Re: GLib may busy loop on invalid file descriptors

[Frediano Ziglio <fziglio redhat com>]

> Hi,
>
> I ran into an issue the other day where abrtd was polling an invalid
> file descriptor. Obviously, there must be a bug in abrtd which closed
> the wrong FD even though it was still registered with the mainloop
> using g_io_channel_unix_new and g_io_add_watch. However, the failure
> mode of GLib to simply busy loop seems quite bad.
>
> Should g_io_unix_check maybe react to (G_IO_HUP | G_IO_ERR | G_IO_NVAL)
> in a way that results in an error and the removal of the source? That
> is, effectively run a fallback handler application is watching these
> error conditions.
>
> A viable solution might be:
>  * Return TRUE from g_io_unix_check by always checking for the errors
>  * Test again in g_io_unix_dispatch but log an error and return FALSE
>    if none of the requested conditions match.
>
> Thoughts?
>
> Benjamin
>
> PS: https://github.com/abrt/abrt/issues/1280 has some info on the
> specific issue.

The problem is similar to a double free. In that case I would personally
abort the program. If GLib really care about security trying to recovery
is a bad idea.

Frediano