From: Dave Wysochanski <dwysocha@redhat.com>
Date: Fri, 11 Dec 2020 10:12:51 +0000 (-0500)
Subject: NFS4: Fix use-after-free in trace_event_raw_event_nfs4_set_lock
X-Git-Tag: v4.14.217~28
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=905e5e439fb533ccb03958716e9e8697cf02e641;p=users%2Fdwmw2%2Flinux.git

NFS4: Fix use-after-free in trace_event_raw_event_nfs4_set_lock

commit 3d1a90ab0ed93362ec8ac85cf291243c87260c21 upstream.

It is only safe to call the tracepoint before rpc_put_task() because
'data' is freed inside nfs4_lock_release (rpc_release).

Fixes: 48c9579a1afe ("Adding stateid information to tracepoints")
Signed-off-by: Dave Wysochanski <dwysocha@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 9f2ba4874f10f..cbfea2c7d5167 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -6395,9 +6395,9 @@ static int _nfs4_do_setlk(struct nfs4_state *state, int cmd, struct file_lock *f
 					data->arg.new_lock_owner, ret);
 	} else
 		data->cancelled = true;
+	trace_nfs4_set_lock(fl, state, &data->res.stateid, cmd, ret);
 	rpc_put_task(task);
 	dprintk("%s: done, ret = %d!\n", __func__, ret);
-	trace_nfs4_set_lock(fl, state, &data->res.stateid, cmd, ret);
 	return ret;
 }