+ mm-damon-sysfs-schemes-handle-tried-regions-sysfs-directory-allocation-failure.patch added to mm-hotfixes-unstable branch

[Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>]

The patch titled
     Subject: mm/damon/sysfs-schemes: handle tried regions sysfs directory allocation failure
has been added to the -mm mm-hotfixes-unstable branch.  Its filename is
     mm-damon-sysfs-schemes-handle-tried-regions-sysfs-directory-allocation-failure.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-damon-sysfs-schemes-handle-tried-regions-sysfs-directory-allocation-failure.patch

This patch will later appear in the mm-hotfixes-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: SeongJae Park <sj@xxxxxxxxxx>
Subject: mm/damon/sysfs-schemes: handle tried regions sysfs directory allocation failure
Date: Mon, 6 Nov 2023 23:34:07 +0000

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>
---

 mm/damon/sysfs-schemes.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/mm/damon/sysfs-schemes.c~mm-damon-sysfs-schemes-handle-tried-regions-sysfs-directory-allocation-failure
+++ a/mm/damon/sysfs-schemes.c
@@ -162,6 +162,9 @@ 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;
_

Patches currently in -mm which might be from sj@xxxxxxxxxx are

mm-damon-sysfs-check-error-from-damon_sysfs_update_target.patch
mm-damon-sysfs-schemes-handle-tried-regions-sysfs-directory-allocation-failure.patch
mm-damon-sysfs-schemes-handle-tried-region-directory-allocation-failure.patch