From: J. Bruce Fields Date: Thu, 3 Mar 2016 00:36:21 +0000 (-0800) Subject: nfsd: fix deadlock secinfo+readdir compound X-Git-Tag: firefly_0821_release~176^2~4^2~50^2~21 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=56fb92d684cc51baf3a421a3ac19af441a52f413;p=firefly-linux-kernel-4.4.55.git 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 Signed-off-by: Greg Kroah-Hartman --- diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c index a9f096c7e99f..7d5351cd67fb 100644 --- a/fs/nfsd/nfs4proc.c +++ b/fs/nfsd/nfs4proc.c @@ -877,6 +877,7 @@ nfsd4_secinfo(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate, &exp, &dentry); if (err) return err; + fh_unlock(&cstate->current_fh); if (d_really_is_negative(dentry)) { exp_put(exp); err = nfserr_noent;