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=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,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 2F419C2BB55 for ; Thu, 16 Apr 2020 15:24:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 01D6A214D8 for ; Thu, 16 Apr 2020 15:24:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1587050699; bh=qmbLUSU/w7JaoSjE/dGj7Mwn2TrAusEL8vM6d4qoZQ0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=VaQRSNTseBcVyYQNus8lXHW10iVd9AAmVOTMzHnwpII0CibzPrKluUeKEOew05s3v q8eKeSgR9iow0uxdB74HrOEGfRKtFaLZw+/VXXaqvIE5vRyh9jYdwY9rCAzZDo8up9 NQlz1TRNKw+ByGDQM2i5rKNBJRV9ZIeUrQxqKMYM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2410208AbgDPPY5 (ORCPT ); Thu, 16 Apr 2020 11:24:57 -0400 Received: from mail.kernel.org ([198.145.29.99]:58194 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2392278AbgDPNoy (ORCPT ); Thu, 16 Apr 2020 09:44:54 -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 DE6FE21974; Thu, 16 Apr 2020 13:44:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1587044691; bh=qmbLUSU/w7JaoSjE/dGj7Mwn2TrAusEL8vM6d4qoZQ0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=IFcJ6nHxetEBgwyhnvrfJyjdPcsxun+u/phkkIpMs9rBotttWcVgQqPNtFI+sjsbB ivjvVffSDS/L10ZaHyMSeSiSQl+fLaE59y5lSDj1pMtroPO9fi3p88hnIgXnMzR19R nyPgTOak1u2UBBbMoRB8zXeBKhM8DcayEa7eHpU8= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Sebastian Andrzej Siewior , Logan Gunthorpe , Thomas Gleixner , "Peter Zijlstra (Intel)" , Bjorn Helgaas , Sasha Levin Subject: [PATCH 5.4 045/232] PCI/switchtec: Fix init_completion race condition with poll_wait() Date: Thu, 16 Apr 2020 15:22:19 +0200 Message-Id: <20200416131321.434601836@linuxfoundation.org> X-Mailer: git-send-email 2.26.1 In-Reply-To: <20200416131316.640996080@linuxfoundation.org> References: <20200416131316.640996080@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 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 cc43c855452f7..2c9c3061894b2 100644 --- a/drivers/pci/switch/switchtec.c +++ b/drivers/pci/switch/switchtec.c @@ -175,7 +175,7 @@ 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