> On Sep 30, 2021, at 10:16 AM, J. Bruce Fields <bfields@xxxxxxxxxxxx> wrote: > > On Thu, Sep 30, 2021 at 03:48:42AM +0000, Ho, Patrick wrote: >>> 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. > > Whoops, thanks for catching this. I assume Chuck will pick it up. Applied to the for-next branch at git://git.kernel.org/pub/scm/linux/kernel/git/cel/linux.git > Acked-by: J. Bruce Fields <bfields@xxxxxxxxxx> > > --b. > >> >> 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 -- Chuck Lever