[Devel] [RFC PATCH v8 0/5] IPC: checkpoint/restore in userspace enhancements

[Andrew Morton]

On Thu, 20 Dec 2012 08:06:32 +0400
Stanislav Kinsbursky <skinsbursky at parallels.com> wrote:

> 19.12.2012 00:36, Andrew Morton __________:
> > On Wed, 24 Oct 2012 19:34:51 +0400
> > Stanislav Kinsbursky <skinsbursky at parallels.com> 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 shared memory),
> >> allowing to preset desired id for next new IPC object.
> >>
> >> This patch set is aimed to provide additional functionality for all 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_msgrcv(). If
> >> MSG_COPY flag is set, then msgtyp is interpreted as message number.
> > 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 sent you.
> But I can't find Sasha's issue. As I remember, there was some problem 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"