From a34207e99ce196675d059f1b01baa50850fe7832 Mon Sep 17 00:00:00 2001 From: "J. Bruce Fields" Date: Wed, 2 Mar 2016 16:36:21 -0800 Subject: [PATCH] nfsd: fix deadlock secinfo+readdir compound commit 2f6fc056e899bd0144a08da5cacaecbe8997cd74 upstream. nfsd_lookup_dentry exits with the parent filehandle locked. fh_put also unlocks if necessary (nfsd filehandle locking is probably too lenient), so it gets unlocked eventually, but if the following op in the compound needs to lock it again, we can deadlock. A fuzzer ran into this; normal clients don't send a secinfo followed by a readdir in the same compound. Signed-off-by: J. Bruce Fields [bwh: Backported to 3.16: adjust context] Signed-off-by: Ben Hutchings --- fs/nfsd/nfs4proc.c | 1 + 1 file changed, 1 insertion(+) diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c index 5d3031ecb1dfd..5432605cce7d8 100644 --- a/fs/nfsd/nfs4proc.c +++ b/fs/nfsd/nfs4proc.c @@ -880,6 +880,7 @@ nfsd4_secinfo(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate, &exp, &dentry); if (err) return err; + fh_unlock(&cstate->current_fh); if (dentry->d_inode == NULL) { exp_put(exp); err = nfserr_noent; -- 2.47.3