Patch "xhci: init command timeout timer earlier to avoid deleting it uninitialized" has been added to the 4.1-stable tree

This is a note to let you know that I've just added the patch titled

xhci: init command timeout timer earlier to avoid deleting it uninitialized

to the 4.1-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
xhci-init-command-timeout-timer-earlier-to-avoid-deleting-it-uninitialized.patch
and it can be found in the queue-4.1 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Mathias Nyman <[email protected]>
Date: Mon, 21 Sep 2015 17:46:17 +0300
Subject: xhci: init command timeout timer earlier to avoid deleting it uninitialized

From: Mathias Nyman <[email protected]>

commit cc8e4fc0c3b5e8340bc8358990515d116a3c274c upstream.

Don't check if timer is running with a timer_pending() before deleting it with del_timer_sync(), this defies the whole point of the sync part and can cause a possible race.

Instead we just want to make sure the timer is initialized early enough before we have a chance to delete it.

---
 drivers/usb/host/xhci-mem.c |   11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

@@ -1792,8 +1792,7 @@ void xhci_mem_cleanup(struct xhci_hcd *x
 	int size;
 	int i, j, num_ports;
 
-	if (timer_pending(&xhci->cmd_timer))
-		del_timer_sync(&xhci->cmd_timer);
+	del_timer_sync(&xhci->cmd_timer);
 
 	/* Free the Event Ring Segment Table and the actual Event Ring */
 	size = sizeof(struct xhci_erst_entry)*(xhci->erst.num_entries);

@@ -2321,6 +2320,10 @@ int xhci_mem_init(struct xhci_hcd *xhci,
 
 	INIT_LIST_HEAD(&xhci->cmd_list);
 
+	/* init command timeout timer */
+	setup_timer(&xhci->cmd_timer, xhci_handle_command_timeout,
+		    (unsigned long)xhci);
+
 	page_size = readl(&xhci->op_regs->page_size);
 	xhci_dbg_trace(xhci, trace_xhci_dbg_init,
 			"Supported page size register = 0x%x", page_size);

@@ -2505,10 +2508,6 @@ int xhci_mem_init(struct xhci_hcd *xhci,
 			"Wrote ERST address to ir_set 0.");
 	xhci_print_ir_set(xhci, 0);
 
-	/* init command timeout timer */
-	setup_timer(&xhci->cmd_timer, xhci_handle_command_timeout,
-		    (unsigned long)xhci);
-
 	/*
 	 * XXX: Might need to set the Interrupter Moderation Register to
 	 * something other than the default (~1ms minimum between interrupts).

Patches currently in stable-queue which might be from [email protected] are

queue-4.1/usb-xhci-exit-early-in-xhci_setup_device-if-we-re-halted-or-dying.patch queue-4.1/xhci-give-command-abortion-one-more-chance-before-killing-xhci.patch queue-4.1/usb-xhci-clear-xhci_state_dying-on-start.patch queue-4.1/usb-xhci-add-support-for-urb_zero_packet-to-bulk-sg-transfers.patch queue-4.1/xhci-init-command-timeout-timer-earlier-to-avoid-deleting-it-uninitialized.patch queue-4.1/usb-xhci-lock-mutex-on-xhci_stop.patch queue-4.1/xhci-change-xhci-1.0-only-restrictions-to-support-xhci-1.1.patch