Commit d78f3853 authored by SeongJae Park's avatar SeongJae Park Committed by Linus Torvalds
Browse files

mm/damon/dbgfs: fix missed use of damon_dbgfs_lock 

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@kernel.org


Fixes: 75c1c2b5 ("mm/damon/dbgfs: support multiple contexts")
Signed-off-by: default avatarSeongJae Park <sj@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent db7a347b

mm/damon/dbgfs.c

+9 −3
Original line number Diff line number Diff line
@@ -877,12 +877,14 @@ static ssize_t dbgfs_monitor_on_write(struct file *file, 
		return -EINVAL;

	}



	mutex_lock(&damon_dbgfs_lock);

	if (!strncmp(kbuf, "on", count)) {

		int i;



		for (i = 0; i < dbgfs_nr_ctxs; i++) {

			if (damon_targets_empty(dbgfs_ctxs[i])) {

				kfree(kbuf);

				mutex_unlock(&damon_dbgfs_lock);

				return -EINVAL;

			}

		}
@@ -892,6 +894,7 @@ static ssize_t dbgfs_monitor_on_write(struct file *file, 
	} else {

		ret = -EINVAL;

	}

	mutex_unlock(&damon_dbgfs_lock);



	if (!ret)

		ret = count;
@@ -944,15 +947,16 @@ static int __init __damon_dbgfs_init(void) 


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;
@@ -963,6 +967,8 @@ static int __init damon_dbgfs_init(void) 
		pr_err("%s: dbgfs init failed\n", __func__);

	}



out:

	mutex_unlock(&damon_dbgfs_lock);

	return rc;

}