This is a note to let you know that I've just added the patch titled
mm/damon/dbgfs: fix missed use of damon_dbgfs_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-fix-missed-use-of-damon_dbgfs_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 d78f3853f831eee46c6dbe726debf3be9e9c0d05 Mon Sep 17 00:00:00 2001
From: SeongJae Park <sj@xxxxxxxxxx>
Date: Fri, 19 Nov 2021 16:43:52 -0800
Subject: mm/damon/dbgfs: fix missed use of damon_dbgfs_lock
From: SeongJae Park <sj@xxxxxxxxxx>
commit d78f3853f831eee46c6dbe726debf3be9e9c0d05 upstream.
DAMON debugfs is supposed to protect dbgfs_ctxs, dbgfs_nr_ctxs, and
dbgfs_dirs using damon_dbgfs_lock. However, some of the code is
accessing the variables without the protection. This fixes it by
protecting all such accesses.
Link: https://lkml.kernel.org/r/20211110145758.16558-3-sj@xxxxxxxxxx
Fixes: 75c1c2b53c78 ("mm/damon/dbgfs: support multiple contexts")
Signed-off-by: SeongJae Park <sj@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
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 | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)
--- a/mm/damon/dbgfs.c
+++ b/mm/damon/dbgfs.c
@@ -538,12 +538,14 @@ static ssize_t dbgfs_monitor_on_write(st
return -EINVAL;
}
+ mutex_lock(&damon_dbgfs_lock);
if (!strncmp(kbuf, "on", count))
err = damon_start(dbgfs_ctxs, dbgfs_nr_ctxs);
else if (!strncmp(kbuf, "off", count))
err = damon_stop(dbgfs_ctxs, dbgfs_nr_ctxs);
else
err = -EINVAL;
+ mutex_unlock(&damon_dbgfs_lock);
if (err)
ret = err;
@@ -596,15 +598,16 @@ static int __init __damon_dbgfs_init(voi
static int __init damon_dbgfs_init(void)
{
- int rc;
+ int rc = -ENOMEM;
+ mutex_lock(&damon_dbgfs_lock);
dbgfs_ctxs = kmalloc(sizeof(*dbgfs_ctxs), GFP_KERNEL);
if (!dbgfs_ctxs)
- return -ENOMEM;
+ goto out;
dbgfs_ctxs[0] = dbgfs_new_ctx();
if (!dbgfs_ctxs[0]) {
kfree(dbgfs_ctxs);
- return -ENOMEM;
+ goto out;
}
dbgfs_nr_ctxs = 1;
@@ -615,6 +618,8 @@ static int __init damon_dbgfs_init(void)
pr_err("%s: dbgfs init failed\n", __func__);
}
+out:
+ mutex_unlock(&damon_dbgfs_lock);
return rc;
}
Patches currently in stable-queue which might be from sj@xxxxxxxxxx are
queue-5.15/mm-damon-dbgfs-fix-missed-use-of-damon_dbgfs_lock.patch
queue-5.15/mm-damon-dbgfs-use-__gfp_nowarn-for-user-specified-size-buffer-allocation.patch
