From d1aad52cf8b3f95dfe9b5b64da66343306ddf73b Mon Sep 17 00:00:00 2001 From: Jeffy Chen Date: Fri, 6 Oct 2017 17:45:28 +0300 Subject: [PATCH] xhci: Cleanup current_cmd in xhci_cleanup_command_queue() 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") Cc: # v4.12+ Signed-off-by: Jeffy Chen Signed-off-by: Mathias Nyman Signed-off-by: Greg Kroah-Hartman --- drivers/usb/host/xhci-ring.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c index a944365..48ae15af 100644 --- 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_cmd(struct xhci_command *cmd, u32 status) 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); } -- 2.7.4