From patchwork Tue Apr 7 10:22:17 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 11477859 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 6265892A for ; Tue, 7 Apr 2020 10:28:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 410092074F for ; Tue, 7 Apr 2020 10:28:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1586255298; bh=nekBzOBwg7MSUfjgB1WlnAg8CmwfUXUhpErEo3+ryck=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=P3pffRbPOe82fxm46AV3WLOWAl7ntemMsx5hZTIdv1PGeJGSwLPb8bzqSYqN3abm/ mon7+2Vnrva8+34lZj9ZQXSm6FRthkhE5oFIDTFVaBiGQLrjdeFIJzccX2mxpzZTks PunV6sGi+XcqhYiGJxZIEBd22xWK2Lalv2k28AAE= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728635AbgDGKZm (ORCPT ); Tue, 7 Apr 2020 06:25:42 -0400 Received: from mail.kernel.org ([198.145.29.99]:36348 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728992AbgDGKZk (ORCPT ); Tue, 7 Apr 2020 06:25:40 -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 214AB2078A; Tue, 7 Apr 2020 10:25:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1586255139; bh=nekBzOBwg7MSUfjgB1WlnAg8CmwfUXUhpErEo3+ryck=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Yc6fNzoWI3kHBDrte4ztLgPpcUjpQZYD6BgKlDxhcEywLOQZiNNDYxX2fl7BotNy2 rJtx92mQnTDJ8yG9edRJjUWdUFRDfMREZ7Je5UiDyeXPViWaPi2i9t7BWzitQqpPzk TscHrYgpkBRlcy1kGdU4+lUpBZqemTe164Ol8BAE= 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 46/46] padata: always acquire cpu_hotplug_lock before pinst->lock Date: Tue, 7 Apr 2020 12:22:17 +0200 Message-Id: <20200407101504.206060352@linuxfoundation.org> X-Mailer: git-send-email 2.26.0 In-Reply-To: <20200407101459.502593074@linuxfoundation.org> References: <20200407101459.502593074@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 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; }