From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-11.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A6282C4360C for ; Fri, 4 Oct 2019 12:33:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 78D63222BE for ; Fri, 4 Oct 2019 12:33:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1570192406; bh=O+34Z433+qWIQOMJcdoi9SXO2QO8Jm8MPqsrVP9HkUE=; h=Subject:To:From:Date:List-ID:From; b=AVm7J5Wjyl6wX8gvNUyJtNUYUV2jbklyD4+/XYSrV2CZlBCeHdACnUuVaUcEy0MmN kj5KpeNPxnDYbY2WFxLLJ653h0snfSprxhR5VU0FWe3HzfKnBFe2ThQM2QLjQIw/Wc YnZlHDqlXZIvEgAfbRauuGZMfnbsBlJWbZwEjSd0= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730627AbfJDMd0 (ORCPT ); Fri, 4 Oct 2019 08:33:26 -0400 Received: from mail.kernel.org ([198.145.29.99]:53498 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726024AbfJDMdZ (ORCPT ); Fri, 4 Oct 2019 08:33:25 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 0737621D71; Fri, 4 Oct 2019 12:33:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1570192403; bh=O+34Z433+qWIQOMJcdoi9SXO2QO8Jm8MPqsrVP9HkUE=; h=Subject:To:From:Date:From; b=Jb6wu//omiouDcXNu6ChhU+5KuSsUxr1LY6ABpjzBRylzyXC+h4SUy15ZLotMApZ8 rlLucD4GXlV9FW18XyI95kDaRpITHJiGKQL4VTJhd2a88OYoj40iMhDYYAATTH2kTs dstZG4c/rqaXKO7VJDsjQ90wJAhtOxAnf3hmigYE= Subject: patch "xhci: Prevent deadlock when xhci adapter breaks during init" added to usb-linus To: William.Kuzeja@stratus.com, gregkh@linuxfoundation.org, mathias.nyman@linux.intel.com, stable@vger.kernel.org, torez@redhat.com, william.kuzeja@stratus.com From: Date: Fri, 04 Oct 2019 14:33:07 +0200 Message-ID: <157019238714363@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org This is a note to let you know that I've just added the patch titled xhci: Prevent deadlock when xhci adapter breaks during init to my usb git tree which can be found at git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git in the usb-linus branch. The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.) The patch will hopefully also be merged in Linus's tree for the next -rc kernel release. If you have any questions about this process, please let me know. >From 8de66b0e6a56ff10dd00d2b0f2ae52e300178587 Mon Sep 17 00:00:00 2001 From: Bill Kuzeja Date: Fri, 4 Oct 2019 14:59:31 +0300 Subject: xhci: Prevent deadlock when xhci adapter breaks during init The system can hit a deadlock if an xhci adapter breaks while initializing. The deadlock is between two threads: thread 1 is tearing down the adapter and is stuck in usb_unlocked_disable_lpm waiting to lock the hcd->handwidth_mutex. Thread 2 is holding this mutex (while still trying to add a usb device), but is stuck in xhci_endpoint_reset waiting for a stop or config command to complete. A reboot is required to resolve. It turns out when calling xhci_queue_stop_endpoint and xhci_queue_configure_endpoint in xhci_endpoint_reset, the return code is not checked for errors. If the timing is right and the adapter dies just before either of these commands get issued, we hang indefinitely waiting for a completion on a command that didn't get issued. This wasn't a problem before the following fix because we didn't send commands in xhci_endpoint_reset: commit f5249461b504 ("xhci: Clear the host side toggle manually when endpoint is soft reset") With the patch I am submitting, a duration test which breaks adapters during initialization (and which deadlocks with the standard kernel) runs without issue. Fixes: f5249461b504 ("xhci: Clear the host side toggle manually when endpoint is soft reset") Cc: # v4.17+ Cc: Torez Smith Signed-off-by: Bill Kuzeja Signed-off-by: Torez Smith Signed-off-by: Mathias Nyman Link: https://lore.kernel.org/r/1570190373-30684-7-git-send-email-mathias.nyman@linux.intel.com Signed-off-by: Greg Kroah-Hartman --- drivers/usb/host/xhci.c | 23 +++++++++++++++++++++-- 1 file changed, 21 insertions(+), 2 deletions(-) diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c index fe8f9ff58015..8c068d0cc7c1 100644 --- a/drivers/usb/host/xhci.c +++ b/drivers/usb/host/xhci.c @@ -3095,6 +3095,7 @@ static void xhci_endpoint_reset(struct usb_hcd *hcd, unsigned int ep_index; unsigned long flags; u32 ep_flag; + int err; xhci = hcd_to_xhci(hcd); if (!host_ep->hcpriv) @@ -3154,7 +3155,17 @@ static void xhci_endpoint_reset(struct usb_hcd *hcd, xhci_free_command(xhci, cfg_cmd); goto cleanup; } - xhci_queue_stop_endpoint(xhci, stop_cmd, udev->slot_id, ep_index, 0); + + err = xhci_queue_stop_endpoint(xhci, stop_cmd, udev->slot_id, + ep_index, 0); + if (err < 0) { + spin_unlock_irqrestore(&xhci->lock, flags); + xhci_free_command(xhci, cfg_cmd); + xhci_dbg(xhci, "%s: Failed to queue stop ep command, %d ", + __func__, err); + goto cleanup; + } + xhci_ring_cmd_db(xhci); spin_unlock_irqrestore(&xhci->lock, flags); @@ -3168,8 +3179,16 @@ static void xhci_endpoint_reset(struct usb_hcd *hcd, ctrl_ctx, ep_flag, ep_flag); xhci_endpoint_copy(xhci, cfg_cmd->in_ctx, vdev->out_ctx, ep_index); - xhci_queue_configure_endpoint(xhci, cfg_cmd, cfg_cmd->in_ctx->dma, + err = xhci_queue_configure_endpoint(xhci, cfg_cmd, cfg_cmd->in_ctx->dma, udev->slot_id, false); + if (err < 0) { + spin_unlock_irqrestore(&xhci->lock, flags); + xhci_free_command(xhci, cfg_cmd); + xhci_dbg(xhci, "%s: Failed to queue config ep command, %d ", + __func__, err); + goto cleanup; + } + xhci_ring_cmd_db(xhci); spin_unlock_irqrestore(&xhci->lock, flags); -- 2.23.0