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=-19.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 36613C49361 for ; Mon, 28 Jun 2021 14:34:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1FE4E61C9A for ; Mon, 28 Jun 2021 14:34:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233217AbhF1OhN (ORCPT ); Mon, 28 Jun 2021 10:37:13 -0400 Received: from mail.kernel.org ([198.145.29.99]:36732 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234582AbhF1OaJ (ORCPT ); Mon, 28 Jun 2021 10:30:09 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 8D1BD61C94; Mon, 28 Jun 2021 14:26:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1624890388; bh=sY5GkAsi8S0B9bZc0hbk9eW1X2mvJjUu4b2F0g8rmGg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=bRxOMpnE1hDtJ0iScUOlm8kV4ZkZvueeO10Isx7svTDPWydqWw754jC/9zQWwoFAG 6KVqOYgQSygbgW/wovqGPKUF63u194ui/Af9z16lvDzJcxWCowmxDM74ZwcGOlB4wb AtZCs8pmukmtEQah21BezTxMcWySsm5RcirEv7BFzHLzsFI0pdIoK2Brp7V20CalZd exAjWcYOC87FDYEUt4XfHjX81vCUslO+ZFTPVn1oDrEQZlaAgq8T9gdhw1iGmLT2Cw Qxh2Uc2Whze5p0sjkfSw0vpmKQyxLeK06gCQhw5rmSQdxHqt0Jz/dmKHQFPux/fAbN QwaMhZv+ze+3A== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Thomas Gleixner , Ingo Molnar , Sasha Levin Subject: [PATCH 5.10 021/101] perf/x86/intel/lbr: Zero the xstate buffer on allocation Date: Mon, 28 Jun 2021 10:24:47 -0400 Message-Id: <20210628142607.32218-22-sashal@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210628142607.32218-1-sashal@kernel.org> References: <20210628142607.32218-1-sashal@kernel.org> MIME-Version: 1.0 X-KernelTest-Patch: http://kernel.org/pub/linux/kernel/v5.x/stable-review/patch-5.10.47-rc1.gz X-KernelTest-Tree: git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git X-KernelTest-Branch: linux-5.10.y X-KernelTest-Patches: git://git.kernel.org/pub/scm/linux/kernel/git/stable/stable-queue.git X-KernelTest-Version: 5.10.47-rc1 X-KernelTest-Deadline: 2021-06-30T14:25+00:00 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Thomas Gleixner [ Upstream commit 7f049fbdd57f6ea71dc741d903c19c73b2f70950 ] XRSTORS requires a valid xstate buffer to work correctly. XSAVES does not guarantee to write a fully valid buffer according to the SDM: "XSAVES does not write to any parts of the XSAVE header other than the XSTATE_BV and XCOMP_BV fields." XRSTORS triggers a #GP: "If bytes 63:16 of the XSAVE header are not all zero." It's dubious at best how this can work at all when the buffer is not zeroed before use. Allocate the buffers with __GFP_ZERO to prevent XRSTORS failure. Fixes: ce711ea3cab9 ("perf/x86/intel/lbr: Support XSAVES/XRSTORS for LBR context switch") Signed-off-by: Thomas Gleixner Signed-off-by: Ingo Molnar Link: https://lore.kernel.org/r/87wnr0wo2z.ffs@nanos.tec.linutronix.de Signed-off-by: Sasha Levin --- arch/x86/events/intel/lbr.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/x86/events/intel/lbr.c b/arch/x86/events/intel/lbr.c index 6c1231837382..29ec4fe48507 100644 --- a/arch/x86/events/intel/lbr.c +++ b/arch/x86/events/intel/lbr.c @@ -730,7 +730,8 @@ void reserve_lbr_buffers(void) if (!kmem_cache || cpuc->lbr_xsave) continue; - cpuc->lbr_xsave = kmem_cache_alloc_node(kmem_cache, GFP_KERNEL, + cpuc->lbr_xsave = kmem_cache_alloc_node(kmem_cache, + GFP_KERNEL | __GFP_ZERO, cpu_to_node(cpu)); } } -- 2.30.2