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 95076C433DF for ; Tue, 9 Jun 2020 00:18:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7038E2078D for ; Tue, 9 Jun 2020 00:18:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591661880; bh=jAO10dhZ0/bvgXRJ5ALw6c+WQy6MKBhxPTMd0JqViQU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=xuRkR9aGu7y5laLSroE8TG5ESNB8qqGXYXaVQ7y6GjbGJ+VSDhyRN4VAFfbnIPMGk KTuotiU//YHsJXUjNgA9FzIGXD58Pqu9J6t/vQ73L5XrGE8/ojmlEdre7v3WI82b9T Zr1W0GoOuaOBoShrbl6OdWr6cLmBR2L3xkAXMjwY= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730701AbgFHXSs (ORCPT ); Mon, 8 Jun 2020 19:18:48 -0400 Received: from mail.kernel.org ([198.145.29.99]:35934 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728719AbgFHXPK (ORCPT ); Mon, 8 Jun 2020 19:15:10 -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 921F121501; Mon, 8 Jun 2020 23:15:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591658110; bh=jAO10dhZ0/bvgXRJ5ALw6c+WQy6MKBhxPTMd0JqViQU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Yp0wg583cF/EJPOSbFpdN9IqDseS+8SjiNe+I6RNd5lKW+bWA7Sg7dxHXYpvHm0oJ Gfa7aIoiLnNdXok2JCtEkj8WOuCcRik8BW7c5JwB/bgqLCUFXFyBE7/2mT9cDNm7nC lai9bI4IGeA7KA8S0NjsuY0CxyU/sYX4FnL+EWak= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Keno Fischer , Will Deacon , Sudeep Holla , Bin Lu , Catalin Marinas , Greg Kroah-Hartman , linux-arm-kernel@lists.infradead.org Subject: [PATCH AUTOSEL 5.6 149/606] arm64: Fix PTRACE_SYSEMU semantics Date: Mon, 8 Jun 2020 19:04:34 -0400 Message-Id: <20200608231211.3363633-149-sashal@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200608231211.3363633-1-sashal@kernel.org> References: <20200608231211.3363633-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Keno Fischer commit 1cf6022bd9161081215028203919c33fcfa6debb upstream. Quoth the man page: ``` If the tracee was restarted by PTRACE_SYSCALL or PTRACE_SYSEMU, the tracee enters syscall-enter-stop just prior to entering any system call (which will not be executed if the restart was using PTRACE_SYSEMU, regardless of any change made to registers at this point or how the tracee is restarted after this stop). ``` The parenthetical comment is currently true on x86 and powerpc, but not currently true on arm64. arm64 re-checks the _TIF_SYSCALL_EMU flag after the syscall entry ptrace stop. However, at this point, it reflects which method was used to re-start the syscall at the entry stop, rather than the method that was used to reach it. Fix that by recording the original flag before performing the ptrace stop, bringing the behavior in line with documentation and x86/powerpc. Fixes: f086f67485c5 ("arm64: ptrace: add support for syscall emulation") Cc: # 5.3.x- Signed-off-by: Keno Fischer Acked-by: Will Deacon Tested-by: Sudeep Holla Tested-by: Bin Lu [catalin.marinas@arm.com: moved 'flags' bit masking] [catalin.marinas@arm.com: changed 'flags' type to unsigned long] Signed-off-by: Catalin Marinas Signed-off-by: Greg Kroah-Hartman --- arch/arm64/kernel/ptrace.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c index cd6e5fa48b9c..c30f77bd875f 100644 --- a/arch/arm64/kernel/ptrace.c +++ b/arch/arm64/kernel/ptrace.c @@ -1829,10 +1829,11 @@ static void tracehook_report_syscall(struct pt_regs *regs, int syscall_trace_enter(struct pt_regs *regs) { - if (test_thread_flag(TIF_SYSCALL_TRACE) || - test_thread_flag(TIF_SYSCALL_EMU)) { + unsigned long flags = READ_ONCE(current_thread_info()->flags); + + if (flags & (_TIF_SYSCALL_EMU | _TIF_SYSCALL_TRACE)) { tracehook_report_syscall(regs, PTRACE_SYSCALL_ENTER); - if (!in_syscall(regs) || test_thread_flag(TIF_SYSCALL_EMU)) + if (!in_syscall(regs) || (flags & _TIF_SYSCALL_EMU)) return -1; } -- 2.25.1