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=-14.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 0DF08C43381 for ; Wed, 27 Mar 2019 18:18:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D54592177E for ; Wed, 27 Mar 2019 18:18:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1553710730; bh=TKkvdM3wjz8wa5jZlRk9rqtGhfEV+dYeNS8YZxQNC5o=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=FtvOKqvC4fpM7qlP50OiBp6f0XydeZO6AChrFWTsnFnm6cT9dGe/ZOzvy/RaKS0OF AYiSk+kG2Q6NoVNmf1qFsA769AiuXnlJHeWWDawhbfBS5GNAPRqNY5dtwwEbVLT5lU a+Ovn7/UAqKHYdPiqkA05xBdEHPLDNcHNky1EndQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390599AbfC0SSt (ORCPT ); Wed, 27 Mar 2019 14:18:49 -0400 Received: from mail.kernel.org ([198.145.29.99]:35810 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390585AbfC0SSp (ORCPT ); Wed, 27 Mar 2019 14:18:45 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 05D9920449; Wed, 27 Mar 2019 18:18:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1553710724; bh=TKkvdM3wjz8wa5jZlRk9rqtGhfEV+dYeNS8YZxQNC5o=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=EgOUUog4KJQ00I6UPH4EuHvlM2WxkTiVJNJoCpVJQfVWnukkbRfutbSvPblAlev+L U7L8ADA8dvfJw/iMt0ZhM5b3pBh9x+vxSS2/wB57oYDbeGB8+PjwQL5Uha0zqo1//g 7kliAZq5L+V87q6u4t6WHO4+WVUFAH8Ra0TdBhWI= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: John Stultz , Alan Stern , Felipe Balbi , Zeng Tao , Jack Pham , Thinh Nguyen , Chen Yu , Jerry Zhang , Lars-Peter Clausen , Vincent Pelletier , Andrzej Pietrasiewicz , Greg Kroah-Hartman , Linux USB List , Felipe Balbi , Sasha Levin Subject: [PATCH AUTOSEL 4.14 073/123] usb: f_fs: Avoid crash due to out-of-scope stack ptr access Date: Wed, 27 Mar 2019 14:15:37 -0400 Message-Id: <20190327181628.15899-73-sashal@kernel.org> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20190327181628.15899-1-sashal@kernel.org> References: <20190327181628.15899-1-sashal@kernel.org> MIME-Version: 1.0 X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: John Stultz [ Upstream commit 54f64d5c983f939901dacc8cfc0983727c5c742e ] Since the 5.0 merge window opened, I've been seeing frequent crashes on suspend and reboot with the trace: [ 36.911170] Unable to handle kernel paging request at virtual address ffffff801153d660 [ 36.912769] Unable to handle kernel paging request at virtual address ffffff800004b564 ... [ 36.950666] Call trace: [ 36.950670] queued_spin_lock_slowpath+0x1cc/0x2c8 [ 36.950681] _raw_spin_lock_irqsave+0x64/0x78 [ 36.950692] complete+0x28/0x70 [ 36.950703] ffs_epfile_io_complete+0x3c/0x50 [ 36.950713] usb_gadget_giveback_request+0x34/0x108 [ 36.950721] dwc3_gadget_giveback+0x50/0x68 [ 36.950723] dwc3_thread_interrupt+0x358/0x1488 [ 36.950731] irq_thread_fn+0x30/0x88 [ 36.950734] irq_thread+0x114/0x1b0 [ 36.950739] kthread+0x104/0x130 [ 36.950747] ret_from_fork+0x10/0x1c I isolated this down to in ffs_epfile_io(): https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/usb/gadget/function/f_fs.c#n1065 Where the completion done is setup on the stack: DECLARE_COMPLETION_ONSTACK(done); Then later we setup a request and queue it, and wait for it: if (unlikely(wait_for_completion_interruptible(&done))) { /* * To avoid race condition with ffs_epfile_io_complete, * dequeue the request first then check * status. usb_ep_dequeue API should guarantee no race * condition with req->complete callback. */ usb_ep_dequeue(ep->ep, req); interrupted = ep->status < 0; } The problem is, that we end up being interrupted, dequeue the request, and exit. But then the irq triggers and we try calling complete() on the context pointer which points to now random stack space, which results in the panic. Alan Stern pointed out there is a bug here, in that the snippet above "assumes that usb_ep_dequeue() waits until the request has been completed." And that: wait_for_completion(&done); Is needed right after the usb_ep_dequeue(). Thus this patch implements that change. With it I no longer see the crashes on suspend or reboot. This issue seems to have been uncovered by behavioral changes in the dwc3 driver in commit fec9095bdef4e ("usb: dwc3: gadget: remove wait_end_transfer"). Cc: Alan Stern Cc: Felipe Balbi Cc: Zeng Tao Cc: Jack Pham Cc: Thinh Nguyen Cc: Chen Yu Cc: Jerry Zhang Cc: Lars-Peter Clausen Cc: Vincent Pelletier Cc: Andrzej Pietrasiewicz Cc: Greg Kroah-Hartman Cc: Linux USB List Suggested-by: Alan Stern Signed-off-by: John Stultz Signed-off-by: Felipe Balbi Signed-off-by: Sasha Levin --- drivers/usb/gadget/function/f_fs.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/usb/gadget/function/f_fs.c b/drivers/usb/gadget/function/f_fs.c index 52e6897fa35a..79900c0b4f3a 100644 --- a/drivers/usb/gadget/function/f_fs.c +++ b/drivers/usb/gadget/function/f_fs.c @@ -1009,6 +1009,7 @@ static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data) * condition with req->complete callback. */ usb_ep_dequeue(ep->ep, req); + wait_for_completion(&done); interrupted = ep->status < 0; } -- 2.19.1