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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 1A25AC4646A for ; Wed, 12 Sep 2018 06:54:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C523F20833 for ; Wed, 12 Sep 2018 06:54:57 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C523F20833 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=zytor.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727626AbeILL6B (ORCPT ); Wed, 12 Sep 2018 07:58:01 -0400 Received: from terminus.zytor.com ([198.137.202.136]:58681 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726149AbeILL6B (ORCPT ); Wed, 12 Sep 2018 07:58:01 -0400 Received: from terminus.zytor.com (localhost [127.0.0.1]) by terminus.zytor.com (8.15.2/8.15.2) with ESMTPS id w8C6rVl62538682 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Tue, 11 Sep 2018 23:53:31 -0700 Received: (from tipbot@localhost) by terminus.zytor.com (8.15.2/8.15.2/Submit) id w8C6rV7P2538679; Tue, 11 Sep 2018 23:53:31 -0700 Date: Tue, 11 Sep 2018 23:53:31 -0700 X-Authentication-Warning: terminus.zytor.com: tipbot set sender to tipbot@zytor.com using -f From: tip-bot for Masami Hiramatsu Message-ID: Cc: davem@davemloft.net, linux-kernel@vger.kernel.org, anil.s.keshavamurthy@intel.com, hpa@zytor.com, naveen.n.rao@linux.vnet.ibm.com, mhiramat@kernel.org, torvalds@linux-foundation.org, mingo@kernel.org, tglx@linutronix.de, peterz@infradead.org Reply-To: tglx@linutronix.de, mingo@kernel.org, peterz@infradead.org, anil.s.keshavamurthy@intel.com, davem@davemloft.net, linux-kernel@vger.kernel.org, torvalds@linux-foundation.org, naveen.n.rao@linux.vnet.ibm.com, mhiramat@kernel.org, hpa@zytor.com In-Reply-To: <153666124040.21306.14150398706331307654.stgit@devbox> References: <153666124040.21306.14150398706331307654.stgit@devbox> To: linux-tip-commits@vger.kernel.org Subject: [tip:perf/core] kprobes: Return error if we fail to reuse kprobe instead of BUG_ON() Git-Commit-ID: 819319fc93461c07b9cdb3064f154bd8cfd48172 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 819319fc93461c07b9cdb3064f154bd8cfd48172 Gitweb: https://git.kernel.org/tip/819319fc93461c07b9cdb3064f154bd8cfd48172 Author: Masami Hiramatsu AuthorDate: Tue, 11 Sep 2018 19:20:40 +0900 Committer: Ingo Molnar CommitDate: Wed, 12 Sep 2018 08:01:16 +0200 kprobes: Return error if we fail to reuse kprobe instead of BUG_ON() Make reuse_unused_kprobe() to return error code if it fails to reuse unused kprobe for optprobe instead of calling BUG_ON(). Signed-off-by: Masami Hiramatsu Cc: Anil S Keshavamurthy Cc: David S . Miller Cc: Linus Torvalds Cc: Naveen N . Rao Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/153666124040.21306.14150398706331307654.stgit@devbox Signed-off-by: Ingo Molnar --- kernel/kprobes.c | 27 ++++++++++++++++++++------- 1 file changed, 20 insertions(+), 7 deletions(-) diff --git a/kernel/kprobes.c b/kernel/kprobes.c index 277a6cbe83db..63c342e5e6c3 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -700,9 +700,10 @@ static void unoptimize_kprobe(struct kprobe *p, bool force) } /* Cancel unoptimizing for reusing */ -static void reuse_unused_kprobe(struct kprobe *ap) +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 @@ -713,8 +714,12 @@ static void reuse_unused_kprobe(struct kprobe *ap) /* Enable the probe again */ ap->flags &= ~KPROBE_FLAG_DISABLED; /* Optimize it again (remove from op->list) */ - BUG_ON(!kprobe_optready(ap)); + ret = kprobe_optready(ap); + if (ret) + return ret; + optimize_kprobe(ap); + return 0; } /* Remove optimized instructions */ @@ -939,11 +944,16 @@ static void __disarm_kprobe(struct kprobe *p, bool reopt) #define kprobe_disarmed(p) kprobe_disabled(p) #define wait_for_kprobe_optimizer() do {} while (0) -/* There should be no unused kprobes can be reused without optimization */ -static void reuse_unused_kprobe(struct kprobe *ap) +static int reuse_unused_kprobe(struct kprobe *ap) { + /* + * If the optimized kprobe is NOT supported, the aggr kprobe is + * released at the same time that the last aggregated kprobe is + * unregistered. + * Thus there should be no chance to reuse unused kprobe. + */ printk(KERN_ERR "Error: There should be no unused kprobe here.\n"); - BUG_ON(kprobe_unused(ap)); + return -EINVAL; } static void free_aggr_kprobe(struct kprobe *p) @@ -1315,9 +1325,12 @@ static int register_aggr_kprobe(struct kprobe *orig_p, struct kprobe *p) goto out; } init_aggr_kprobe(ap, orig_p); - } else if (kprobe_unused(ap)) + } else if (kprobe_unused(ap)) { /* This probe is going to die. Rescue it */ - reuse_unused_kprobe(ap); + ret = reuse_unused_kprobe(ap); + if (ret) + goto out; + } if (kprobe_gone(ap)) { /*