[PATCH 6.6 284/530] mm/damon/sysfs-schemes: handle tried regions sysfs directory allocation failure

[Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>]

6.6-stable review patch.  If anyone has any objections, please let me know.

------------------

From: SeongJae Park <sj@xxxxxxxxxx>

commit 84055688b6bc075c92a88e2d6c3ad26ab93919f9 upstream.

DAMOS tried regions sysfs directory allocation function
(damon_sysfs_scheme_regions_alloc()) is not handling the memory allocation
failure.  In the case, the code will dereference NULL pointer.  Handle the
failure to avoid such invalid access.

Link: https://lkml.kernel.org/r/20231106233408.51159-3-sj@xxxxxxxxxx
Fixes: 9277d0367ba1 ("mm/damon/sysfs-schemes: implement scheme region directory")
Signed-off-by: SeongJae Park <sj@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>	[6.2+]
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 mm/damon/sysfs-schemes.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/mm/damon/sysfs-schemes.c
+++ b/mm/damon/sysfs-schemes.c
@@ -126,6 +126,9 @@ damon_sysfs_scheme_regions_alloc(void)
 	struct damon_sysfs_scheme_regions *regions = kmalloc(sizeof(*regions),
 			GFP_KERNEL);
 
+	if (!regions)
+		return NULL;
+
 	regions->kobj = (struct kobject){};
 	INIT_LIST_HEAD(&regions->regions_list);
 	regions->nr_regions = 0;