From: Jeff Layton <jlayton@kernel.org>
Date: Mon, 27 Mar 2023 06:21:37 -0400
Subject: [PATCH] nfsd: call op_release, even when op_func returns an error
Git-commit: 15a8b55dbb1ba154d82627547c5761cac884d810
Patch-mainline: v6.3
References: git-fixes

For ops with "trivial" replies, nfsd4_encode_operation will shortcut
most of the encoding work and skip to just marshalling up the status.
One of the things it skips is calling op_release. This could cause a
memory leak in the layoutget codepath if there is an error at an
inopportune time.

Have the compound processing engine always call op_release, even when
op_func sets an error in op->status. With this change, we also need
nfsd4_block_get_device_info_scsi to set the gd_device pointer to NULL
on error to avoid a double free.

Reported-by: Zhi Li <yieli@redhat.com>
Link: https://bugzilla.redhat.com/show_bug.cgi?id=2181403
Fixes: 34b1744c91cc ("nfsd4: define ->op_release for compound ops")
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Acked-by: NeilBrown <neilb@suse.com>

---
 fs/nfsd/nfs4xdr.c |   11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -5313,10 +5313,8 @@ nfsd4_encode_operation(struct nfsd4_comp
 	__be32 *p;
 
 	p = xdr_reserve_space(xdr, 8);
-	if (!p) {
-		WARN_ON_ONCE(1);
-		return;
-	}
+	if (!p)
+		goto release;
 	*p++ = cpu_to_be32(op->opnum);
 	post_err_offset = xdr->buf->len;
 
@@ -5331,8 +5329,6 @@ nfsd4_encode_operation(struct nfsd4_comp
 	op->status = encoder(resp, op->status, &op->u);
 	if (op->status)
 		trace_nfsd_compound_encode_err(rqstp, op->opnum, op->status);
-	if (opdesc && opdesc->op_release)
-		opdesc->op_release(&op->u);
 	xdr_commit_encode(xdr);
 
 	/* nfsd4_check_resp_size guarantees enough room for error status */
@@ -5374,6 +5370,9 @@ nfsd4_encode_operation(struct nfsd4_comp
 status:
 	/* Note that op->status is already in network byte order: */
 	write_bytes_to_xdr_buf(xdr->buf, post_err_offset - 4, &op->status, 4);
+release:
+	if (opdesc && opdesc->op_release)
+		opdesc->op_release(&op->u);
 }
 
 /*