From: Dan Carpenter dan.carpenter@oracle.com
commit 08b0c891605acf727e43e3e03a25857d3e789b61 upstream.
We recently added a kfree() after the end of the loop:
if (retries == RETRIES) { kfree(reply); return -EINVAL; }
There are two problems. First the test is wrong and because retries equals RETRIES if we succeed on the last iteration through the loop. Second if we fail on the last iteration through the loop then the kfree is a double free.
When you're reading this code, please note the break statement at the end of the while loop. This patch changes the loop so that if it's not successful then "reply" is NULL and we can test for that afterward.
Cc: stable@vger.kernel.org Fixes: 6b7c3b86f0b6 ("drm/vmwgfx: fix memory leak when too many retries have occurred") Signed-off-by: Dan Carpenter dan.carpenter@oracle.com Reviewed-by: Thomas Hellstrom thellstrom@vmware.com Signed-off-by: Thomas Hellstrom thellstrom@vmware.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/gpu/drm/vmwgfx/vmwgfx_msg.c | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-)
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_msg.c +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_msg.c @@ -264,7 +264,7 @@ static int vmw_recv_msg(struct rpc_chann
if ((HIGH_WORD(ebx) & MESSAGE_STATUS_SUCCESS) == 0) { kfree(reply); - + reply = NULL; if ((HIGH_WORD(ebx) & MESSAGE_STATUS_CPT) != 0) { /* A checkpoint occurred. Retry. */ continue; @@ -288,7 +288,7 @@ static int vmw_recv_msg(struct rpc_chann
if ((HIGH_WORD(ecx) & MESSAGE_STATUS_SUCCESS) == 0) { kfree(reply); - + reply = NULL; if ((HIGH_WORD(ecx) & MESSAGE_STATUS_CPT) != 0) { /* A checkpoint occurred. Retry. */ continue; @@ -300,10 +300,8 @@ static int vmw_recv_msg(struct rpc_chann break; }
- if (retries == RETRIES) { - kfree(reply); + if (!reply) return -EINVAL; - }
*msg_len = reply_len; *msg = reply;