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=-11.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS 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 D0830C7618F for ; Thu, 18 Jul 2019 14:52:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A4F492080D for ; Thu, 18 Jul 2019 14:52:34 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=zytor.com header.i=@zytor.com header.b="eJB1Eb8z" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390715AbfGROwd (ORCPT ); Thu, 18 Jul 2019 10:52:33 -0400 Received: from terminus.zytor.com ([198.137.202.136]:41681 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727730AbfGROwd (ORCPT ); Thu, 18 Jul 2019 10:52:33 -0400 Received: from terminus.zytor.com (localhost [127.0.0.1]) by terminus.zytor.com (8.15.2/8.15.2) with ESMTPS id x6IEq5jr2033251 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NO); Thu, 18 Jul 2019 07:52:05 -0700 DKIM-Filter: OpenDKIM Filter v2.11.0 terminus.zytor.com x6IEq5jr2033251 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=zytor.com; s=2019061801; t=1563461525; bh=A3YdLeuls4rg/UNG7F4whLwwLK+7fliRjPcY2W75YgY=; h=Date:From:Cc:Reply-To:In-Reply-To:References:To:Subject:From; b=eJB1Eb8zpeddDcWz5i6n14kUMN8OmNwZz0vpBcwh11I5q7LzNOYGXgRSf4pc2O1Xa UowH9r1hwVAsPgPQXnUfvXoBoMLKAdalBkiAf+sVElzdO96Lp66hJTKYWDBteWXrd5 FjYSS3XI2BZ6lOxF25akIElrzydTxKz2JiWduR8Z+aD9sci62Yy+4ehQs5rSRjymOx SJJ+EF0m5B+GDKOOFuAy0bzNK8tbTKFzCHhAnROnjsW4u7fPPdXouNEtI3wqHk2Bsp V5DH5kOqNIc56u92L71E0CwdNS3mMQyVkrIeIrTTyJBYCbvOW3MW5NUywVSqBN/lw6 p62Wm/ZglMbww== Received: (from tipbot@localhost) by terminus.zytor.com (8.15.2/8.15.2/Submit) id x6IEq4ba2033246; Thu, 18 Jul 2019 07:52:04 -0700 Date: Thu, 18 Jul 2019 07:52:04 -0700 X-Authentication-Warning: terminus.zytor.com: tipbot set sender to tipbot@zytor.com using -f From: tip-bot for Peter Zijlstra Message-ID: Cc: tglx@linutronix.de, mingo@kernel.org, vegard.nossum@oracle.com, devel@etsukata.com, linux-kernel@vger.kernel.org, hpa@zytor.com, joel@joelfernandes.org, peterz@infradead.org Reply-To: peterz@infradead.org, joel@joelfernandes.org, hpa@zytor.com, linux-kernel@vger.kernel.org, mingo@kernel.org, vegard.nossum@oracle.com, devel@etsukata.com, tglx@linutronix.de In-Reply-To: <20190718085754.GM3402@hirez.programming.kicks-ass.net> References: <20190718085754.GM3402@hirez.programming.kicks-ass.net> To: linux-tip-commits@vger.kernel.org Subject: [tip:core/urgent] stacktrace: Force USER_DS for stack_trace_save_user() Git-Commit-ID: cac9b9a4b08304f11daace03b8b48659355e44c1 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: cac9b9a4b08304f11daace03b8b48659355e44c1 Gitweb: https://git.kernel.org/tip/cac9b9a4b08304f11daace03b8b48659355e44c1 Author: Peter Zijlstra AuthorDate: Thu, 18 Jul 2019 10:47:47 +0200 Committer: Thomas Gleixner CommitDate: Thu, 18 Jul 2019 16:47:24 +0200 stacktrace: Force USER_DS for stack_trace_save_user() When walking userspace stacks, USER_DS needs to be set, otherwise access_ok() will not function as expected. Reported-by: Vegard Nossum Reported-by: Eiichi Tsukata Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Thomas Gleixner Tested-by: Vegard Nossum Reviewed-by: Joel Fernandes (Google) Link: https://lkml.kernel.org/r/20190718085754.GM3402@hirez.programming.kicks-ass.net --- kernel/stacktrace.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/kernel/stacktrace.c b/kernel/stacktrace.c index e6a02b274b73..f5440abb7532 100644 --- a/kernel/stacktrace.c +++ b/kernel/stacktrace.c @@ -226,12 +226,17 @@ unsigned int stack_trace_save_user(unsigned long *store, unsigned int size) .store = store, .size = size, }; + mm_segment_t fs; /* Trace user stack if not a kernel thread */ if (current->flags & PF_KTHREAD) return 0; + fs = get_fs(); + set_fs(USER_DS); arch_stack_walk_user(consume_entry, &c, task_pt_regs(current)); + set_fs(fs); + return c.len; } #endif