2023-02-02 15:16:47

by Greg KH

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

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 <[email protected]>
Cc: Yang Yingliang <[email protected]>
Cc: [email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
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

2023-02-03 08:13:31

by Yang Yingliang

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

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 <[email protected]>
> Cc: Yang Yingliang <[email protected]>
> Cc: [email protected]
> Signed-off-by: Greg Kroah-Hartman <[email protected]>

Reviewed-by: Yang Yingliang <[email protected]>