>From 7417896fcc7aea645fa0b89f39fa55979251dca3 Mon Sep 17 00:00:00 2001
From: Patrick Ho <Patrick.Ho@xxxxxxxxxx>
Date: Sat, 21 Aug 2021 02:56:26 -0400
Subject: [PATCH] nfsd: fix error handling of register_pernet_subsys() in
init_nfsd()
init_nfsd() should not unregister pernet subsys if the register fails
but should instead unwind from the last successful operation which is
register_filesystem().
Unregistering a failed register_pernet_subsys() call can result in
a kernel GPF as revealed by programmatically injecting an error in
register_pernet_subsys().
Verified the fix handled failure gracefully with no lingering nfsd
entry in /proc/filesystems. This change was introduced by the commit
bd5ae9288d64 ("nfsd: register pernet ops last, unregister first"),
the original error handling logic was correct.
Fixes: bd5ae9288d64 ("nfsd: register pernet ops last, unregister first")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Patrick Ho <Patrick.Ho@xxxxxxxxxx>
---
fs/nfsd/nfsctl.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
index c2c3d9077dc5..09ae1a0873d0 100644
--- a/fs/nfsd/nfsctl.c
+++ b/fs/nfsd/nfsctl.c
@@ -1545,7 +1545,7 @@ static int __init init_nfsd(void)
goto out_free_all;
return 0;
out_free_all:
- unregister_pernet_subsys(&nfsd_net_ops);
+ unregister_filesystem(&nfsd_fs_type);
out_free_exports:
remove_proc_entry("fs/nfs/exports", NULL);
remove_proc_entry("fs/nfs", NULL);
--
2.17.1
