Comment 61 for bug 269651

Created an attachment (id=19760)
Serialise removals, and avoid using freed data caused by removals

Hi,

Further debugging revealed this issue with the previous patch.
While the removals were serialised each notify still contained
a reference to a watch, which will have been freed if a removal
was already triggered, causing a segfault.

I changed the code to also loop through watch->notifies when
removing the watch due to inotify, and NULL each notify->watch
reference, the code then checks this before trying to delete
the watch itself if asked to remove the notify.

In order to prevent other race conditions in this area I also
made the inotify code not pass a watch to emit_events_in_idle,
as the watch may get freed in the meantime. It instead passes
the wd and the emit loop looks up the watch, discarding the
event if the watch has been removed.

I did however leave in the code that checks for a removed watch
before doing anything with inotify, as I hoped that this would
just optimise this case.

Please review the attached patch for inclusion. I am going to
request testing of the patch in the Ubuntu bug, and if that
reveals no further problems seek an upload of the patch.

Thanks,

James