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arc=none (no signatures found); dkim=fail (message has been altered, 2048-bit rsa key sha256) header.d=lechnology.com header.i=@lechnology.com header.b=xH5xwFlx x-bits=2048 x-keytype=rsa x-algorithm=sha256 x-selector=default; dmarc=none (p=none,has-list-id=yes,d=none) header.from=lechnology.com; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-category=clean score=-100 state=0 spamcause=gggruggvucftvghtrhhoucdtuddrgedtgedrudefgdduheejucdltddurdegtdefrddttddmucetufdoteggodetrfdotffvucfrrhhofhhilhgvmecuhfgrshhtofgrihhlnecuuegrihhlohhuthemuceftddtnecusecvtfgvtghiphhivghnthhsucdlqddutddtmdenucfjughrpefuvfhfhffkffgfgggjtgfgshhpjeesthejredttdefjeenucfhrhhomhepffgrvhhiugcunfgvtghhnhgvrhcuoegurghvihgusehlvggthhhnohhlohhghidrtghomheqnecukfhppedvtdelrddufedvrddukedtrdeijedpuddtkedrudelkedrhedrudegjeenucfrrghrrghmpehinhgvthepvddtledrudefvddrudektddrieejpdhhvghlohepvhhgvghrrdhkvghrnhgvlhdrohhrghdpmhgrihhlfhhrohhmpeeoshhtrggslhgvqdhofihnvghrsehvghgvrhdrkhgvrhhnvghlrdhorhhgqecuuefqffgjpeekuefkvffokffogfcuuffkkgfgpeeggedtudenucevlhhushhtvghrufhiiigvpeei; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=lechnology.com header.result=pass header_is_org_domain=yes Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934238AbeCSPzm (ORCPT ); Mon, 19 Mar 2018 11:55:42 -0400 Received: from vern.gendns.com ([206.190.152.46]:39298 "EHLO vern.gendns.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934117AbeCSPzP (ORCPT ); Mon, 19 Mar 2018 11:55:15 -0400 Subject: Re: [PATCH AUTOSEL for 4.15 104/124] clk: fix reentrancy of clk_enable() on UP systems To: Sasha Levin , "linux-kernel@vger.kernel.org" , "stable@vger.kernel.org" Cc: Stephen Boyd References: <20180319154645.11350-1-alexander.levin@microsoft.com> <20180319154645.11350-104-alexander.levin@microsoft.com> From: David Lechner Message-ID: <6a944b80-c86c-ca23-5ada-f088d84c9a80@lechnology.com> Date: Mon, 19 Mar 2018 10:55:16 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.6.0 MIME-Version: 1.0 In-Reply-To: <20180319154645.11350-104-alexander.levin@microsoft.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - vern.gendns.com X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - lechnology.com X-Get-Message-Sender-Via: vern.gendns.com: authenticated_id: davidmain+lechnology.com/only user confirmed/virtual account not confirmed X-Authenticated-Sender: vern.gendns.com: davidmain@lechnology.com X-Source: X-Source-Args: X-Source-Dir: Sender: stable-owner@vger.kernel.org X-Mailing-List: stable@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-Mailing-List: linux-kernel@vger.kernel.org List-ID: On 03/19/2018 10:48 AM, Sasha Levin wrote: > From: David Lechner > > [ Upstream commit a12aa8a68dfef5de181f2e555aa950a0ab05411f ] > > Reentrant calls to clk_enable() are not working on UP systems. This is > caused by the fact spin_trylock_irqsave() always returns true when > CONFIG_SMP=n (and CONFIG_DEBUG_SPINLOCK=n) which causes the reference > counting to not work correctly when clk_enable_lock() is called twice > before clk_enable_unlock() is called (this happens when clk_enable() > is called from within another clk_enable()). > > This fixes the problem by skipping the call to spin_trylock_irqsave() on UP > systems and relying solely on reference counting. We also make sure to set > flags in this case so that we are not returning an uninitialized value. > > Suggested-by: Stephen Boyd > Signed-off-by: David Lechner > Signed-off-by: Stephen Boyd > Signed-off-by: Sasha Levin > --- I don't know of any existing bugs in v4.15 that this fixes, so I don't think this really fits the criteria for stable.