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=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 8F445C3F2DB for ; Tue, 3 Mar 2020 18:09:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6A05F208C3 for ; Tue, 3 Mar 2020 18:09:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1583258979; bh=nekBzOBwg7MSUfjgB1WlnAg8CmwfUXUhpErEo3+ryck=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=S2F4vhEHGG/U7pQp8DRCzhhlN4kaISXUqfiIl4qINYy5vNuyKHCHO9dUPICcJKlBK uRCztyRyfLyUoqTUW/+juZP3aEIvhMgP/+CUtSXzvrcPXi0dcnHRJUeSL30OLOGVli dJ3UKhoMGxzMfJCkER2xiNbhYcqsrN9TJGPTee/0= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732093AbgCCRwD (ORCPT ); Tue, 3 Mar 2020 12:52:03 -0500 Received: from mail.kernel.org ([198.145.29.99]:60300 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732089AbgCCRwD (ORCPT ); Tue, 3 Mar 2020 12:52:03 -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 0B0C62146E; Tue, 3 Mar 2020 17:52:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1583257922; bh=nekBzOBwg7MSUfjgB1WlnAg8CmwfUXUhpErEo3+ryck=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ikp/tQyoM4kVk08ULZcNSKyJkkQ2OSbuF6m2/LnjUj04SBJlUFsUjh5UgRhTLUhDZ tUuBp/P/dz/SyqMoH2DZhoaCfQOxmyYMFZgw6U91V8+b/shuyC5bn8O4V/ZLibEGGZ GTlDDLeeRukFwXNq81nZq2ju+cN4EwXhCTdSdDqQ= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Daniel Jordan , Eric Biggers , Herbert Xu , Steffen Klassert , linux-crypto@vger.kernel.org Subject: [PATCH 5.5 169/176] padata: always acquire cpu_hotplug_lock before pinst->lock Date: Tue, 3 Mar 2020 18:43:53 +0100 Message-Id: <20200303174323.557292375@linuxfoundation.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200303174304.593872177@linuxfoundation.org> References: <20200303174304.593872177@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: Daniel Jordan commit 38228e8848cd7dd86ccb90406af32de0cad24be3 upstream. 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: Greg Kroah-Hartman --- kernel/padata.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/kernel/padata.c +++ b/kernel/padata.c @@ -643,8 +643,8 @@ int padata_set_cpumask(struct padata_ins 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_ins err = __padata_set_cpumasks(pinst, parallel_mask, serial_mask); out: - put_online_cpus(); mutex_unlock(&pinst->lock); + put_online_cpus(); return err; }