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| author | Waiman Long <longman@redhat.com> | 2023-01-15 14:31:22 -0500 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2023-01-16 10:07:25 +0100 |
| commit | 5657c116783545fb49cd7004994c187128552b12 (patch) | |
| tree | 4d8906a3c05a5b56455deccd6008a126e157684c /kernel | |
| parent | da07d2f9c153e457e845d4dcfdd13568d71d18a4 (diff) | |
| download | linux-stable-5657c116783545fb49cd7004994c187128552b12.tar.gz linux-stable-5657c116783545fb49cd7004994c187128552b12.tar.bz2 linux-stable-5657c116783545fb49cd7004994c187128552b12.zip | |
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.c | 10 |
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, |