[PATCH] kernel/fail_function: fix memory leak with using debugfs_lookup()

[PATCH] kernel/fail_function: fix memory leak with using debugfs_lookup()

[Greg Kroah-Hartman]

When calling debugfs_lookup() the result must have dput() called on it,
otherwise the memory will leak over time.  To make things simpler, just
call debugfs_lookup_and_remove() instead which handles all of the logic
at once.

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Yang Yingliang <yangyingliang@huawei.com>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 kernel/fail_function.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/kernel/fail_function.c b/kernel/fail_function.c
index a7ccd2930c5f..d971a0189319 100644
--- a/kernel/fail_function.c
+++ b/kernel/fail_function.c
@@ -163,10 +163,7 @@ static void fei_debugfs_add_attr(struct fei_attr *attr)
 
 static void fei_debugfs_remove_attr(struct fei_attr *attr)
 {
-	struct dentry *dir;
-
-	dir = debugfs_lookup(attr->kp.symbol_name, fei_debugfs_dir);
-	debugfs_remove_recursive(dir);
+	debugfs_lookup_and_remove(attr->kp.symbol_name, fei_debugfs_dir);
 }
 
 static int fei_kprobe_handler(struct kprobe *kp, struct pt_regs *regs)
-- 
2.39.1

Re: [PATCH] kernel/fail_function: fix memory leak with using debugfs_lookup()

[Yang Yingliang]

On 2023/2/2 23:16, Greg Kroah-Hartman wrote:
> When calling debugfs_lookup() the result must have dput() called on it,
> otherwise the memory will leak over time.  To make things simpler, just
> call debugfs_lookup_and_remove() instead which handles all of the logic
> at once.
>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Yang Yingliang <yangyingliang@huawei.com>
> Cc: linux-kernel@vger.kernel.org
> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Reviewed-by: Yang Yingliang <yangyingliang@huawei.com>