On Wed, Jun 10, 2015 at 10:27:11 -0400, John Ferlan wrote:
>
>
> On 06/10/2015 09:42 AM, Jiri Denemark wrote:
> > QEMU will soon (patches are available on qemu-devel) get support for
> > migration events which will finally allow us to get rid of polling
> > query-migrate every 50ms. However, we first need to be able to wait for
> > all events related to migration (migration status changes, block job
> > events, async abort requests) at once. This series prepares the
> > infrastructure and uses it to switch all polling loops in migration code
> > to pthread_cond_wait.
> >
> > https://bugzilla.redhat.com/show_bug.cgi?id=1212077
> >
> > Version 3 (see individual patches for details):
> > - most of the series has been ACKed in v2
> > - "qemu: Use domain condition for synchronous block jobs" was split in 3
> > patches for easier review
> > - minor changes requested in v2 review
> >
> > Version 2 (see individual patches for details):
> > - rewritten using per-domain condition variable
> > - enahnced to fully support the migration events
>
> Just ran this through my Coverity checker - only one issue
>
> RESOURCE_LEAK in qemuMigrationRun:
>
> 4235 if (qemuMigrationCheckJobStatus(driver, vm,
> 4236 QEMU_ASYNC_JOB_MIGRATION_OUT) <
> 0)
>
> (4) Event if_end: End of if statement
>
> 4237 goto cancel;
> 4238
>
> (5) Event open_fn: Returning handle opened by "accept".
> (6) Event var_assign: Assigning: "fd" = handle returned from
> "accept(spec->dest.unix_socket.sock, __SOCKADDR_ARG({ .__sockaddr__ = NULL}),
> NULL)".
> (7) Event cond_false: Condition "(fd =
> accept(spec->dest.unix_socket.sock, __SOCKADDR_ARG({ .__sockaddr__ = NULL}),
> NULL)) < 0", taking false branch
> Also see events: [leaked_handle]
>
> 4239 while ((fd = accept(spec->dest.unix_socket.sock, NULL, NULL)) <
> 0) {
> 4240 if (errno == EAGAIN || errno == EINTR)
> 4241 continue;
Hmm, what an old and unused (except for some ancient QEMU versions) code
path :-) However, this code is only executed if spec->destType ==
MIGRATION_DEST_UNIX, which only happens in tunnelled migration path,
which also sets spec.fwdType = MIGRATION_FWD_STREAM.
...
> (28) Event cond_false: Condition "spec->fwdType !=
> MIGRATION_FWD_DIRECT", taking false branch
>
> 4289 if (spec->fwdType != MIGRATION_FWD_DIRECT) {
> 4290 if (iothread && qemuMigrationStopTunnel(iothread, ret < 0) < 0)
> 4291 ret = -1;
> 4292 VIR_FORCE_CLOSE(fd);
Which means "spec->fwdType != MIGRATION_FWD_DIRECT" will be true and fd
will be correctly closed.
Jirka
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