Re: [Qemu-devel] [PATCH] migration: fix small leaks

[Dr. David Alan Gilbert]

* Vladimir Sementsov-Ogievskiy (address@hidden) wrote:
> 28.12.2017 05:19, Peter Xu wrote:
> > On Wed, Dec 27, 2017 at 03:25:23PM +0300, Vladimir Sementsov-Ogievskiy 
> > wrote:
> > > Hi all!
> > > 
> > > Hmm, looks like leak is not fixed here: I've checked it while running 
> > > iotest
> > > 181, that
> > > migration_instance_finalize is not called.
> > > 
> > > If I understand correct, to call it we need unref current_migration object
> > > somewhere.
> > > 
> > > Or, may be I'm missing something..
> > I think you are right.
> > 
> > It does not matter much though since we don't dynamically allocate
> > migration object (there is only one and it lives forever).  Do you
> > want to post a patch?  I guess the safest place to unref it is at the
> > end of main() to make sure no one will be using it any more.
> > 
> > (Hmm, the incoming migration state is still static)
> > 
> > Thanks,
> 
> Ok, I'll send a patch.

Be very very careful that it doesn't crash in cases like quit in the main thread
while a migration is still running.

I have no problem with this object living forever and letting it just
die with exit().

Dave


> > 
> > > 01.08.2017 19:04, Marc-André Lureau wrote:
> > > > Spotted thanks to valgrind and tests/device-introspect-test:
> > > > 
> > > > ==11711== 1 bytes in 1 blocks are definitely lost in loss record 6 of 
> > > > 14,537
> > > > ==11711==    at 0x4C2EB6B: malloc (vg_replace_malloc.c:299)
> > > > ==11711==    by 0x1E0CDBD8: g_malloc (gmem.c:94)
> > > > ==11711==    by 0x1E0E696E: g_strdup (gstrfuncs.c:363)
> > > > ==11711==    by 0x695693: migration_instance_init (migration.c:2226)
> > > > ==11711==    by 0x717C4B: object_init_with_type (object.c:344)
> > > > ==11711==    by 0x717E80: object_initialize_with_type (object.c:375)
> > > > ==11711==    by 0x7182EB: object_new_with_type (object.c:483)
> > > > ==11711==    by 0x718328: object_new (object.c:493)
> > > > ==11711==    by 0x4B8A29: qmp_device_list_properties (qmp.c:542)
> > > > ==11711==    by 0x4A9561: qmp_marshal_device_list_properties 
> > > > (qmp-marshal.c:1425)
> > > > ==11711==    by 0x819D4A: do_qmp_dispatch (qmp-dispatch.c:104)
> > > > ==11711==    by 0x819E82: qmp_dispatch (qmp-dispatch.c:131)
> > > > 
> > > > Signed-off-by: Marc-André Lureau <address@hidden>
> > > > ---
> > > >    migration/migration.c | 10 ++++++++++
> > > >    1 file changed, 10 insertions(+)
> > > > 
> > > > diff --git a/migration/migration.c b/migration/migration.c
> > > > index 085c32c994..c3fe0ed9ca 100644
> > > > --- a/migration/migration.c
> > > > +++ b/migration/migration.c
> > > > @@ -2214,6 +2214,15 @@ static void migration_class_init(ObjectClass 
> > > > *klass, void *data)
> > > >        dc->props = migration_properties;
> > > >    }
> > > > +static void migration_instance_finalize(Object *obj)
> > > > +{
> > > > +    MigrationState *ms = MIGRATION_OBJ(obj);
> > > > +    MigrationParameters *params = &ms->parameters;
> > > > +
> > > > +    g_free(params->tls_hostname);
> > > > +    g_free(params->tls_creds);
> > > > +}
> > > > +
> > > >    static void migration_instance_init(Object *obj)
> > > >    {
> > > >        MigrationState *ms = MIGRATION_OBJ(obj);
> > > > @@ -2282,6 +2291,7 @@ static const TypeInfo migration_type = {
> > > >        .class_size = sizeof(MigrationClass),
> > > >        .instance_size = sizeof(MigrationState),
> > > >        .instance_init = migration_instance_init,
> > > > +    .instance_finalize = migration_instance_finalize,
> > > >    };
> > > >    static void register_migration_types(void)
> > > 
> > > -- 
> > > Best regards,
> > > Vladimir
> > > 
> > > 
> 
> 
> -- 
> Best regards,
> Vladimir
> 
--
Dr. David Alan Gilbert / address@hidden / Manchester, UK