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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7D2FFC19F2C for ; Tue, 2 Aug 2022 11:03:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236759AbiHBLDQ (ORCPT ); Tue, 2 Aug 2022 07:03:16 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39186 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236751AbiHBLDL (ORCPT ); Tue, 2 Aug 2022 07:03:11 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B43B45006B; Tue, 2 Aug 2022 04:03:10 -0700 (PDT) Date: Tue, 02 Aug 2022 11:03:06 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1659438188; 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=quj/DIYnqZXApkrdHkfR5Acc22JBv5Wfc2X2gChjjg4=; b=bIa86NKUD9QHxI3b3vHNYYHQd2DL+0lfw2tluWCPaoGn9K9BqXflJT4TAofF69VQI491SC XciKyYResPAHBT2dNqrk7GI6qJbXixhpRgETjCq8cjBsLq0J3Y0dztQl5zNG16uBnP8TAq nh+ULaW7AbrYFgb/nETgt9vtqoFUuy0O9CUnhohuey+KqoYZSAGTk6tSgB6avhQ5QhDjVh Sk5etpmNhsH5wLiM55Nzvq5tHiBB5C9UMFORyKsXAfpSMnDIS4Nlj9dnMi874ukOsyGZsK lKZlMsPaQej8KRnAW44dJzw4eSxsZPvl2dQMDBZb3qph9OCqNYX0lbeYo8BI4Q== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1659438188; 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=quj/DIYnqZXApkrdHkfR5Acc22JBv5Wfc2X2gChjjg4=; b=8WfWDHfBERUUKIpq/jyzLcKxWTlUfoewKUQzaYxheBI0ZOs5ErkU+fvEAKln8OTlshzU1j Pfq0ujLg8z6uG7Dw== From: "tip-bot2 for Masami Hiramatsu (Google)" 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: Update kcb status flag after singlestepping Cc: deso@posteo.net, "Masami Hiramatsu (Google)" , Ingo Molnar , stable@vger.kernel.org, x86@kernel.org, linux-kernel@vger.kernel.org In-Reply-To: <20220727210136.jjgc3lpqeq42yr3m@muellerd-fedora-PC2BDTX9> References: <20220727210136.jjgc3lpqeq42yr3m@muellerd-fedora-PC2BDTX9> MIME-Version: 1.0 Message-ID: <165943818693.15455.252081735537091891.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: dec8784c9088b131a1523f582c2194cfc8107dc0 Gitweb: https://git.kernel.org/tip/dec8784c9088b131a1523f582c2194cfc81= 07dc0 Author: Masami Hiramatsu (Google) AuthorDate: Tue, 02 Aug 2022 15:04:16 +09:00 Committer: Ingo Molnar CommitterDate: Tue, 02 Aug 2022 12:35:04 +02:00 x86/kprobes: Update kcb status flag after singlestepping Fix kprobes to update kcb (kprobes control block) status flag to KPROBE_HIT_SSDONE even if the kp->post_handler is not set. This bug may cause a kernel panic if another INT3 user runs right after kprobes because kprobe_int3_handler() misunderstands the INT3 is kprobe's single stepping INT3. Fixes: 6256e668b7af ("x86/kprobes: Use int3 instead of debug trap for single-= step") Reported-by: Daniel M=C3=BCller Signed-off-by: Masami Hiramatsu (Google) Signed-off-by: Ingo Molnar Tested-by: Daniel M=C3=BCller Cc: stable@vger.kernel.org Link: https://lore.kernel.org/all/20220727210136.jjgc3lpqeq42yr3m@muellerd-fe= dora-PC2BDTX9 Link: https://lore.kernel.org/r/165942025658.342061.12452378391879093249.stgi= t@devnote2 --- arch/x86/kernel/kprobes/core.c | 18 +++++++++++------- 1 file changed, 11 insertions(+), 7 deletions(-) diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c index 7c4ab88..74167dc 100644 --- a/arch/x86/kernel/kprobes/core.c +++ b/arch/x86/kernel/kprobes/core.c @@ -814,16 +814,20 @@ set_current_kprobe(struct kprobe *p, struct pt_regs *re= gs, static void kprobe_post_process(struct kprobe *cur, struct pt_regs *regs, struct kprobe_ctlblk *kcb) { - if ((kcb->kprobe_status !=3D KPROBE_REENTER) && cur->post_handler) { - kcb->kprobe_status =3D KPROBE_HIT_SSDONE; - cur->post_handler(cur, regs, 0); - } - /* Restore back the original saved kprobes variables and continue. */ - if (kcb->kprobe_status =3D=3D KPROBE_REENTER) + if (kcb->kprobe_status =3D=3D KPROBE_REENTER) { + /* This will restore both kcb and current_kprobe */ restore_previous_kprobe(kcb); - else + } else { + /* + * Always update the kcb status because + * reset_curent_kprobe() doesn't update kcb. + */ + kcb->kprobe_status =3D KPROBE_HIT_SSDONE; + if (cur->post_handler) + cur->post_handler(cur, regs, 0); reset_current_kprobe(); + } } NOKPROBE_SYMBOL(kprobe_post_process); =20