Commit e117ff11 authored by Waiman Long's avatar Waiman Long Committed by Tejun Heo
Browse files

cgroup/cpuset: Prevent NULL pointer access in free_tmpmasks() 



Commit 5806b3d0 ("cpuset: decouple tmpmasks and cpumasks freeing in
cgroup") separates out the freeing of tmpmasks into a new free_tmpmask()
helper but removes the NULL pointer check in the process. Unfortunately a
NULL pointer can be passed to free_tmpmasks() in cpuset_handle_hotplug()
if cpuset v1 is active. This can cause segmentation fault and crash
the kernel.

Fix that by adding the NULL pointer check to free_tmpmasks().

Fixes: 5806b3d0 ("cpuset: decouple tmpmasks and cpumasks freeing in cgroup")
Reported-by: default avatarAshay Jaiswal <quic_ashayj@quicinc.com>
Closes: https://lore.kernel.org/lkml/20250902-cpuset-free-on-condition-v1-1-f46ffab53eac@quicinc.com/


Signed-off-by: default avatarWaiman Long <longman@redhat.com>
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
parent 3b0dec68

kernel/cgroup/cpuset.c

+3 −0
Original line number Diff line number Diff line
@@ -484,6 +484,9 @@ static inline int alloc_tmpmasks(struct tmpmasks *tmp) 
 */

static inline void free_tmpmasks(struct tmpmasks *tmp)

{

	if (!tmp)

		return;



	free_cpumask_var(tmp->new_cpus);

	free_cpumask_var(tmp->addmask);

	free_cpumask_var(tmp->delmask);