From patchwork Fri May 8 12:29:58 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 226298 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,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT autolearn=unavailable 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 EA80CC47254 for ; Fri, 8 May 2020 12:37:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CA6E321BE5 for ; Fri, 8 May 2020 12:37:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1588941421; bh=fDxB7yOTpGNNY3i43zVtWuGlUS+QbkbR0NmagnPSfpQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=f6/2IPACzljRjfLqKiE8qt7izPEYcbJFTxng9QKiI4LJmfQvAInEGrXTu5iX+TmCe iZmexdVdhf+znjE3PGzFQk2VQ69ce0jot/VnS++BDvZVcDwPotOwUNIbau10LEQSYu hy1wDLzQeg9whD6MGliXa1hLxp67bklp+xLbMCac= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727937AbgEHMgz (ORCPT ); Fri, 8 May 2020 08:36:55 -0400 Received: from mail.kernel.org ([198.145.29.99]:50774 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727904AbgEHMgz (ORCPT ); Fri, 8 May 2020 08:36:55 -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 140D521473; Fri, 8 May 2020 12:36:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1588941414; bh=fDxB7yOTpGNNY3i43zVtWuGlUS+QbkbR0NmagnPSfpQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=hcXoU4UkWHl0fzo4sr/IJvDYObs/OXWrMD+YK9teTdGJRNGChBfCgPFlKCQiRK/ff v6S4tcr/BUbkEIrmXYkrSkc0PPpvpTXc6eHGOSlJpPAwfNERdtWvk390IG6zWWecue bVhFOPO+UzZlw1Pd2HEzOsbenERSHnjsGC9tNGvg= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Iago Abal , Felipe Balbi Subject: [PATCH 4.4 007/312] usb: gadget: pch_udc: reorder spin_[un]lock to avoid deadlock Date: Fri, 8 May 2020 14:29:58 +0200 Message-Id: <20200508123125.033701501@linuxfoundation.org> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200508123124.574959822@linuxfoundation.org> References: <20200508123124.574959822@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Iago Abal commit 1d23d16a88e6c8143b07339435ba061b131ebb8c upstream. The above commit reordered spin_lock/unlock and now `&dev->lock' is acquired (rather than released) before calling `dev->driver->disconnect', `dev->driver->setup', `dev->driver->suspend', `usb_gadget_giveback_request', and `usb_gadget_udc_reset'. But this *may* not be the right way to fix the problem pointed by d3cb25a12138. Note that the other usb/gadget/udc drivers do release the lock before calling these functions. There are also inconsistencies within pch_udc.c, where `dev->driver->disconnect' is called while holding `&dev->lock' in lines 613 and 1184, but not in line 2739. Finally, commit d3cb25a12138 may have introduced several potential deadlocks. For instance, EBA (https://github.com/models-team/eba) reports: Double lock in drivers/usb/gadget/udc/pch_udc.c first at 2791: spin_lock(& dev->lock); [pch_udc_isr] second at 2694: spin_lock(& dev->lock); [pch_udc_svc_cfg_interrupt] after calling from 2793: pch_udc_dev_isr(dev, dev_intr); after calling from 2724: pch_udc_svc_cfg_interrupt(dev); Similarly, other potential deadlocks are 2791 -> 2793 -> 2721 -> 2657; and 2791 -> 2793 -> 2711 -> 2573 -> 1499 -> 1480. Fixes: d3cb25a12138 ("usb: gadget: udc: fix spin_lock in pch_udc") Signed-off-by: Iago Abal Signed-off-by: Felipe Balbi Signed-off-by: Greg Kroah-Hartman --- drivers/usb/gadget/udc/pch_udc.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) --- a/drivers/usb/gadget/udc/pch_udc.c +++ b/drivers/usb/gadget/udc/pch_udc.c @@ -1488,11 +1488,11 @@ static void complete_req(struct pch_udc_ req->dma_mapped = 0; } ep->halted = 1; - spin_lock(&dev->lock); + spin_unlock(&dev->lock); if (!ep->in) pch_udc_ep_clear_rrdy(ep); usb_gadget_giveback_request(&ep->ep, &req->req); - spin_unlock(&dev->lock); + spin_lock(&dev->lock); ep->halted = halted; } @@ -2583,9 +2583,9 @@ static void pch_udc_svc_ur_interrupt(str empty_req_queue(ep); } if (dev->driver) { - spin_lock(&dev->lock); - usb_gadget_udc_reset(&dev->gadget, dev->driver); spin_unlock(&dev->lock); + usb_gadget_udc_reset(&dev->gadget, dev->driver); + spin_lock(&dev->lock); } } @@ -2664,9 +2664,9 @@ static void pch_udc_svc_intf_interrupt(s dev->ep[i].halted = 0; } dev->stall = 0; - spin_lock(&dev->lock); - dev->driver->setup(&dev->gadget, &dev->setup_data); spin_unlock(&dev->lock); + dev->driver->setup(&dev->gadget, &dev->setup_data); + spin_lock(&dev->lock); } /** @@ -2701,9 +2701,9 @@ static void pch_udc_svc_cfg_interrupt(st dev->stall = 0; /* call gadget zero with setup data received */ - spin_lock(&dev->lock); - dev->driver->setup(&dev->gadget, &dev->setup_data); spin_unlock(&dev->lock); + dev->driver->setup(&dev->gadget, &dev->setup_data); + spin_lock(&dev->lock); } /**