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=ham 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 BF995C76186 for ; Thu, 18 Jul 2019 03:15:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9926721848 for ; Thu, 18 Jul 2019 03:15:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1563419732; bh=+AXeMsSpp/gq1taY1DVJ/SE3QdPb6OpklGsdgwC/kmY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=EJbG2rXYZHnpLC8W7Z5LpY4a7SVPGlVVLRlLvaOfubSp/SyTor1r0hDS6uIjwXTh8 SLzSOFSrPTZxmKuaVM8iX22tLb+RY4dX5zRrzew1YvKpFLXtDLYbSJwylDovWhwyj9 G5JR3a071MIwITNOIN59UBjUlrR+2tAvhur94SIY= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2392067AbfGRDPa (ORCPT ); Wed, 17 Jul 2019 23:15:30 -0400 Received: from mail.kernel.org ([198.145.29.99]:52594 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2392055AbfGRDP2 (ORCPT ); Wed, 17 Jul 2019 23:15:28 -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 435A021849; Thu, 18 Jul 2019 03:15:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1563419727; bh=+AXeMsSpp/gq1taY1DVJ/SE3QdPb6OpklGsdgwC/kmY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=bYUA1W6JQ+eRuaS2oRXpb09ma/mljxlYzUm2240/hCDIDkgJ9iMcY7FUbu/tEsQJD I1oc3LVMuw3ZGyFAQ8vl6+vOqp5iydHPlnZefTSlfoxKSB0WtqZCmyzAv216pZUVjg 7hYxK+TtkKHd+fdu1lw7aXv9DqApjCCB6gegli8Y= 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 4.4 29/40] perf/core: Fix perf_sample_regs_user() mm check Date: Thu, 18 Jul 2019 12:02:25 +0900 Message-Id: <20190718030049.572756691@linuxfoundation.org> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190718030039.676518610@linuxfoundation.org> References: <20190718030039.676518610@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@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 17230ca00bd4..41fe80e3380f 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -5078,7 +5078,7 @@ 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