This is a note to let you know that I've just added the patch titled
mm/damon/dbgfs: protect targets destructions with kdamond_lock
to the 5.15-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-dbgfs-protect-targets-destructions-with-kdamond_lock.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 34796417964b8d0aef45a99cf6c2d20cebe33733 Mon Sep 17 00:00:00 2001
From: SeongJae Park <sj@xxxxxxxxxx>
Date: Fri, 24 Dec 2021 21:12:54 -0800
Subject: mm/damon/dbgfs: protect targets destructions with kdamond_lock
From: SeongJae Park <sj@xxxxxxxxxx>
commit 34796417964b8d0aef45a99cf6c2d20cebe33733 upstream.
DAMON debugfs interface iterates current monitoring targets in
'dbgfs_target_ids_read()' while holding the corresponding
'kdamond_lock'. However, it also destructs the monitoring targets in
'dbgfs_before_terminate()' without holding the lock. This can result in
a use_after_free bug. This commit avoids the race by protecting the
destruction with the corresponding 'kdamond_lock'.
Link: https://lkml.kernel.org/r/20211221094447.2241-1-sj@xxxxxxxxxx
Reported-by: Sangwoo Bae <sangwoob@xxxxxxxxxx>
Fixes: 4bc05954d007 ("mm/damon: implement a debugfs-based user space interface")
Signed-off-by: SeongJae Park <sj@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx> [5.15.x]
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
mm/damon/dbgfs.c | 2 ++
1 file changed, 2 insertions(+)
--- a/mm/damon/dbgfs.c
+++ b/mm/damon/dbgfs.c
@@ -309,10 +309,12 @@ static int dbgfs_before_terminate(struct
if (!targetid_is_pid(ctx))
return 0;
+ mutex_lock(&ctx->kdamond_lock);
damon_for_each_target_safe(t, next, ctx) {
put_pid((struct pid *)t->id);
damon_destroy_target(t);
}
+ mutex_unlock(&ctx->kdamond_lock);
return 0;
}
Patches currently in stable-queue which might be from sj@xxxxxxxxxx are
queue-5.15/mm-damon-dbgfs-protect-targets-destructions-with-kdamond_lock.patch
