This is a note to let you know that I've just added the patch titled
mm/damon/sysfs-schemes: skip stats update if the scheme directory is removed
to the 6.0-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
mm-damon-sysfs-schemes-skip-stats-update-if-the-scheme-directory-is-removed.patch
and it can be found in the queue-6.0 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 8468b486612c808c9e337708d66a435498f1735c Mon Sep 17 00:00:00 2001
From: SeongJae Park <sj@xxxxxxxxxx>
Date: Mon, 14 Nov 2022 17:55:52 +0000
Subject: mm/damon/sysfs-schemes: skip stats update if the scheme directory is removed
From: SeongJae Park <sj@xxxxxxxxxx>
commit 8468b486612c808c9e337708d66a435498f1735c upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
mm/damon/sysfs.c | 4 ++++
1 file changed, 4 insertions(+)
--- a/mm/damon/sysfs.c
+++ b/mm/damon/sysfs.c
@@ -2342,6 +2342,10 @@ static int damon_sysfs_upd_schemes_stats
damon_for_each_scheme(scheme, ctx) {
struct damon_sysfs_stats *sysfs_stats;
+ /* user could have 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 stable-queue which might be from sj@xxxxxxxxxx are
queue-6.0/mm-damon-sysfs-schemes-skip-stats-update-if-the-scheme-directory-is-removed.patch
