This is a note to let you know that I've just added the patch titled
mm/damon/sysfs: check DAMOS regions update progress from before_terminate()
to the 6.5-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-check-damos-regions-update-progress-from-before_terminate.patch
and it can be found in the queue-6.5 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 76b7069bcc89dec33f03eb08abee165d0306b754 Mon Sep 17 00:00:00 2001
From: SeongJae Park <sj@xxxxxxxxxx>
Date: Sat, 7 Oct 2023 20:04:32 +0000
Subject: mm/damon/sysfs: check DAMOS regions update progress from before_terminate()
From: SeongJae Park <sj@xxxxxxxxxx>
commit 76b7069bcc89dec33f03eb08abee165d0306b754 upstream.
DAMON_SYSFS can receive DAMOS tried regions update request while kdamond
is already out of the main loop and before_terminate callback
(damon_sysfs_before_terminate() in this case) is not yet called. And
damon_sysfs_handle_cmd() can further be finished before the callback is
invoked. Then, damon_sysfs_before_terminate() unlocks damon_sysfs_lock,
which is not locked by anyone. This happens because the callback function
assumes damon_sysfs_cmd_request_callback() should be called before it.
Check if the assumption was true before doing the unlock, to avoid this
problem.
Link: https://lkml.kernel.org/r/20231007200432.3110-1-sj@xxxxxxxxxx
Fixes: f1d13cacabe1 ("mm/damon/sysfs: implement DAMOS tried regions update command")
Signed-off-by: SeongJae Park <sj@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx> [6.2.x]
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
mm/damon/sysfs.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
--- a/mm/damon/sysfs.c
+++ b/mm/damon/sysfs.c
@@ -1202,6 +1202,8 @@ static int damon_sysfs_set_targets(struc
return 0;
}
+static bool damon_sysfs_schemes_regions_updating;
+
static void damon_sysfs_before_terminate(struct damon_ctx *ctx)
{
struct damon_target *t, *next;
@@ -1209,10 +1211,12 @@ static void damon_sysfs_before_terminate
/* damon_sysfs_schemes_update_regions_stop() might not yet called */
kdamond = damon_sysfs_cmd_request.kdamond;
- if (kdamond && damon_sysfs_cmd_request.cmd ==
+ if (kdamond && (damon_sysfs_cmd_request.cmd ==
DAMON_SYSFS_CMD_UPDATE_SCHEMES_TRIED_REGIONS &&
+ damon_sysfs_schemes_regions_updating) &&
ctx == kdamond->damon_ctx) {
damon_sysfs_schemes_update_regions_stop(ctx);
+ damon_sysfs_schemes_regions_updating = false;
mutex_unlock(&damon_sysfs_lock);
}
@@ -1331,7 +1335,6 @@ static int damon_sysfs_commit_input(stru
static int damon_sysfs_cmd_request_callback(struct damon_ctx *c)
{
struct damon_sysfs_kdamond *kdamond;
- static bool damon_sysfs_schemes_regions_updating;
int err = 0;
/* avoid deadlock due to concurrent state_store('off') */
Patches currently in stable-queue which might be from sj@xxxxxxxxxx are
queue-6.5/mm-damon-sysfs-check-damos-regions-update-progress-from-before_terminate.patch
