From 2fd60da46da76948b8cc561ae8cc902209686253 Mon Sep 17 00:00:00 2001
From: Peng Wang <rocking@whu.edu.cn>
Date: Mon, 8 Jul 2019 23:16:11 +0800
Subject: [PATCH] kernfs: fix potential null pointer dereference
Get root safely after kn is ensureed to be not null.
Signed-off-by: Peng Wang <rocking@whu.edu.cn>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20190708151611.13242-1-rocking@whu.edu.cn
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
fs/kernfs/dir.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c
index a387534c95778..ddf537923a0af 100644
--- a/fs/kernfs/dir.c
+++ b/fs/kernfs/dir.c
@@ -430,7 +430,6 @@ struct kernfs_node *kernfs_get_active(struct kernfs_node *kn)
*/
void kernfs_put_active(struct kernfs_node *kn)
{
- struct kernfs_root *root = kernfs_root(kn);
int v;
if (unlikely(!kn))
@@ -442,7 +441,7 @@ void kernfs_put_active(struct kernfs_node *kn)
if (likely(v != KN_DEACTIVATED_BIAS))
return;
- wake_up_all(&root->deactivate_waitq);
+ wake_up_all(&kernfs_root(kn)->deactivate_waitq);
}
/**
--
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