From: SeongJae Park <sj@kernel.org> mainline inclusion from mainline-v6.7-rc2 commit ae636ae2bbfd9279f5681dbf320d1da817e52b68 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IBDTU7 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- 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: Ze Zuo <zuoze1@huawei.com> --- 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 18f9dac92ace..575c0ba34b90 100644 --- a/mm/damon/sysfs-schemes.c +++ b/mm/damon/sysfs-schemes.c @@ -1283,6 +1283,8 @@ static int damon_sysfs_before_damos_apply(struct damon_ctx *ctx, sysfs_regions = sysfs_schemes->schemes_arr[schemes_idx]->tried_regions; 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, -- 2.25.1