[PATCH 6.6 001/529] NFSD: Fix crash in nfsd4_read_release()

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

6.6-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Chuck Lever <chuck.lever@oracle.com>

commit abb1f08a2121dd270193746e43b2a9373db9ad84 upstream.

When tracing is enabled, the trace_nfsd_read_done trace point
crashes during the pynfs read.testNoFh test.

Fixes: 15a8b55dbb1b ("nfsd: call op_release, even when op_func returns an error")
Cc: stable@vger.kernel.org
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 fs/nfsd/nfs4proc.c |    7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -978,10 +978,11 @@ nfsd4_read(struct svc_rqst *rqstp, struc
 static void
 nfsd4_read_release(union nfsd4_op_u *u)
 {
-	if (u->read.rd_nf)
+	if (u->read.rd_nf) {
+		trace_nfsd_read_done(u->read.rd_rqstp, u->read.rd_fhp,
+				     u->read.rd_offset, u->read.rd_length);
 		nfsd_file_put(u->read.rd_nf);
-	trace_nfsd_read_done(u->read.rd_rqstp, u->read.rd_fhp,
-			     u->read.rd_offset, u->read.rd_length);
+	}
 }
 
 static __be32