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=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 BE285C2BB1D for ; Fri, 10 Apr 2020 03:54:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8C5D820936 for ; Fri, 10 Apr 2020 03:54:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1586490891; bh=i4Ubgx2oHuF1MCV7P/oM4IGjdCeU53Aw8AY1hqvYb3w=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=QAf5Q2/E8FCN/P7XzR6PMXBT6KxXKyXGJRaaqwIbAMV6AxFfU+WSf1D2U56V9Enp+ O57cS3qxchgDSwZSIBhHY6iXNey5U4L1Ar8nRkTf7Th7KC3KTM8fMxflYxbCjQjSTm yu4c6DFnwf7W1aZuqj32JcgvGqvKB48zMBsHCf6Y= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728253AbgDJDyl (ORCPT ); Thu, 9 Apr 2020 23:54:41 -0400 Received: from mail.kernel.org ([198.145.29.99]:34846 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728854AbgDJDuV (ORCPT ); Thu, 9 Apr 2020 23:50:21 -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 9866B21841; Fri, 10 Apr 2020 03:50:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1586490621; bh=i4Ubgx2oHuF1MCV7P/oM4IGjdCeU53Aw8AY1hqvYb3w=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=KSuiAlh2QFf03B/ZXAduKCxDIOoZrF0BD0UjY3xF6eWbARE509td9JfrEo25D9c9A K08ZRdA6wwJVo/w4pd+xqKQxnvicg3lMZTc+9FleO4zU9dyMWVH0qj+GdWKY7bVZwS Y63dhfX/y2g41UJMFaSmQXEWt+Zy+C5hCm5gmvK0= 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 4.19 13/32] PCI/switchtec: Fix init_completion race condition with poll_wait() Date: Thu, 9 Apr 2020 23:49:46 -0400 Message-Id: <20200410035005.9371-13-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200410035005.9371-1-sashal@kernel.org> References: <20200410035005.9371-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@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 43431816412c1..291c0074ad6f4 100644 --- a/drivers/pci/switch/switchtec.c +++ b/drivers/pci/switch/switchtec.c @@ -147,7 +147,7 @@ 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