From b9382e29ca538b879645899ce45d652a304e2ed2 Mon Sep 17 00:00:00 2001 From: Jeff Layton Date: Sat, 25 Jan 2025 20:13:18 -0500 Subject: [PATCH] nfsd: validate the nfsd_serv pointer before calling svc_wake_up nfsd_file_dispose_list_delayed can be called from the filecache laundrette, which is shut down after the nfsd threads are shut down and the nfsd_serv pointer is cleared. If nn->nfsd_serv is NULL then there are no threads to wake. Ensure that the nn->nfsd_serv pointer is non-NULL before calling svc_wake_up in nfsd_file_dispose_list_delayed. This is safe since the svc_serv is not freed until after the filecache laundrette is cancelled. Reported-by: Salvatore Bonaccorso Closes: https://bugs.debian.org/1093734 Fixes: ffb402596147 ("nfsd: Don't leave work of closing files to a work queue") Cc: stable@vger.kernel.org Signed-off-by: Jeff Layton Reviewed-by: NeilBrown Signed-off-by: Chuck Lever --- fs/nfsd/filecache.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/fs/nfsd/filecache.c b/fs/nfsd/filecache.c index a1cdba42c4fa..78f4b5573b90 100644 --- a/fs/nfsd/filecache.c +++ b/fs/nfsd/filecache.c @@ -445,11 +445,20 @@ nfsd_file_dispose_list_delayed(struct list_head *dispose) struct nfsd_file, nf_gc); struct nfsd_net *nn = net_generic(nf->nf_net, nfsd_net_id); struct nfsd_fcache_disposal *l = nn->fcache_disposal; + struct svc_serv *serv; spin_lock(&l->lock); list_move_tail(&nf->nf_gc, &l->freeme); spin_unlock(&l->lock); - svc_wake_up(nn->nfsd_serv); + + /* + * The filecache laundrette is shut down after the + * nn->nfsd_serv pointer is cleared, but before the + * svc_serv is freed. + */ + serv = nn->nfsd_serv; + if (serv) + svc_wake_up(serv); } }