linux-kernel - [PATCH] devtmpfs: fix the dangling pointer of global devtmpfsd thread

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Date:   Mon, 27 Jun 2022 20:04:09 +0800
From:   Yangxi Xiang <xyangxi5@...il.com>
To:     linux-kernel@...r.kernel.org
Cc:     gregkh@...uxfoundation.org,
        "Rafael J. Wysocki" <rafael@...nel.org>,
        Yangxi Xiang <xyangxi5@...il.com>
Subject: [PATCH] devtmpfs: fix the dangling pointer of global devtmpfsd thread

When the devtmpfs fails to mount, a dangling pointer still remains in
global. Specifically, the err variable is passed by a pointer to the
devtmpfsd. When the devtmpfsd exits, it sets the error and completes the
setup_done. In this situation, the thread pointer is not set to null.
After the devtmpfsd exited, the devtmpfs can wakes up the destroyed
devtmpfsd thread by wake_up_process if a device change event comes.

Signed-off-by: Yangxi Xiang <xyangxi5@...il.com>
---
 drivers/base/devtmpfs.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/base/devtmpfs.c b/drivers/base/devtmpfs.c
index 8a3ddbae3b70..e4bffeabf344 100644
--- a/drivers/base/devtmpfs.c
+++ b/drivers/base/devtmpfs.c
@@ -482,6 +482,7 @@ int __init devtmpfs_init(void)
 	if (err) {
 		printk(KERN_ERR "devtmpfs: unable to create devtmpfs %i\n", err);
 		unregister_filesystem(&dev_fs_type);
+		thread = NULL;
 		return err;
 	}

-- 
2.17.1