Re: [Libguestfs] virt-v2v valgrind errors in libosinfo
On Tuesday, 14 April 2020 15:16:49 CEST Richard W.M. Jones wrote:
On Tue, Apr 14, 2020 at 12:37:07PM +0200, Pino Toscano wrote:
> > Unfortunately we never free the database.
>
> Hm it is never freed? Wouldn't that result in actual leaks, since
> OsinfoDb_t_finalize (g_object_unref'ing the OsinfoDb) wouldn't be
> called?
I was thinking because of this:
https://github.com/libguestfs/virt-v2v/blob/cc294b7735dda467179b93a061d36...
which IIUC will allocate a DB (on first access) but it is never
released.
Oh this is interesting. I read in the documentation that custom blocks
have tag Custom_tag, which is higher than No_scan_tag, and thus they
aren't scanned by the GC. Indeed, even trying to Gc.finalize on the
object inside the lazy seems to have no effect.
I guess this is becase db is a top-level variable in Libosinfo_utils;
is there a way to change that behaviour somehow?
> > It could be that to express
> > this properly we'd need to expose (db, os) tuples to the OCaml garbage
> > collector.
>
> I thought about this, and according to knowledge this would be needed
> only if we want osinfo_os objects alive even when the osinfo_db gets
> "out of scope". Considering that the osinfo_db is kept basically
> statically this should be fine.
Right.
I don't believe the current code is wrong, my concern is more about
clearing up valgrind errors before the release.
Yup, it makes sense to do that.
--
Pino Toscano
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