[PATCH 6.4 211/800] ocfs2: Fix use of slab data with sendpage

Greg Kroah-Hartman
2023-07-16T20:04:06Z

From: David Howells <dhowells@redhat.com>

[ Upstream commit 86d7bd6e66e9925f0f04a7bcf3c92c05fdfefb5a ]

ocfs2 uses kzalloc() to allocate buffers for o2net_hand, o2net_keep_req and
o2net_keep_resp and then passes these to sendpage. This isn't really
allowed as the lifetime of slab objects is not controlled by page ref -
though in this case it will probably work. sendmsg() with MSG_SPLICE_PAGES
will, however, print a warning and give an error.

Fix it to use folio_alloc() instead to allocate a buffer for the handshake
message, keepalive request and reply messages.

Fixes: 98211489d414 ("[PATCH] OCFS2: The Second Oracle Cluster Filesystem")
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Mark Fasheh <mark@fasheh.com>
cc: Kurt Hackel <kurt.hackel@oracle.com>
cc: Joel Becker <jlbec@evilplan.org>
cc: Joseph Qi <joseph.qi@linux.alibaba.com>
cc: ocfs2-devel@oss.oracle.com
Link: https://lore.kernel.org/r/20230623225513.2732256-14-dhowells@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/ocfs2/cluster/tcp.c | 23 ++++++++++++-----------
1 file changed, 12 insertions(+), 11 deletions(-)

diff --git a/fs/ocfs2/cluster/tcp.c b/fs/ocfs2/cluster/tcp.c
index aecbd712a00cf..929a1133bc180 100644
--- a/fs/ocfs2/cluster/tcp.c
+++ b/fs/ocfs2/cluster/tcp.c
@@ -2087,18 +2087,24 @@ void o2net_stop_listening(struct o2nm_node *node)

int o2net_init(void)
{
+ struct folio *folio;
+ void *p;
unsigned long i;

o2quo_init();
-
o2net_debugfs_init();

- o2net_hand = kzalloc(sizeof(struct o2net_handshake), GFP_KERNEL);
- o2net_keep_req = kzalloc(sizeof(struct o2net_msg), GFP_KERNEL);
- o2net_keep_resp = kzalloc(sizeof(struct o2net_msg), GFP_KERNEL);
- if (!o2net_hand || !o2net_keep_req || !o2net_keep_resp)
+ folio = folio_alloc(GFP_KERNEL | __GFP_ZERO, 0);
+ if (!folio)
goto out;

+ p = folio_address(folio);
+ o2net_hand = p;
+ p += sizeof(struct o2net_handshake);
+ o2net_keep_req = p;
+ p += sizeof(struct o2net_msg);
+ o2net_keep_resp = p;
+
o2net_hand->protocol_version = cpu_to_be64(O2NET_PROTOCOL_VERSION);
o2net_hand->connector_id = cpu_to_be64(1);

@@ -2124,9 +2130,6 @@ int o2net_init(void)
return 0;

out:
- kfree(o2net_hand);
- kfree(o2net_keep_req);
- kfree(o2net_keep_resp);
o2net_debugfs_exit();
o2quo_exit();
return -ENOMEM;
@@ -2135,8 +2138,6 @@ int o2net_init(void)
void o2net_exit(void)
{
o2quo_exit();
- kfree(o2net_hand);
- kfree(o2net_keep_req);
- kfree(o2net_keep_resp);
o2net_debugfs_exit();
+ folio_put(virt_to_folio(o2net_hand));
}
--
2.39.2