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=-6.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS 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 EF1B5C10F00 for ; Fri, 6 Mar 2020 17:43:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C06AF20656 for ; Fri, 6 Mar 2020 17:43:29 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="b4pGnJNQ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726178AbgCFRn3 (ORCPT ); Fri, 6 Mar 2020 12:43:29 -0500 Received: from us-smtp-2.mimecast.com ([207.211.31.81]:34343 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725873AbgCFRn3 (ORCPT ); Fri, 6 Mar 2020 12:43:29 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1583516608; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=hQDYGrSZez13kaLQWFtQ3x9F4gdNnjFBgu39A3ps7Ig=; b=b4pGnJNQrtjzwhCqRErII/mfsq4qz9k2p3BmhOnN9koFnXxPlAzSco4s9w0lTxG74iGFeH C2M5MASNQZqLYwXXn40hFqnMbY1spbQ+Dl0wxGCWPyPJO4a8zJ111id9jU8tqJw7i8DXqZ BFQtlISVvpQc9pNetBLHJt0UG4+mGCQ= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-171-YLIECvZuOtuVeYOipalFOg-1; Fri, 06 Mar 2020 12:43:26 -0500 X-MC-Unique: YLIECvZuOtuVeYOipalFOg-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 28D841937FC2; Fri, 6 Mar 2020 17:43:25 +0000 (UTC) Received: from shodan.usersys.redhat.com (unknown [10.43.17.65]) by smtp.corp.redhat.com (Postfix) with ESMTPS id EB4B67386E; Fri, 6 Mar 2020 17:43:24 +0000 (UTC) Received: by shodan.usersys.redhat.com (Postfix, from userid 1000) id 99E571C0183; Fri, 6 Mar 2020 18:43:23 +0100 (CET) From: Artem Savkov To: Steven Rostedt Cc: linux-kernel@vger.kernel.org, live-patching@vger.kernel.org, Artem Savkov Subject: [PATCH v2] ftrace: return first found result in lookup_rec() Date: Fri, 6 Mar 2020 18:43:17 +0100 Message-Id: <20200306174317.21699-1-asavkov@redhat.com> In-Reply-To: <20200306121246.5dac2573@gandalf.local.home> References: <20200306121246.5dac2573@gandalf.local.home> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 Content-Transfer-Encoding: quoted-printable Sender: live-patching-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: live-patching@vger.kernel.org It appears that ip ranges can overlap so. In that case lookup_rec() returns whatever results it got last even if it found nothing in last searched page. This breaks an obscure livepatch late module patching usecase: - load livepatch - load the patched module - unload livepatch - try to load livepatch again To fix this return from lookup_rec() as soon as it found the record containing searched-for ip. This used to be this way prior lookup_rec() introduction. v2: break instead of two returns Fixes: 7e16f581a817 ("ftrace: Separate out functionality from ftrace_loca= tion_range()") Signed-off-by: Artem Savkov --- kernel/trace/ftrace.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 3f7ee102868a..fd81c7de77a7 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -1547,6 +1547,8 @@ static struct dyn_ftrace *lookup_rec(unsigned long = start, unsigned long end) rec =3D bsearch(&key, pg->records, pg->index, sizeof(struct dyn_ftrace), ftrace_cmp_recs); + if (rec) + break; } return rec; } --=20 2.21.1