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=-8.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS 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 D3AEBC3A5A1 for ; Thu, 22 Aug 2019 13:22:20 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 89AA02070B for ; Thu, 22 Aug 2019 13:22:20 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 89AA02070B Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ellerman.id.au Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from bilbo.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 46DlZ168sSzDqNt for ; Thu, 22 Aug 2019 23:22:17 +1000 (AEST) Received: from ozlabs.org (bilbo.ozlabs.org [IPv6:2401:3900:2:1::2]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 46DlGc12jqzDrPb for ; Thu, 22 Aug 2019 23:08:56 +1000 (AEST) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=ellerman.id.au Received: by ozlabs.org (Postfix, from userid 1034) id 46DlGb4DCwz9sP6; Thu, 22 Aug 2019 23:08:55 +1000 (AEST) X-powerpc-patch-notification: thanks X-powerpc-patch-commit: 56090a3902c80c296e822d11acdb6a101b322c52 In-Reply-To: <20190718051139.74787-2-aik@ozlabs.ru> To: Alexey Kardashevskiy , linuxppc-dev@lists.ozlabs.org From: Michael Ellerman Subject: Re: [PATCH kernel v5 1/4] powerpc/powernv/ioda: Fix race in TCE level allocation Message-Id: <46DlGb4DCwz9sP6@ozlabs.org> Date: Thu, 22 Aug 2019 23:08:55 +1000 (AEST) X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Sam Bobroff , Alistair Popple , stable@vger.kernel.org, Alexey Kardashevskiy , Oliver O'Halloran , David Gibson Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Thu, 2019-07-18 at 05:11:36 UTC, Alexey Kardashevskiy wrote: > pnv_tce() returns a pointer to a TCE entry and originally a TCE table > would be pre-allocated. For the default case of 2GB window the table > needs only a single level and that is fine. However if more levels are > requested, it is possible to get a race when 2 threads want a pointer > to a TCE entry from the same page of TCEs. > > This adds cmpxchg to handle the race. Note that once TCE is non-zero, > it cannot become zero again. > > CC: stable@vger.kernel.org # v4.19+ > Fixes: a68bd1267b72 ("powerpc/powernv/ioda: Allocate indirect TCE levels on demand") > Signed-off-by: Alexey Kardashevskiy Series applied to powerpc next, thanks. https://git.kernel.org/powerpc/c/56090a3902c80c296e822d11acdb6a101b322c52 cheers