From owner-freebsd-net@FreeBSD.ORG Wed Feb 4 13:52:05 2015 Return-Path: Delivered-To: freebsd-net@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id BF139F08 for ; Wed, 4 Feb 2015 13:52:05 +0000 (UTC) Received: from phabric-backend.isc.freebsd.org (phabric-backend.isc.freebsd.org [IPv6:2001:4f8:3:ffe0:406a:0:50:2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 7AB1295A for ; Wed, 4 Feb 2015 13:52:05 +0000 (UTC) Received: from phabric-backend.isc.freebsd.org (phabric-backend.isc.freebsd.org [127.0.1.5]) by phabric-backend.isc.freebsd.org (8.14.9/8.14.9) with ESMTP id t14Dq5f3041686 for ; Wed, 4 Feb 2015 13:52:05 GMT (envelope-from root@phabric-backend.isc.freebsd.org) Received: (from root@localhost) by phabric-backend.isc.freebsd.org (8.14.9/8.14.9/Submit) id t14Dq5Jp041685; Wed, 4 Feb 2015 13:52:05 GMT (envelope-from root) Date: Wed, 4 Feb 2015 13:52:05 +0000 To: freebsd-net@freebsd.org From: "rrs (Randall Stewart)" Subject: [Differential] [Commented On] D1711: Changes to the callout code to restore active semantics and also add a test-framework and test to validate thecallout code (and potentially for use by other tests). Message-ID: <4ecb6f65254e3bbc357bb3033f41a914@localhost.localdomain> X-Priority: 3 Thread-Topic: D1711: Changes to the callout code to restore active semantics and also add a test-framework and test to validate the callout code (and potentially for use by other tests). X-Herald-Rules: none X-Phabricator-To: X-Phabricator-To: X-Phabricator-To: X-Phabricator-To: X-Phabricator-To: X-Phabricator-To: X-Phabricator-To: X-Phabricator-To: X-Phabricator-To: X-Phabricator-To: X-Phabricator-Cc: X-Phabricator-Cc: X-Phabricator-Cc: X-Phabricator-Cc: X-Phabricator-Cc: X-Phabricator-Cc: X-Phabricator-Cc: X-Phabricator-Cc: X-Phabricator-Cc: In-Reply-To: References: Thread-Index: Y2JjMTcyODJkYzgxM2NkZDFjY2RhOGRmMTlkIFTSJAU= X-Phabricator-Sent-This-Message: Yes X-Mail-Transport-Agent: MetaMTA X-Auto-Response-Suppress: All X-Phabricator-Mail-Tags: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset="utf-8" X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 04 Feb 2015 13:52:05 -0000 rrs added a comment. Julian: The point is *exactly* that, the callout *has* a reference.. and now that the table is being flushed if the callout_stop returns 1 it thinks the callout has been stopped, which it has, which means it will not run and release its reference. Thus the lowering of the reference count on the return true from the stop. But the issue is the lock used is part of what the thing will free. I have looked through all callout_stops and only the lle code (in three forms) does this. I think the right fix here is to just go ahead and change the callout_init used to one with the MPSAFE flag. When the callout runs all it does is drop the lock and release the reference which causes the free in theory... So I think with a simple change to the init function this problem does not happen. REVISION DETAIL https://reviews.freebsd.org/D1711 To: rrs, gnn, rwatson, lstewart, jhb, kostikbel, hselasky, adrian, imp, sbruno Cc: julian, hiren, jhb, kostikbel, emaste, delphij, neel, erj, freebsd-net