[Devel] [PATCH RHEL7 COMMIT] ms/devtmpfs: fix the dangling pointer of global devtmpfsd thread

[Konstantin Khorenko]

The commit is pushed to "branch-rh7-3.10.0-1160.80.1.vz7.190.x-ovz" and will appear at https://src.openvz.org/scm/ovz/vzkernel.git
after rh7-3.10.0-1160.80.1.vz7.190.1
------>
commit a334df16a83a71f6176ae3264481aa7d99f2cac3
Author: Alexander Atanasov <alexander.atanasov at virtuozzo.com>
Date:   Mon Nov 28 21:49:33 2022 +0200

    ms/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 at gmail.com>
     Link: https://lore.kernel.org/r/20220627120409.11174-1-xyangxi5@gmail.com
     Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
    
    (mainstream commit 31c779f293b343577690c01369a5019ca6ec5de9)
    https://jira.sw.ru/browse/PSBM-142996
    Signed-off-by: Alexander Atanasov <alexander.atanasov at virtuozzo.com>
---
 drivers/base/devtmpfs.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/base/devtmpfs.c b/drivers/base/devtmpfs.c
index 8aefc2dc63a1..eb064072414a 100644
--- a/drivers/base/devtmpfs.c
+++ b/drivers/base/devtmpfs.c
@@ -485,12 +485,12 @@ int __init devtmpfs_init(void)
 		wait_for_completion(&setup_done);
 	} else {
 		err = PTR_ERR(thread);
-		thread = NULL;
 	}
 
 	if (err) {
 		printk(KERN_ERR "devtmpfs: unable to create devtmpfs %i\n", err);
 		unregister_filesystem(&dev_fs_type);
+		thread = NULL;
 		return err;
 	}