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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,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 2B6B2C2D0D1 for ; Thu, 19 Dec 2019 19:09:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 014C8222C2 for ; Thu, 19 Dec 2019 19:09:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1576782557; bh=uQUVYng6M2m7kzxbBQV0vOzdqoLKSFhgyXgpvSS2DUA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=al0xaaxT0UFHP4IGrchsNKPQ3dqj6TqswcWAl0uL1IT3+TFqc54GJ73FGuZ/p6cN1 C2CxYru5engrO81KCERcf6jbVe+/tI4csCzprDS7X9aSDKaQe/AIBJYwkGfxlfqBWj k7CtejKKR7qTelRTyPFhFe60TyQvT+4krCeTVNek= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728374AbfLSTJP (ORCPT ); Thu, 19 Dec 2019 14:09:15 -0500 Received: from mail.kernel.org ([198.145.29.99]:59720 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728437AbfLSSkv (ORCPT ); Thu, 19 Dec 2019 13:40:51 -0500 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 7E82F24672; Thu, 19 Dec 2019 18:40:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1576780851; bh=uQUVYng6M2m7kzxbBQV0vOzdqoLKSFhgyXgpvSS2DUA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Msc3qdehJy7u8Pc20PC+t76aHkFINb2bJMjfC4Zhj3vgrdO7FTuM+irdNHDgn7C36 JUlCAa33ZXFOkIlMoSTuWUfhCDiQwf4W4BZMEI/DVBiLOCG2N9GSyR876Ct1rmehvL zUme/ZBWLT1Du0JEeW23AtABN/6Kr9jY8nNS1AlU= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Prarit Bhargava , Konstantin Khorenko , Jessica Yu , Sasha Levin Subject: [PATCH 4.4 142/162] kernel/module.c: wakeup processes in module_wq on module unload Date: Thu, 19 Dec 2019 19:34:10 +0100 Message-Id: <20191219183216.407633843@linuxfoundation.org> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20191219183150.477687052@linuxfoundation.org> References: <20191219183150.477687052@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Konstantin Khorenko [ Upstream commit 5d603311615f612320bb77bd2a82553ef1ced5b7 ] Fix the race between load and unload a kernel module. sys_delete_module() try_stop_module() mod->state = _GOING add_unformed_module() old = find_module_all() (old->state == _GOING => wait_event_interruptible()) During pre-condition finished_loading() rets 0 schedule() (never gets waken up later) free_module() mod->state = _UNFORMED list_del_rcu(&mod->list) (dels mod from "modules" list) return The race above leads to modprobe hanging forever on loading a module. Error paths on loading module call wake_up_all(&module_wq) after freeing module, so let's do the same on straight module unload. Fixes: 6e6de3dee51a ("kernel/module.c: Only return -EEXIST for modules that have finished loading") Reviewed-by: Prarit Bhargava Signed-off-by: Konstantin Khorenko Signed-off-by: Jessica Yu Signed-off-by: Sasha Levin --- kernel/module.c | 2 ++ 1 file changed, 2 insertions(+) --- a/kernel/module.c +++ b/kernel/module.c @@ -1014,6 +1014,8 @@ SYSCALL_DEFINE2(delete_module, const cha strlcpy(last_unloaded_module, mod->name, sizeof(last_unloaded_module)); free_module(mod); + /* someone could wait for the module in add_unformed_module() */ + wake_up_all(&module_wq); return 0; out: mutex_unlock(&module_mutex);