From 0bf5055d5d33133c3a7cc5e4032eeb0ba7832c44 Mon Sep 17 00:00:00 2001
From: SeongJae Park <sj@kernel.org>
Date: Mon, 6 Nov 2023 23:34:08 +0000
Subject: [PATCH] mm/damon/sysfs-schemes: handle tried region directory
allocation failure
commit ae636ae2bbfd9279f5681dbf320d1da817e52b68 upstream.
DAMON sysfs interface's before_damos_apply callback
(damon_sysfs_before_damos_apply()), which creates the DAMOS tried regions
for each DAMOS action applied region, is not handling the allocation
failure for the sysfs directory data. As a result, NULL pointer
derefeence is possible. Fix it by handling the case.
Link: https://lkml.kernel.org/r/20231106233408.51159-4-sj@kernel.org
Fixes: f1d13cacabe1 ("mm/damon/sysfs: implement DAMOS tried regions update command")
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: <stable@vger.kernel.org> [6.2+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
mm/damon/sysfs-schemes.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/mm/damon/sysfs-schemes.c b/mm/damon/sysfs-schemes.c
index 527e7d17eb3b..13e29fe065ab 100644
--- a/mm/damon/sysfs-schemes.c
+++ b/mm/damon/sysfs-schemes.c
@@ -1752,6 +1752,8 @@ static int damon_sysfs_before_damos_apply(struct damon_ctx *ctx,
return 0;
region = damon_sysfs_scheme_region_alloc(r);
+ if (!region)
+ return 0;
list_add_tail(®ion->list, &sysfs_regions->regions_list);
sysfs_regions->nr_regions++;
if (kobject_init_and_add(®ion->kobj,