From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stanislav Kinsbursky Subject: Re: [RFC PATCH v8 0/5] IPC: checkpoint/restore in userspace enhancements Date: Sat, 22 Dec 2012 00:46:08 +0400 Message-ID: <50D4CA90.60205@parallels.com> References: <20121024151555.5642.79086.stgit@localhost.localdomain> <20121218123601.113a29c0.akpm@linux-foundation.org> <50D28EC8.7000708@parallels.com> <20121220124751.d7ccbd8e.akpm@linux-foundation.org> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <20121220124751.d7ccbd8e.akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org> Sender: linux-api-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Andrew Morton Cc: serge.hallyn-Z7WLFzj8eWMS+FvcfC7Uqw@public.gmane.org, ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, xemul-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org, catalin.marinas-5wv7dgnIgG8@public.gmane.org, will.deacon-5wv7dgnIgG8@public.gmane.org, jmorris-gx6/JNMH7DfYtjvyW6yDsg@public.gmane.org, cmetcalf-kv+TWInifGbQT0dZR+AlfA@public.gmane.org, joe.korty-oXJCJecloQs@public.gmane.org, dhowells-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, dledford-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, viro-RmSDqhL/yNMiFSDQTTA3OLVCufUGDwFn@public.gmane.org, kosaki.motohiro-+CUm20s59erQFUHtdCDX3A@public.gmane.org, linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, serue-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org, tglx-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org, paulmck-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org, devel-GEFAQzZX7r8dnm+yROfE0A@public.gmane.org, mtk.manpages-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, Sasha Levin , Wu Fengguang List-Id: linux-api@vger.kernel.org 21.12.2012 00:47, Andrew Morton =D0=BF=D0=B8=D1=88=D0=B5=D1=82: > On Thu, 20 Dec 2012 08:06:32 +0400 > Stanislav Kinsbursky wrote: > >> 19.12.2012 00:36, Andrew Morton __________: >>> On Wed, 24 Oct 2012 19:34:51 +0400 >>> Stanislav Kinsbursky wrote: >>> >>>> This respin of the patch set was significantly reworked. Most part= of new API >>>> was replaced by sysctls (by one per messages, semaphores and share= d memory), >>>> allowing to preset desired id for next new IPC object. >>>> >>>> This patch set is aimed to provide additional functionality for al= l IPC >>>> objects, which is required for migration of these objects by user-= space >>>> checkpoint/restore utils (CRIU). >>>> >>>> The main problem here was impossibility to set up object id. This = patch set >>>> solves the problem by adding new sysctls for preset of desired id = for new IPC >>>> object. >>>> >>>> Another problem was to peek messages from queues without deleting = them. >>>> This was achived by introducing of new MSG_COPY flag for sys_msgrc= v(). If >>>> MSG_COPY flag is set, then msgtyp is interpreted as message number= =2E >>> According to my extensive records, Sasha hit a bug in >>> ipc-message-queue-copy-feature-introduced.patch and Fengguang found= a >>> bug in >>> ipc-message-queue-copy-feature-introduced-cleanup-do_msgrcv-aroung-= msg_copy-feature.patch >>> >>> It's not obvious (to me) that these things have been identified and >>> fixed. What's the status, please? >> Hello, Andrew. >> Fengguang's issue was solved by "ipc: simplify message copying" I se= nt you. >> But I can't find Sasha's issue. As I remember, there was some proble= m in >> early >> version of the patch set. But I believe its fixed now. > http://lkml.indiana.edu/hypermail/linux/kernel/1210.3/01710.html > > Subject: "ipc, msgqueue: NULL ptr deref in msgrcv" Ah, yes. Thanks. Hi found it in initial version of code, which was significantly changed= =20 (or cleaned and simplified) by further patch series. And I cant find out, how this can happen, because this patch he bisect=20 to do not modify the queue itself, while he found the problem in testms= g.