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=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,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 B2B8FC76192 for ; Thu, 18 Jul 2019 03:26:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 853A3206DD for ; Thu, 18 Jul 2019 03:26:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1563420368; bh=fJfvizMuZ0wwxJyI/5+W59j2LgVlpJMJDygCtPoV50Y=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=Ud/0RbbquU9t1mUe9NUeyazgHL9x0mkBVbG6q4etjMe1calPS5SK6PoylirRabdtr 1K7kmE9l3OoW6XJq844gAWR2TTolD86Ehn/1WKQoo1INqYbbADOQIogTXfEXpk8FAL TixfL/bGLYO/qFZViW3LwW9e6HDUasm06lYkWzgM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390420AbfGRD0H (ORCPT ); Wed, 17 Jul 2019 23:26:07 -0400 Received: from mail.kernel.org ([198.145.29.99]:35004 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389616AbfGRDEH (ORCPT ); Wed, 17 Jul 2019 23:04:07 -0400 Received: from localhost (115.42.148.210.bf.2iij.net [210.148.42.115]) (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 A5BC0204EC; Thu, 18 Jul 2019 03:04:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1563419047; bh=fJfvizMuZ0wwxJyI/5+W59j2LgVlpJMJDygCtPoV50Y=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=a81bW9uwgSMQfH3cRXCK3E2dRCHivJnGW6BA9KseLxjPWujLtra44ahRG1MdM77P/ ZXXq9Q3YaUw1w3E7GuL9qBNpU3lqzjzkQhK21UrrizhBoyqpFwPFFOz3GwFJjrzKVO hVnQx+VwBiMWvMdGbWALRLSwjPimxzJ1Q3GSUZm0= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Ravi Bangoria , Young Xiao <92siuyang@gmail.com>, "Peter Zijlstra (Intel)" , Will Deacon , Arnaldo Carvalho de Melo , Frederic Weisbecker , Jiri Olsa , Linus Torvalds , Michael Ellerman , "Naveen N. Rao" , Stephane Eranian , Thomas Gleixner , Ingo Molnar , Sasha Levin Subject: [PATCH 5.1 15/54] perf/core: Fix perf_sample_regs_user() mm check Date: Thu, 18 Jul 2019 12:01:10 +0900 Message-Id: <20190718030054.593476243@linuxfoundation.org> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190718030053.287374640@linuxfoundation.org> References: <20190718030053.287374640@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org [ Upstream commit 085ebfe937d7a7a5df1729f35a12d6d655fea68c ] perf_sample_regs_user() uses 'current->mm' to test for the presence of userspace, but this is insufficient, consider use_mm(). A better test is: '!(current->flags & PF_KTHREAD)', exec() clears PF_KTHREAD after it sets the new ->mm but before it drops to userspace for the first time. Possibly obsoletes: bf05fc25f268 ("powerpc/perf: Fix oops when kthread execs user process") Reported-by: Ravi Bangoria Reported-by: Young Xiao <92siuyang@gmail.com> Signed-off-by: Peter Zijlstra (Intel) Acked-by: Will Deacon Cc: Arnaldo Carvalho de Melo Cc: Frederic Weisbecker Cc: Jiri Olsa Cc: Linus Torvalds Cc: Michael Ellerman Cc: Naveen N. Rao Cc: Peter Zijlstra Cc: Stephane Eranian Cc: Thomas Gleixner Fixes: 4018994f3d87 ("perf: Add ability to attach user level registers dump to sample") Signed-off-by: Ingo Molnar Signed-off-by: Sasha Levin --- kernel/events/core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/events/core.c b/kernel/events/core.c index dc7dead2d2cc..f33bd0a89391 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -5913,7 +5913,7 @@ static void perf_sample_regs_user(struct perf_regs *regs_user, if (user_mode(regs)) { regs_user->abi = perf_reg_abi(current); regs_user->regs = regs; - } else if (current->mm) { + } else if (!(current->flags & PF_KTHREAD)) { perf_get_regs_user(regs_user, regs, regs_user_copy); } else { regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE; -- 2.20.1