Commit df8d829b authored by Shardul Bankar's avatar Shardul Bankar Committed by Chuck Lever
Browse files

nfsd: fix memory leak in nfsd_create_serv error paths 



When nfsd_create_serv() calls percpu_ref_init() to initialize
nn->nfsd_net_ref, it allocates both a percpu reference counter
and a percpu_ref_data structure (64 bytes). However, if the
function fails later due to svc_create_pooled() returning NULL
or svc_bind() returning an error, these allocations are not
cleaned up, resulting in a memory leak.

The leak manifests as:
- Unreferenced percpu allocation (8 bytes per CPU)
- Unreferenced percpu_ref_data structure (64 bytes)

Fix this by adding percpu_ref_exit() calls in both error paths
to properly clean up the percpu_ref_init() allocations.

This patch fixes the percpu_ref leak in nfsd_create_serv() seen
as an auxiliary leak in syzbot report 099461f8558eb0a1f4f3; the
prepare_creds() and vsock-related leaks in the same report
remain to be addressed separately.

Reported-by: default avatar <syzbot+099461f8558eb0a1f4f3@syzkaller.appspotmail.com>
Link: https://syzkaller.appspot.com/bug?extid=099461f8558eb0a1f4f3


Fixes: 47e98814 ("nfsd: add nfsd_serv_try_get and nfsd_serv_put")
Signed-off-by: default avatarShardul Bankar <shardul.b@mpiricsoftware.com>
Reviewed-by: default avatarJeff Layton <jlayton@kernel.org>
Signed-off-by: default avatarChuck Lever <chuck.lever@oracle.com>
parent ebae1028

fs/nfsd/nfssvc.c

+4 −1
Original line number Diff line number Diff line
@@ -615,12 +615,15 @@ int nfsd_create_serv(struct net *net) 
	serv = svc_create_pooled(nfsd_programs, ARRAY_SIZE(nfsd_programs),

				 &nn->nfsd_svcstats,

				 nfsd_max_blksize, nfsd);

	if (serv == NULL)

	if (serv == NULL) {

		percpu_ref_exit(&nn->nfsd_net_ref);

		return -ENOMEM;

	}



	error = svc_bind(serv, net);

	if (error < 0) {

		svc_destroy(&serv);

		percpu_ref_exit(&nn->nfsd_net_ref);

		return error;

	}

	spin_lock(&nfsd_notifier_lock);