2021-05-18 09:49:02
Also in:
linux-arm-kernel, lkml
Subsystem:
scheduler, the rest · Maintainers:
Ingo Molnar, Peter Zijlstra, Juri Lelli, Vincent Guittot, Linus Torvalds
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. Reviewed-by: Quentin Perret <redacted> Signed-off-by: Will Deacon <will@kernel.org> --- kernel/sched/core.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 482f7fdca0e8..21da3d7f9e47 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c@@ -2350,6 +2350,7 @@ static int __set_cpus_allowed_ptr(struct task_struct *p, u32 flags) { const struct cpumask *cpu_valid_mask = cpu_active_mask; + const struct cpumask *cpu_allowed_mask = task_cpu_possible_mask(p); unsigned int dest_cpu; struct rq_flags rf; struct rq *rq;
@@ -2370,6 +2371,9 @@ static int __set_cpus_allowed_ptr(struct task_struct *p, * set_cpus_allowed_common() and actually reset p->cpus_ptr. */ cpu_valid_mask = cpu_online_mask; + } else if (!cpumask_subset(new_mask, cpu_allowed_mask)) { + ret = -EINVAL; + goto out; } /*
--
2.31.1.751.gd2f1c929bd-goog