nfsd: fix error handling of register_pernet_subsys() in init_nfsd()
authorPatrick Ho <Patrick.Ho@netapp.com>
Sat, 21 Aug 2021 06:56:26 +0000 (02:56 -0400)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Wed, 13 Oct 2021 08:04:24 +0000 (10:04 +0200)
commit12d4b179022ac7d07aa263b46159779536b3c6a6
tree50bd1064d54a533172bf1ba5b144febc73e68978
parent1bc2f315a215585f8bc07257542e67373c86e801
nfsd: fix error handling of register_pernet_subsys() in init_nfsd()

commit 1d625050c7c2dd877e108e382b8aaf1ae3cfe1f4 upstream.

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@vger.kernel.org
Signed-off-by: Patrick Ho <Patrick.Ho@netapp.com>
Acked-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
fs/nfsd/nfsctl.c