From d1aad52cf8b3f95dfe9b5b64da66343306ddf73b Mon Sep 17 00:00:00 2001
From: Jeffy Chen <jeffy.chen@rock-chips.com>
Date: Fri, 6 Oct 2017 17:45:28 +0300
Subject: [PATCH] xhci: Cleanup current_cmd in xhci_cleanup_command_queue()
Git-commit: d1aad52cf8b3f95dfe9b5b64da66343306ddf73b
Patch-mainline: v4.14-rc6
References: bsc#1085536
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: <stable@vger.kernel.org> # v4.12+
Signed-off-by: Jeffy Chen <jeffy.chen@rock-chips.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Oliver Neukum <oneukum@suse.com>
---
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 a9443651ce0f..48ae15afa59e 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);
}
--
2.13.6