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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 630DFC5B57D for ; Wed, 3 Jul 2019 02:21:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3D4A921874 for ; Wed, 3 Jul 2019 02:21:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1562120460; bh=oM1L33t+/hCOXb8D8GYlYwjleBds3DD6VTDRcYGc8YI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=N/oBp068nP19+ZeZBgKn/g5lLMguaznWpc8rgUbTvbDNmGJz51jnp0r1JH64n8F+E ta5T6oHgA7qxkZvf+9njw7u/1O6NBro5hgHRqD30P9YM5y0EQKzWsH8E7dnpKPUe/H MFRR6a4E5EoNbHhhk0w1HDybj60/8mpARK8aB9uQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727410AbfGCCQc (ORCPT ); Tue, 2 Jul 2019 22:16:32 -0400 Received: from mail.kernel.org ([198.145.29.99]:54844 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727957AbfGCCQb (ORCPT ); Tue, 2 Jul 2019 22:16:31 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id E37C721880; Wed, 3 Jul 2019 02:16:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1562120191; bh=oM1L33t+/hCOXb8D8GYlYwjleBds3DD6VTDRcYGc8YI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=caHK6xE9oB5WIO9R4K36/uStHNSli50VOh28jsDggxwfKhUi/P1JVvtagcVyv9MUF KQ9QmXqP6PIfyMfn5gRP8fL3DZRAaVrsOARI39wXfJZMeKtsb+57dlPqD2kd4Gt6f7 3DbNXifkrDWJiHTMfhqEKVkI93+dmYLxdBUMhfZU= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Peter Zijlstra , Ravi Bangoria , Young Xiao <92siuyang@gmail.com>, 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 AUTOSEL 4.19 04/26] perf/core: Fix perf_sample_regs_user() mm check Date: Tue, 2 Jul 2019 22:16:03 -0400 Message-Id: <20190703021625.18116-4-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190703021625.18116-1-sashal@kernel.org> References: <20190703021625.18116-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Peter Zijlstra [ 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 171b83ebed4a..3b61ff40bfe2 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -5906,7 +5906,7 @@ 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