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=-3.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_PASS,T_DKIMWL_WL_HIGH,USER_AGENT_GIT 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 9DAE3C4321D for ; Tue, 21 Aug 2018 09:39:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 59118208C2 for ; Tue, 21 Aug 2018 09:39:55 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="JwR4zEW9" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 59118208C2 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org 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 S1726937AbeHUM7S (ORCPT ); Tue, 21 Aug 2018 08:59:18 -0400 Received: from mail.kernel.org ([198.145.29.99]:53196 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726584AbeHUM7R (ORCPT ); Tue, 21 Aug 2018 08:59:17 -0400 Received: from localhost.localdomain (NE2965lan1.rev.em-net.ne.jp [210.141.244.193]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id C2789208C2; Tue, 21 Aug 2018 09:39:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1534844392; bh=b70k6hylNV4gTFKNqqCQWGr6hs4NFyt8sFzYt9QXHYw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=JwR4zEW9VA2o+Q91qit3FehzUAFt/9IAis0RgftfO0egDrEyPitvo83+RZZjJZSli A2r1Cn98rA4EjwMhCTbUpwSb7HyZLRTSEoJ5iLapEanUAIDnyuyOPt7AmQScFkSX3r mhvvK27LC9h1P6dCfeRzDc8MICP/eDzAp07kuH4o= From: Masami Hiramatsu To: Ingo Molnar Cc: "Naveen N . Rao" , Anil S Keshavamurthy , "David S . Miller" , Masami Hiramatsu , linux-kernel@vger.kernel.org Subject: [PATCH -tip 4/5] kprobes: Return error if fail to reuse kprobe instead of BUG_ON Date: Tue, 21 Aug 2018 18:39:29 +0900 Message-Id: <153484436978.5385.10806549496148012761.stgit@devbox> X-Mailer: git-send-email 2.13.6 In-Reply-To: <153484425558.5385.1484910606397784412.stgit@devbox> References: <153484425558.5385.1484910606397784412.stgit@devbox> 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 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 --- 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)) { /*