[PATCH 6.18 143/198] smb: server: avoid double-free in smb_direct_free_sendmsg after smb_direct_flush_send_list()

Greg Kroah-Hartman
2026-04-20T16:04:06Z

From: Stefan Metzmacher <metze@samba.org>

commit 84ff995ae826aa6bbcc6c7b9ea569ff67c021d72 upstream.

smb_direct_flush_send_list() already calls smb_direct_free_sendmsg(),
so we should not call it again after post_sendmsg()
moved it to the batch list.

Reported-by: Ruikai Peng <ruikai@pwno.io>
Closes: https://lore.kernel.org/linux-cifs/CAFD3drNOSJ05y3A+jNXSDxW-2w09KHQ0DivhxQ_pcc7immVVOQ@mail.gmail.com/
Fixes: 34abd408c8ba ("smb: server: make use of smbdirect_socket.send_io.bcredits")
Cc: stable@kernel.org
Cc: Steve French <smfrench@gmail.com>
Cc: Tom Talpey <tom@talpey.com>
Cc: Ruikai Peng <ruikai@pwno.io>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: linux-cifs@vger.kernel.org
Cc: samba-technical@lists.samba.org
Cc: security@kernel.org
Signed-off-by: Stefan Metzmacher <metze@samba.org>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Acked-by: Paulo Alcantara (Red Hat) <pc@manguebit.org>
Tested-by: Ruikai Peng <ruikai@pwno.io>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
fs/smb/server/transport_rdma.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)

--- a/fs/smb/server/transport_rdma.c
+++ b/fs/smb/server/transport_rdma.c
@@ -1473,15 +1473,21 @@ static int smb_direct_post_send_data(str
if (ret)
goto err;

+ /*
+ * From here msg is moved to send_ctx
+ * and we should not free it explicitly.
+ */
+
if (send_ctx == &_send_ctx) {
ret = smb_direct_flush_send_list(sc, send_ctx, true);
if (ret)
- goto err;
+ goto flush_failed;
}

return 0;
err:
smb_direct_free_sendmsg(sc, msg);
+flush_failed:
header_failed:
atomic_inc(&sc->send_io.credits.count);