The patch titled
Subject: mm/damon/sysfs-schemes: skip stats update if the scheme directory is removed
has been added to the -mm mm-hotfixes-unstable branch. Its filename is
mm-damon-sysfs-schemes-skip-stats-update-if-the-scheme-directory-is-removed.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-skip-stats-update-if-the-scheme-directory-is-removed.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: skip stats update if the scheme directory is removed
Date: Mon, 14 Nov 2022 17:55:52 +0000
A DAMON sysfs interface user can start DAMON with a scheme, remove the
sysfs directory for the scheme, and then ask update of the scheme's stats.
Because the schemes stats update logic isn't aware of the situation, it
results in an invalid memory access. Fix the bug by checking if the
scheme sysfs directory exists.
Link: https://lkml.kernel.org/r/20221114175552.1951-1-sj@xxxxxxxxxx
Fixes: 0ac32b8affb5 ("mm/damon/sysfs: support DAMOS stats")
Signed-off-by: SeongJae Park <sj@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx> [v5.18]
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/damon/sysfs.c | 4 ++++
1 file changed, 4 insertions(+)
--- a/mm/damon/sysfs.c~mm-damon-sysfs-schemes-skip-stats-update-if-the-scheme-directory-is-removed
+++ a/mm/damon/sysfs.c
@@ -2339,6 +2339,10 @@ static int damon_sysfs_upd_schemes_stats
damon_for_each_scheme(scheme, ctx) {
struct damon_sysfs_stats *sysfs_stats;
+ /* user could removed the scheme sysfs dir */
+ if (schemes_idx >= sysfs_schemes->nr)
+ break;
+
sysfs_stats = sysfs_schemes->schemes_arr[schemes_idx++]->stats;
sysfs_stats->nr_tried = scheme->stat.nr_tried;
sysfs_stats->sz_tried = scheme->stat.sz_tried;
_
Patches currently in -mm which might be from sj@xxxxxxxxxx are
mm-damon-sysfs-schemes-skip-stats-update-if-the-scheme-directory-is-removed.patch
docs-admin-guide-mm-damon-usage-describe-the-rules-of-sysfs-region-directories.patch
docs-admin-guide-mm-damon-usage-fix-wrong-usage-example-of-init_regions-file.patch
mm-damon-core-add-a-callback-for-scheme-target-regions-check.patch
mm-damon-sysfs-schemes-implement-schemes-tried_regions-directory.patch
mm-damon-sysfs-schemes-implement-scheme-region-directory.patch
mm-damon-sysfs-implement-damos-tried-regions-update-command.patch
mm-damon-sysfs-implement-damos-tried-regions-update-command-fix.patch
mm-damon-sysfs-schemes-implement-damos-tried-regions-clear-command.patch
mm-damon-sysfs-schemes-implement-damos-tried-regions-clear-command-fix.patch
tools-selftets-damon-sysfs-test-tried_regions-directory-existence.patch
docs-admin-guide-mm-damon-usage-document-schemes-s-tried_regions-sysfs-directory.patch
docs-abi-damon-document-schemes-s-tried_regions-sysfs-directory.patch
selftests-damon-test-non-context-inputs-to-rm_contexts-file.patch
