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 8F8B9C352BE for ; Thu, 16 Apr 2020 15:25:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6C6D7214D8 for ; Thu, 16 Apr 2020 15:25:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1587050710; bh=lb20TAWB1L8o9R9POCRdfn3ZTAVt4zIsBHpavNxlDo0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=giXCg9EqkOjwE+A29HHor2BxbQVFJL85cEFa3ccuhp3onxfGcO3e92RmMiDAe8VaQ ywdY5BuwaoWJCqDrtPLoxX/x0AQcAZ9RmL8KflXT/Rhb0S4g3g2DD+RtxPthEtgLSj w+/A1hVbA+7Rwp3jljLrRE7leaUIVSLDzH1rh0Y8= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2504082AbgDPPZF (ORCPT ); Thu, 16 Apr 2020 11:25:05 -0400 Received: from mail.kernel.org ([198.145.29.99]:58114 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732331AbgDPNor (ORCPT ); Thu, 16 Apr 2020 09:44:47 -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 D691F208E4; Thu, 16 Apr 2020 13:44:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1587044686; bh=lb20TAWB1L8o9R9POCRdfn3ZTAVt4zIsBHpavNxlDo0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=hVzcfInvWxCscX6EGtOweKN3Y12I2CPaDdh5omjjjuDqiAx8kpRA8y47iDDtltpmV bXv/PufLWVVkEGrPBebHGSMB9fu7naSWDFZ58gqNt7UdwNZkWR4qagOpBZTNMzyU2J zrGVjBFnvbAhQFAwuD2dNpRQJo0gXeH6eeDEFquY= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Junyong Sun , Luis Chamberlain , Sasha Levin Subject: [PATCH 5.4 061/232] firmware: fix a double abort case with fw_load_sysfs_fallback Date: Thu, 16 Apr 2020 15:22:35 +0200 Message-Id: <20200416131323.089997778@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: Junyong Sun [ Upstream commit bcfbd3523f3c6eea51a74d217a8ebc5463bcb7f4 ] fw_sysfs_wait_timeout may return err with -ENOENT at fw_load_sysfs_fallback and firmware is already in abort status, no need to abort again, so skip it. This issue is caused by concurrent situation like below: when thread 1# wait firmware loading, thread 2# may write -1 to abort loading and wakeup thread 1# before it timeout. so wait_for_completion_killable_timeout of thread 1# would return remaining time which is != 0 with fw_st->status FW_STATUS_ABORTED.And the results would be converted into err -ENOENT in __fw_state_wait_common and transfered to fw_load_sysfs_fallback in thread 1#. The -ENOENT means firmware status is already at ABORTED, so fw_load_sysfs_fallback no need to get mutex to abort again. ----------------------------- thread 1#,wait for loading fw_load_sysfs_fallback ->fw_sysfs_wait_timeout ->__fw_state_wait_common ->wait_for_completion_killable_timeout in __fw_state_wait_common, ... 93 ret = wait_for_completion_killable_timeout(&fw_st->completion, timeout); 94 if (ret != 0 && fw_st->status == FW_STATUS_ABORTED) 95 return -ENOENT; 96 if (!ret) 97 return -ETIMEDOUT; 98 99 return ret < 0 ? ret : 0; ----------------------------- thread 2#, write -1 to abort loading firmware_loading_store ->fw_load_abort ->__fw_load_abort ->fw_state_aborted ->__fw_state_set ->complete_all in __fw_state_set, ... 111 if (status == FW_STATUS_DONE || status == FW_STATUS_ABORTED) 112 complete_all(&fw_st->completion); ------------------------------------------- BTW,the double abort issue would not cause kernel panic or create an issue, but slow down it sometimes.The change is just a minor optimization. Signed-off-by: Junyong Sun Acked-by: Luis Chamberlain Link: https://lore.kernel.org/r/1583202968-28792-1-git-send-email-sunjunyong@xiaomi.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin --- drivers/base/firmware_loader/fallback.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/base/firmware_loader/fallback.c b/drivers/base/firmware_loader/fallback.c index 62ee90b4db56e..70efbb22dfc30 100644 --- a/drivers/base/firmware_loader/fallback.c +++ b/drivers/base/firmware_loader/fallback.c @@ -525,7 +525,7 @@ static int fw_load_sysfs_fallback(struct fw_sysfs *fw_sysfs, } retval = fw_sysfs_wait_timeout(fw_priv, timeout); - if (retval < 0) { + if (retval < 0 && retval != -ENOENT) { mutex_lock(&fw_lock); fw_load_abort(fw_sysfs); mutex_unlock(&fw_lock); -- 2.20.1