From nobody Sun Apr 12 04:21:20 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 35732C00144 for ; Mon, 1 Aug 2022 13:25:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231449AbiHANZy (ORCPT ); Mon, 1 Aug 2022 09:25:54 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57010 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231491AbiHANZm (ORCPT ); Mon, 1 Aug 2022 09:25:42 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AD8FB6159; Mon, 1 Aug 2022 06:25:41 -0700 (PDT) Date: Mon, 01 Aug 2022 13:25:38 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1659360340; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=89+GN4tvYaXWzLnoWQk8SgCig5h3O2fWdKef/JpooCc=; b=W7IiaIxE38TrsFuNlxbA7vQ/CQ/UmpxC3tCJCKN04mrbfM4JMk1fyqSEM4K9tP8mX9PVBe U5CrWFyqRREFR0rDEF7BjbE9Qjfxw3FDJk7xFQ5pfVWLDn8aJnKj0QrTEXmQGjd3s1gddD uzFK1oZSqa36T5oJVXeeDI4VnscUK448Ef15fgdNi/sIHBlqiMAVET72biPok5csBHfmy+ 1bF6APf+8eDeSQP+78JilTO7IkAL+jx4sWTBV/l8MpsJhTPJKzHZcRQoOiSpY6cDJl0sY2 1iSywEtkfZUvfMD0/0Y9dFVK2ONoPuFBF2kmc9363p62ckcOsEuHcl5OIQAgGA== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1659360340; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=89+GN4tvYaXWzLnoWQk8SgCig5h3O2fWdKef/JpooCc=; b=D5HGMT7Oqh+9CXnGf/dnOFz0nmG36P80fj2iblZqtIEJDkTiDXHPru6tYmSmnuke8ul1Rj CeuLnkvAul4jVgDg== From: "tip-bot2 for Mathieu Desnoyers" Sender: tip-bot2@linutronix.de Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: sched/core] rseq: Kill process when unknown flags are encountered in ABI structures Cc: Mathieu Desnoyers , "Peter Zijlstra (Intel)" , Ingo Molnar , x86@kernel.org, linux-kernel@vger.kernel.org In-Reply-To: <20220622194617.1155957-2-mathieu.desnoyers@efficios.com> References: <20220622194617.1155957-2-mathieu.desnoyers@efficios.com> MIME-Version: 1.0 Message-ID: <165936033805.15455.17306563207808386039.tip-bot2@tip-bot2> Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The following commit has been merged into the sched/core branch of tip: Commit-ID: c17a6ff9321355487d7d5ccaa7d406a0ea06b6c4 Gitweb: https://git.kernel.org/tip/c17a6ff9321355487d7d5ccaa7d406a0e= a06b6c4 Author: Mathieu Desnoyers AuthorDate: Wed, 22 Jun 2022 15:46:17 -04:00 Committer: Ingo Molnar CommitterDate: Mon, 01 Aug 2022 15:21:42 +02:00 rseq: Kill process when unknown flags are encountered in ABI structures rseq_abi()->flags and rseq_abi()->rseq_cs->flags 29 upper bits are currently unused. The current behavior when those bits are set is to ignore them. This is not an ideal behavior, because when future features will start using those flags, if user-space fails to correctly validate that the kernel indeed supports those flags (e.g. with a new sys_rseq flags bit) before using them, it may incorrectly assume that the kernel will handle those flags way when in fact those will be silently ignored on older kernels. Validating that unused flags bits are cleared will allow a smoother transition when those flags will start to be used by allowing applications to fail early, and obviously, when they attempt to use the new flags on an older kernel that does not support them. Signed-off-by: Mathieu Desnoyers Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Ingo Molnar Link: https://lkml.kernel.org/r/20220622194617.1155957-2-mathieu.desnoyers@= efficios.com --- kernel/rseq.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/rseq.c b/kernel/rseq.c index 81d7dc8..bda8175 100644 --- a/kernel/rseq.c +++ b/kernel/rseq.c @@ -176,7 +176,7 @@ static int rseq_need_restart(struct task_struct *t, u32= cs_flags) u32 flags, event_mask; int ret; =20 - if (WARN_ON_ONCE(cs_flags & RSEQ_CS_NO_RESTART_FLAGS)) + if (WARN_ON_ONCE(cs_flags & RSEQ_CS_NO_RESTART_FLAGS) || cs_flags) return -EINVAL; =20 /* Get thread flags. */ @@ -184,7 +184,7 @@ static int rseq_need_restart(struct task_struct *t, u32= cs_flags) if (ret) return ret; =20 - if (WARN_ON_ONCE(flags & RSEQ_CS_NO_RESTART_FLAGS)) + if (WARN_ON_ONCE(flags & RSEQ_CS_NO_RESTART_FLAGS) || flags) return -EINVAL; =20 /*