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authorWaiman Long <longman@redhat.com>2023-01-15 14:31:22 -0500
committerIngo Molnar <mingo@kernel.org>2023-01-16 10:07:25 +0100
commit5657c116783545fb49cd7004994c187128552b12 (patch)
tree4d8906a3c05a5b56455deccd6008a126e157684c /kernel
parentda07d2f9c153e457e845d4dcfdd13568d71d18a4 (diff)
sched/core: Fix NULL pointer access fault in sched_setaffinity() with non-SMP configs
The kernel commit 9a5418bc48ba ("sched/core: Use kfree_rcu() in do_set_cpus_allowed()") introduces a bug for kernels built with non-SMP configs. Calling sched_setaffinity() on such a uniprocessor kernel will cause cpumask_copy() to be called with a NULL pointer leading to general protection fault. This is not really a problem in real use cases as there aren't that many uniprocessor kernel configs in use and calling sched_setaffinity() on such a uniprocessor system doesn't make sense. Fix this problem by making sure cpumask_copy() will not be called in such a case. Fixes: 9a5418bc48ba ("sched/core: Use kfree_rcu() in do_set_cpus_allowed()") Reported-by: kernel test robot <yujie.liu@intel.com> Signed-off-by: Waiman Long <longman@redhat.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Acked-by: Peter Zijlstra <peterz@infradead.org> Link: https://lore.kernel.org/r/20230115193122.563036-1-longman@redhat.com
Diffstat (limited to 'kernel')
-rw-r--r--kernel/sched/core.c10
1 files changed, 8 insertions, 2 deletions
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index bb1ee6d7bdde..e838feb6adc5 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -8290,12 +8290,18 @@ long sched_setaffinity(pid_t pid, const struct cpumask *in_mask)
if (retval)
goto out_put_task;
+ /*
+ * With non-SMP configs, user_cpus_ptr/user_mask isn't used and
+ * alloc_user_cpus_ptr() returns NULL.
+ */
user_mask = alloc_user_cpus_ptr(NUMA_NO_NODE);
- if (IS_ENABLED(CONFIG_SMP) && !user_mask) {
+ if (user_mask) {
+ cpumask_copy(user_mask, in_mask);
+ } else if (IS_ENABLED(CONFIG_SMP)) {
retval = -ENOMEM;
goto out_put_task;
}
- cpumask_copy(user_mask, in_mask);
+
ac = (struct affinity_context){
.new_mask = in_mask,
.user_mask = user_mask,