Re: GC crashes

[Kenichi Handa <handa@m17n.org>]

In article <jwv8ylum1z2.fsf-monnier+emacs/devel@vor.iro.umontreal.ca>, Stefan Monnier <monnier@IRO.UMontreal.CA> writes:
>>  If the composition hash table is weak, GC can remove
>>  key-value pair from the table when a text that contains key
>>  as `composition' property is deleted (for instance by
>>  killing a buffer).

> I guess strictly speaking, the :weak arg should not be t but `key' so
> that only the key part is weak,

Does it make difference when the value part is always
integer?

> but that does not explain the crash.

No.

>>  The crash can be preproduced by this Emacs
>>      GNU Emacs 21.3.50.77 (i686-pc-linux-gnu, X toolkit, Xaw3d scroll bars)
>>  by doing this (of course by undoing my fix):

>>  C-u C-h t thai RET
>>  C-v (repeatedly until you reach the bottom)
>>  C-x k RET
>>  M-x garbage-collect RET
>>  C-u C-h t thai RET
>>  C-v (repeatedly)

>>  You'll encounter segfault before you reach the bottom.

> I don't get the crash (with an Emacs checked out two weeks ago from CVS).
> Maybe it's because I don't have the relevant fonts ?

Fonts are not relevant here.  Hmmm, I found sometimes I need
the above steps once to twice more to make segfault.

>>  This segfault always happens while marking a buffer that
>>  contains `composition' property (in the above case, it's
>>  TUTORIAL.th).  So, I doubted the composition hash table and
>>  made it strong, then the segfault disappeared.

> I suspect your fix just hides the underlying problem.

Perhaps, but I don't have a time to investigate this problem
further.  :-(

---
Ken'ichi HANDA
handa@m17n.org