From patchwork Fri Feb 21 07:37:32 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 11395815 X-Patchwork-Delegate: herbert@gondor.apana.org.au Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id F0374924 for ; Fri, 21 Feb 2020 08:47:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CF7382465D for ; Fri, 21 Feb 2020 08:47:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1582274842; bh=PBddpNB+DNMdnowJ6YaKlTaS4CE/MvUsfaf/iV7W3yM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=IQu/NksOBYEjbibMm/GaN3kq0N9BL1SttnaF6thd88z2p5hzN+wQecArFZjcf88rk DXViqTmo6EbHgXoVgUxtjE/9NQ5GJBXF+JXsqRWquo6cpny36KnjMYkpbUv8rdnSN2 MZVMxFkPgeKaSHulDpLGsiOeDn7ESaEEylctiBOw= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728736AbgBUIrS (ORCPT ); Fri, 21 Feb 2020 03:47:18 -0500 Received: from mail.kernel.org ([198.145.29.99]:45108 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728638AbgBUHsy (ORCPT ); Fri, 21 Feb 2020 02:48:54 -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 7E619208C4; Fri, 21 Feb 2020 07:48:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1582271333; bh=PBddpNB+DNMdnowJ6YaKlTaS4CE/MvUsfaf/iV7W3yM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=VIoG48wgvKE6lJDh/9VbAxY47KqYvYtz6rjWBWGzchlfdXyXPS3hsvlG3xLowj0Q7 vkq4VAOaTC5WAtIPuImiHZE/IxrrXjw2mtVlisTDmb4ILtYjQFU8yPfRZKfheSl51A EtYaVEf+M/XrHR8BfeqZULB82V5q81mqwE8FmTQI= 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, Sasha Levin Subject: [PATCH 5.5 127/399] padata: always acquire cpu_hotplug_lock before pinst->lock Date: Fri, 21 Feb 2020 08:37:32 +0100 Message-Id: <20200221072414.822394328@linuxfoundation.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200221072402.315346745@linuxfoundation.org> References: <20200221072402.315346745@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 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; }