4.13-stable review patch. If anyone has any objections, please let me know.
------------------
From: Jeffy Chen <jeffy.chen@xxxxxxxxxxxxxx>
commit d1aad52cf8b3f95dfe9b5b64da66343306ddf73b upstream.
KASAN reported use-after-free bug when xhci host controller died:
[ 176.952537] BUG: KASAN: use-after-free in xhci_handle_command_timeout+0x68/0x224
[ 176.960846] Write of size 4 at addr ffffffc0cbb01608 by task kworker/3:3/1680
...
[ 177.180644] Freed by task 0:
[ 177.183882] kasan_slab_free+0x90/0x15c
[ 177.188194] kfree+0x114/0x28c
[ 177.191630] xhci_cleanup_command_queue+0xc8/0xf8
[ 177.196916] xhci_hc_died+0x84/0x358
Problem here is that when the cmd_timer fired, it would try to access
current_cmd while the command queue is already freed by xhci_hc_died().
Cleanup current_cmd in xhci_cleanup_command_queue() to avoid that.
Fixes: d9f11ba9f107 ("xhci: Rework how we handle unresponsive or hoptlug removed hosts")
Signed-off-by: Jeffy Chen <jeffy.chen@xxxxxxxxxxxxxx>
Signed-off-by: Mathias Nyman <mathias.nyman@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/usb/host/xhci-ring.c | 1 +
1 file changed, 1 insertion(+)
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -1309,6 +1309,7 @@ static void xhci_complete_del_and_free_c
void xhci_cleanup_command_queue(struct xhci_hcd *xhci)
{
struct xhci_command *cur_cmd, *tmp_cmd;
+ xhci->current_cmd = NULL;
list_for_each_entry_safe(cur_cmd, tmp_cmd, &xhci->cmd_list, cmd_list)
xhci_complete_del_and_free_cmd(cur_cmd, COMP_COMMAND_ABORTED);
}