From nobody Sat Apr 11 06:31:25 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 BAD42C00140 for ; Mon, 15 Aug 2022 08:48:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231748AbiHOIsW (ORCPT ); Mon, 15 Aug 2022 04:48:22 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41152 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229740AbiHOIsT (ORCPT ); Mon, 15 Aug 2022 04:48:19 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4F420201BD; Mon, 15 Aug 2022 01:48:18 -0700 (PDT) Date: Mon, 15 Aug 2022 08:48:14 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1660553295; 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=IQWaK8qY9Rujxh5W8uD3V8R2QS0vMhGEuhjPCTuRwls=; b=CFnq38Jv4Tv7DdZXatgSSbvmXgToh6MDdUX2c12W0K20KA+khqiM9npOUq532h9tUywYQe SaLXjHFKahEsvLHs/bylDHaZUc1NB5P9Sm8xFZf4COkFck2Hcmn0/5e4KPNAwUpvccDOfd 2mnj1fE+S0UkDTRXZFtge/EkxULjjvtEBv2OAMWK3GHXg9wNnX4IlbwVTvHqGJ7Y5zyfUn B1z0ZZatqB5+uMJQVIIIHP9BcD0rJLWu2QrlYv2sj7rYR9+S6kK3jdSqYCTnnW0cYmJnbz nyG8ExWyzNDHsdm550Jr4sdumT6Y2JIKU7Dm2V54FkwUY8PXeO6M1PwDUje1Yw== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1660553295; 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=IQWaK8qY9Rujxh5W8uD3V8R2QS0vMhGEuhjPCTuRwls=; b=Uimj+IhKe/i5RBJFtwJv1o1V+LRKQs2OnOwtNmReyYwZsG5m8KukOKlTRXz9gAOx8//7iq 0oXBlCVtGFCsTICg== From: "tip-bot2 for Nadav Amit" Sender: tip-bot2@linutronix.de Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: perf/urgent] x86/kprobes: Fix JNG/JNLE emulation Cc: Nadav Amit , Ingo Molnar , stable@vger.kernel.org, x86@kernel.org, linux-kernel@vger.kernel.org In-Reply-To: <20220813225943.143767-1-namit@vmware.com> References: <20220813225943.143767-1-namit@vmware.com> MIME-Version: 1.0 Message-ID: <166055329407.401.4288744100235226056.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 perf/urgent branch of tip: Commit-ID: 8924779df820c53875abaeb10c648e9cb75b46d4 Gitweb: https://git.kernel.org/tip/8924779df820c53875abaeb10c648e9cb= 75b46d4 Author: Nadav Amit AuthorDate: Sat, 13 Aug 2022 15:59:43 -07:00 Committer: Ingo Molnar CommitterDate: Sun, 14 Aug 2022 11:27:17 +02:00 x86/kprobes: Fix JNG/JNLE emulation When kprobes emulates JNG/JNLE instructions on x86 it uses the wrong condition. For JNG (opcode: 0F 8E), according to Intel SDM, the jump is performed if (ZF =3D=3D 1 or SF !=3D OF). However the kernel emulation currently uses 'and' instead of 'or'. As a result, setting a kprobe on JNG/JNLE might cause the kernel to behave incorrectly whenever the kprobe is hit. Fix by changing the 'and' to 'or'. Fixes: 6256e668b7af ("x86/kprobes: Use int3 instead of debug trap for singl= e-step") Signed-off-by: Nadav Amit Signed-off-by: Ingo Molnar Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20220813225943.143767-1-namit@vmware.com --- arch/x86/kernel/kprobes/core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c index 74167dc..4c3c27b 100644 --- a/arch/x86/kernel/kprobes/core.c +++ b/arch/x86/kernel/kprobes/core.c @@ -505,7 +505,7 @@ static void kprobe_emulate_jcc(struct kprobe *p, struct= pt_regs *regs) match =3D ((regs->flags & X86_EFLAGS_SF) >> X86_EFLAGS_SF_BIT) ^ ((regs->flags & X86_EFLAGS_OF) >> X86_EFLAGS_OF_BIT); if (p->ainsn.jcc.type >=3D 0xe) - match =3D match && (regs->flags & X86_EFLAGS_ZF); + match =3D match || (regs->flags & X86_EFLAGS_ZF); } __kprobe_emulate_jmp(p, regs, (match && !invert) || (!match && invert)); }