+ mm-damon-dbgfs-fix-memory-leak-when-using.patch added to mm-hotfixes-unstable branch

Andrew Morton
2022-09-02T19:26:37Z

The patch titled
Subject: mm/damon/dbgfs: fix memory leak when using
has been added to the -mm mm-hotfixes-unstable branch. Its filename is
mm-damon-dbgfs-fix-memory-leak-when-using.patch

This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-damon-dbgfs-fix-memory-leak-when-using.patch

This patch will later appear in the mm-hotfixes-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Subject: mm/damon/dbgfs: fix memory leak when using
Date: Fri, 2 Sep 2022 19:11:49 +0000

When calling debugfs_lookup() the result must have dput() called on it,
otherwise the memory will leak over time. Fix this up by properly calling
dput().

Link: https://lkml.kernel.org/r/20220902191149.112434-1-sj@kernel.org
Fixes: 75c1c2b53c78b ("mm/damon/dbgfs: support multiple contexts")
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

mm/damon/dbgfs.c | 19 ++++++++++++++-----
1 file changed, 14 insertions(+), 5 deletions(-)

--- a/mm/damon/dbgfs.c~mm-damon-dbgfs-fix-memory-leak-when-using
+++ a/mm/damon/dbgfs.c
@@ -884,6 +884,7 @@ static int dbgfs_rm_context(char *name)
struct dentry *root, *dir, **new_dirs;
struct damon_ctx **new_ctxs;
int i, j;
+ int ret = 0;

if (damon_nr_running_ctxs())
return -EBUSY;
@@ -898,14 +899,16 @@ static int dbgfs_rm_context(char *name)

new_dirs = kmalloc_array(dbgfs_nr_ctxs - 1, sizeof(*dbgfs_dirs),
GFP_KERNEL);
- if (!new_dirs)
- return -ENOMEM;
+ if (!new_dirs) {
+ ret = -ENOMEM;
+ goto out_dput;
+ }

new_ctxs = kmalloc_array(dbgfs_nr_ctxs - 1, sizeof(*dbgfs_ctxs),
GFP_KERNEL);
if (!new_ctxs) {
- kfree(new_dirs);
- return -ENOMEM;
+ ret = -ENOMEM;
+ goto out_new_dirs;
}

for (i = 0, j = 0; i < dbgfs_nr_ctxs; i++) {
@@ -925,7 +928,13 @@ static int dbgfs_rm_context(char *name)
dbgfs_ctxs = new_ctxs;
dbgfs_nr_ctxs--;

- return 0;
+ goto out_dput;
+
+out_new_dirs:
+ kfree(new_dirs);
+out_dput:
+ dput(dir);
+ return ret;
}

static ssize_t dbgfs_rm_context_write(struct file *file,
_

Patches currently in -mm which might be from gregkh@linuxfoundation.org are

mm-damon-dbgfs-fix-memory-leak-when-using.patch