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=-9.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,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 5C3DCC282CE for ; Mon, 15 Apr 2019 06:01:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 25EE320881 for ; Mon, 15 Apr 2019 06:01:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1555308103; bh=/MzyQFL/wBpTLdxwMWluiFvFv22skfYJ0MfNoQhkvLc=; h=From:To:Cc:Subject:Date:List-ID:From; b=HaoWqPe5bIvRcCnkoDDgAbeUzBmq3834XG44ysTcNYcHcH0lamMcokZd64kRqf5vB HxS5e+ojrXIh+Wt0C+suQJlCMTEP/mn5IYco4UGC9g6yDgl6iQWngD3UdeAtxGhtuS v9jY3OoDCNHMzaVJgUafDQL80zJx+/inuWgCoTkU= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726197AbfDOGBm (ORCPT ); Mon, 15 Apr 2019 02:01:42 -0400 Received: from mail.kernel.org ([198.145.29.99]:37710 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725777AbfDOGBl (ORCPT ); Mon, 15 Apr 2019 02:01:41 -0400 Received: from localhost.localdomain (NE2965lan1.rev.em-net.ne.jp [210.141.244.193]) (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 9F58520825; Mon, 15 Apr 2019 06:01:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1555308101; bh=/MzyQFL/wBpTLdxwMWluiFvFv22skfYJ0MfNoQhkvLc=; h=From:To:Cc:Subject:Date:From; b=epTU/GE4TqI1DB6MPMBNOHFOxaOJyLsulNol1x/K4kh/T6qYb/3/w49iRWQSi55ev F/YiIkxMJ3KNnTfemymHjM+p4ZpwuOJV9HyERfQ2mJZ0yD4mnRlo57llpdMkbzJXQ6 4AEK8WwdDAe2AZb/3l6Rpt/MTZnlaJC2bNIwlnYY= From: Masami Hiramatsu To: Ingo Molnar Cc: Anil S Keshavamurthy , "David S . Miller" , Linus Torvalds , "Naveen N . Rao" , Peter Zijlstra , Thomas Gleixner , Masami Hiramatsu , stable@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH -tip] kprobes: Fix an inverted result check for reusing optimized probe Date: Mon, 15 Apr 2019 15:01:25 +0900 Message-Id: <155530808559.32517.539898325433642204.stgit@devnote2> X-Mailer: git-send-email 2.17.1 User-Agent: StGit/0.17.1-dirty MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Fix an inverted result check for reusing unused kprobe correctly. This has been introduced by commit 819319fc9346 ("kprobes: Return error if we fail to reuse kprobe instead of BUG_ON()"), which missed to handle the return value of kprobe_optready() as error-value. In reality, the kprobe_optready() returns a bool result, so "true" case must be passed instead of 0. This causes some errors on kprobe boot-time selftests on arm. [ 4.563544] Beginning kprobe tests... [ 4.563648] Probe ARM code [ 4.563733] kprobe [ 4.564700] kretprobe [ 4.565538] ARM instruction simulation [ 4.565671] Check decoding tables [ 4.565883] Run test cases [ 5.070700] FAIL: test_case_handler not run [ 5.070938] FAIL: Test andge r10, r11, r14, asr r7 [ 5.071118] FAIL: Scenario 11 ... [ 74.174729] FAIL: Scenario 7 [ 74.211776] Total instruction simulation tests=1631, pass=1433 fail=198 [ 74.212168] kprobe tests failed This can happen if an optimized probe is unregistered and next kprobe is registered on same address until the previous probe is not reclaimed. If this happens, a hidden aggregated probe may be kept in memory, and no new kprobe can probe same address. Also, in that case register_kprobe() will return "1" instead of minus error value, which can mislead caller logic. Signed-off-by: Masami Hiramatsu Fixes: 819319fc9346 ("kprobes: Return error if we fail to reuse kprobe instead of BUG_ON()") Cc: stable@vger.kernel.org # v5.0+ --- kernel/kprobes.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) diff --git a/kernel/kprobes.c b/kernel/kprobes.c index c83e54727131..b1ea30a5540e 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -709,7 +709,6 @@ static void unoptimize_kprobe(struct kprobe *p, bool force) static int reuse_unused_kprobe(struct kprobe *ap) { struct optimized_kprobe *op; - int ret; /* * Unused kprobe MUST be on the way of delayed unoptimizing (means @@ -720,9 +719,8 @@ static int reuse_unused_kprobe(struct kprobe *ap) /* Enable the probe again */ ap->flags &= ~KPROBE_FLAG_DISABLED; /* Optimize it again (remove from op->list) */ - ret = kprobe_optready(ap); - if (ret) - return ret; + if (!kprobe_optready(ap)) + return -EINVAL; optimize_kprobe(ap); return 0;