cgroup/cpuset: Fix a memory leak in update_exclusive_cpumask()

commit 66f40b926dd249f74334a22162c09e7ec1ec5b07 upstream.

Fix a possible memory leak in update_exclusive_cpumask() by moving the
alloc_cpumasks() down after the validate_change() check which can fail
and still before the temporary cpumasks are needed.

Fixes: e2ffe502ba45 ("cgroup/cpuset: Add cpuset.cpus.exclusive for v2")
Reported-and-tested-by: Mirsad Todorovac <mirsad.todorovac@alu.hr>
Closes: https://lore.kernel.org/lkml/14915689-27a3-4cd8-80d2-9c30d0c768b6@alu.unizg.hr
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: stable@vger.kernel.org # v6.7+
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
index 942346bd9cdb609ae856eeb1ba62985c032df4c7..ffe0e0029437b4517e7b683b86b482cb99fbfa73 100644 (file)
--- a/kernel/cgroup/cpuset.c
+++ b/kernel/cgroup/cpuset.c
@@ -2502,9 +2502,6 @@ static int update_exclusive_cpumask(struct cpuset *cs, struct cpuset *trialcs,
        if (cpumask_equal(cs->exclusive_cpus, trialcs->exclusive_cpus))
                return 0;
 
-       if (alloc_cpumasks(NULL, &tmp))
-               return -ENOMEM;
-
        if (*buf)
                compute_effective_exclusive_cpumask(trialcs, NULL);
 
@@ -2519,6 +2516,9 @@ static int update_exclusive_cpumask(struct cpuset *cs, struct cpuset *trialcs,
        if (retval)
                return retval;
 
+       if (alloc_cpumasks(NULL, &tmp))
+               return -ENOMEM;
+
        if (old_prs) {
                if (cpumask_empty(trialcs->effective_xcpus)) {
                        invalidate = true;