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,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 6032FC3B1A6 for ; Fri, 14 Feb 2020 17:36:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3D3432082F for ; Fri, 14 Feb 2020 17:36:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1581701790; bh=PBddpNB+DNMdnowJ6YaKlTaS4CE/MvUsfaf/iV7W3yM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=RggNGXN6CwREX5u2d18xcsN1rVN8P5q0aFRABEokd5zePdQ4QGf+BfW9/6vIAvDKQ qdhyHP9OLleR1kuQt/ZH9kGUoAqplhC8rW5HkWPbciCJWYrxMSi+Di3Z8vpyzfrNoj zyuH36Pe83O+bOY7Mnj/hfE08K4g8E92iEFcFH1k= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390189AbgBNQFc (ORCPT ); Fri, 14 Feb 2020 11:05:32 -0500 Received: from mail.kernel.org ([198.145.29.99]:55386 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389414AbgBNQFc (ORCPT ); Fri, 14 Feb 2020 11:05:32 -0500 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 719042467D; Fri, 14 Feb 2020 16:05:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1581696331; bh=PBddpNB+DNMdnowJ6YaKlTaS4CE/MvUsfaf/iV7W3yM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=rHIOTuohVa4meAjkRZla0MrlRCOJYuV4NjqBsxQVlGDZK4zcjDsXUWmdk2o39TdHj 4j0rkb3VLM4Nc2zpNGbZLNbTYp7ijlKDXaM+xiFC7D49aGsGg2yt6r0ZFBkZ7pwW3M w/TdtREp16AlMEJWW/7FomB+2hwO1lStXyLPJsVQ= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Daniel Jordan , Eric Biggers , Herbert Xu , Steffen Klassert , linux-crypto@vger.kernel.org, Sasha Levin Subject: [PATCH AUTOSEL 5.4 169/459] padata: always acquire cpu_hotplug_lock before pinst->lock Date: Fri, 14 Feb 2020 10:56:59 -0500 Message-Id: <20200214160149.11681-169-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200214160149.11681-1-sashal@kernel.org> References: <20200214160149.11681-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-crypto-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-crypto@vger.kernel.org From: Daniel Jordan [ Upstream commit 38228e8848cd7dd86ccb90406af32de0cad24be3 ] lockdep complains when padata's paths to update cpumasks via CPU hotplug and sysfs are both taken: # echo 0 > /sys/devices/system/cpu/cpu1/online # echo ff > /sys/kernel/pcrypt/pencrypt/parallel_cpumask ====================================================== WARNING: possible circular locking dependency detected 5.4.0-rc8-padata-cpuhp-v3+ #1 Not tainted ------------------------------------------------------ bash/205 is trying to acquire lock: ffffffff8286bcd0 (cpu_hotplug_lock.rw_sem){++++}, at: padata_set_cpumask+0x2b/0x120 but task is already holding lock: ffff8880001abfa0 (&pinst->lock){+.+.}, at: padata_set_cpumask+0x26/0x120 which lock already depends on the new lock. padata doesn't take cpu_hotplug_lock and pinst->lock in a consistent order. Which should be first? CPU hotplug calls into padata with cpu_hotplug_lock already held, so it should have priority. Fixes: 6751fb3c0e0c ("padata: Use get_online_cpus/put_online_cpus") Signed-off-by: Daniel Jordan Cc: Eric Biggers Cc: Herbert Xu Cc: Steffen Klassert Cc: linux-crypto@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Herbert Xu Signed-off-by: Sasha Levin --- kernel/padata.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/padata.c b/kernel/padata.c index fda7a7039422d..fdbbe96547713 100644 --- a/kernel/padata.c +++ b/kernel/padata.c @@ -643,8 +643,8 @@ int padata_set_cpumask(struct padata_instance *pinst, int cpumask_type, struct cpumask *serial_mask, *parallel_mask; int err = -EINVAL; - mutex_lock(&pinst->lock); get_online_cpus(); + mutex_lock(&pinst->lock); switch (cpumask_type) { case PADATA_CPU_PARALLEL: @@ -662,8 +662,8 @@ int padata_set_cpumask(struct padata_instance *pinst, int cpumask_type, err = __padata_set_cpumasks(pinst, parallel_mask, serial_mask); out: - put_online_cpus(); mutex_unlock(&pinst->lock); + put_online_cpus(); return err; } -- 2.20.1