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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,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 50E5FC2BB1D for ; Fri, 10 Apr 2020 03:52:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 11CAE20936 for ; Fri, 10 Apr 2020 03:52:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1586490773; bh=vYw31K3dfJsinyVeUtCj5HraLL20BgC3xRu/iOIZ+8k=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=COJwo6eeUhrL5iJIEIFUkYRtS8+YKQla5IHvMmxbK4Fh/8jJZ029kHS1HebionbGA n21YydotBBf/0aTbEAQTXGGVSvbR3kQy1ImKxznS/bbM1SCIBsJ3hFm5jTvXYJ0lGo 4nyA+Keln6XqN7N4pmeLRAkhDyiAu3V8H/9rExNM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729071AbgDJDvE (ORCPT ); Thu, 9 Apr 2020 23:51:04 -0400 Received: from mail.kernel.org ([198.145.29.99]:35860 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728381AbgDJDuz (ORCPT ); Thu, 9 Apr 2020 23:50:55 -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 CA215206C0; Fri, 10 Apr 2020 03:50:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1586490655; bh=vYw31K3dfJsinyVeUtCj5HraLL20BgC3xRu/iOIZ+8k=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=HdYiuID3Wo4Z2wgutxZxXgSXsgj2K5MugjBiGegNKVpJ9ybhAcmWrhec1KjXQ7uRB HVEgM8BNok+vR1WL+6rzCW/DK3IKVeKHdw9dws5tJO4zlhBu1DCVkuqsw/Lvbcbg7s 0x25kLa3jN1JsXFl/O+5qeFHETgAF8DzOitpF2EE= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Logan Gunthorpe , Sebastian Andrzej Siewior , Thomas Gleixner , Peter Zijlstra , Bjorn Helgaas , Sasha Levin , linux-pci@vger.kernel.org Subject: [PATCH AUTOSEL 4.14 09/22] PCI/switchtec: Fix init_completion race condition with poll_wait() Date: Thu, 9 Apr 2020 23:50:31 -0400 Message-Id: <20200410035044.9698-9-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200410035044.9698-1-sashal@kernel.org> References: <20200410035044.9698-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review 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: Logan Gunthorpe [ Upstream commit efbdc769601f4d50018bf7ca50fc9f7c67392ece ] The call to init_completion() in mrpc_queue_cmd() can theoretically race with the call to poll_wait() in switchtec_dev_poll(). poll() write() switchtec_dev_poll() switchtec_dev_write() poll_wait(&s->comp.wait); mrpc_queue_cmd() init_completion(&s->comp) init_waitqueue_head(&s->comp.wait) To my knowledge, no one has hit this bug. Fix this by using reinit_completion() instead of init_completion() in mrpc_queue_cmd(). Fixes: 080b47def5e5 ("MicroSemi Switchtec management interface driver") Reported-by: Sebastian Andrzej Siewior Signed-off-by: Logan Gunthorpe Signed-off-by: Thomas Gleixner Signed-off-by: Peter Zijlstra (Intel) Acked-by: Bjorn Helgaas Link: https://lkml.kernel.org/r/20200313183608.2646-1-logang@deltatee.com Signed-off-by: Sasha Levin --- drivers/pci/switch/switchtec.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/pci/switch/switchtec.c b/drivers/pci/switch/switchtec.c index bf229b442e723..6ef0d4b756f09 100644 --- a/drivers/pci/switch/switchtec.c +++ b/drivers/pci/switch/switchtec.c @@ -412,7 +412,7 @@ static int mrpc_queue_cmd(struct switchtec_user *stuser) kref_get(&stuser->kref); stuser->read_len = sizeof(stuser->data); stuser_set_state(stuser, MRPC_QUEUED); - init_completion(&stuser->comp); + reinit_completion(&stuser->comp); list_add_tail(&stuser->list, &stdev->mrpc_queue); mrpc_cmd_submit(stdev); -- 2.20.1