Re: [PATCH 1/2] usb: host: xhci: Fix possible wild pointer when handling abort command

From: Mathias Nyman
Date: Mon Dec 05 2016 - 09:07:38 EST


On 05.12.2016 09:51, Baolin Wang wrote:
When current command was supposed to be aborted, host will free the command
in handle_cmd_completion() function. But it might be still referenced by
xhci->current_cmd, which need to set NULL.

Signed-off-by: Baolin Wang <baolin.wang@xxxxxxxxxx>
---
This patch is based on Lu Baolu's new fix patch:
usb: xhci: fix possible wild pointer
https://www.spinics.net/lists/linux-usb/msg150219.html
---
drivers/usb/host/xhci-ring.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index 62dd1c7..9965a4c 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -1362,8 +1362,11 @@ static void handle_cmd_completion(struct xhci_hcd *xhci,
*/
if (cmd_comp_code == COMP_CMD_ABORT) {
xhci->cmd_ring_state = CMD_RING_STATE_STOPPED;
- if (cmd->status == COMP_CMD_ABORT)
+ if (cmd->status == COMP_CMD_ABORT) {
+ if (xhci->current_cmd == cmd)
+ xhci->current_cmd = NULL;
goto event_handled;
+ }
}

cmd_type = TRB_FIELD_TO_TYPE(le32_to_cpu(cmd_trb->generic.field[3]));


True, thanks

-Mathias