From: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
debugfs_lookup()
Date: Fri, 2 Sep 2022 14:56:31 +0200 [thread overview]
Message-ID: <20220902125631.128329-1-gregkh@xxxxxxxxxxxxxxxxxxx> (raw)
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().
Fixes: 75c1c2b53c78b ("mm/damon/dbgfs: support multiple contexts")
Cc: <stable@xxxxxxxxxxxxxxx> # 5.15.x
Cc: SeongJae Park <sj@xxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: damon@xxxxxxxxxxxxxxx
Cc: linux-mm@xxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: SeongJae Park <sj@xxxxxxxxxx>
---
Changes from v1
(https://lore.kernel.org/damon/20220902125631.128329-1-gregkh@xxxxxxxxxxxxxxxxxxx/)
- Call dput() for failure-return case (Andrew Morton)
mm/damon/dbgfs.c | 19 ++++++++++++++-----
1 file changed, 14 insertions(+), 5 deletions(-)
diff --git a/mm/damon/dbgfs.c b/mm/damon/dbgfs.c
index 3b55a1b219b5..652a94deafe3 100644
--- a/mm/damon/dbgfs.c
+++ b/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,
--
2.25.1
