Re: question: python gc doesn't collect buffer allocated by read_memory()

[HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>]

From: Tom Tromey <tromey@redhat.com>
Subject: Re: question: python gc doesn't collect buffer allocated by read_memory()
Date: Wed, 28 Mar 2012 11:37:40 -0600

>>>>>> ">" == HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com> writes:
> 
>>> I suspect another objects allocated remain while not collected.
> 
> Thanks, you are correct.
> 
> I used valgrind --tool=massif to find the problem.
> 
> TRY_CATCH clears the cleanup chain, so making a cleanup in a TRY_CATCH
> and then trying to run or discard it outside the TRY_CATCH will not
> work; instead it leaks the cleanup.
> 
> I am checking in the appended patch.  It fixes both leaks.  Verified
> with massif.
> 
> Tom
> 
> 2012-03-28  Tom Tromey  <tromey@redhat.com>
> 
> 	* python/py-inferior.c (infpy_read_memory): Remove cleanups and
> 	explicitly free 'buffer' on exit paths.  Decref 'membuf_object'
> 	before returning.
> 

After applying this patch, I no longer see any memory leak.

Again, thanks for your help, Tom.

(gdb) shell cat ./testpro.py
import gdb
import gc

i = gdb.inferiors()[0]
buf = gdb.parse_and_eval('buf')

count = 100000
while count >= 0:
    i.read_memory(buf.address, buf.type.sizeof)
    count -= 1
gc.collect()
(gdb) shell ps aux | head -n 1
USER       PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND
(gdb) shell ps aux | grep gdb | grep -v grep
hat      28071  0.6  0.3  81964 12364 pts/0    S+   09:41   0:00 /media/pub/repos/gdb/gdb/gdb ./testpro ./core.27403
(gdb) source ./testpro.py
(gdb) shell ps aux | grep gdb | grep -v grep
hat      28071  2.3  0.3  81968 12500 pts/0    S+   09:41   0:00 /media/pub/repos/gdb/gdb/gdb ./testpro ./core.27403
(gdb) source ./testpro.py
(gdb) shell ps aux | grep gdb | grep -v grep
hat      28071  2.7  0.3  81968 12500 pts/0    S+   09:41   0:01 /media/pub/repos/gdb/gdb/gdb ./testpro ./core.27403
(gdb) source ./testpro.py
sh(gdb) shell ps aux | grep gdb | grep -v grep
hat      28071  2.9  0.3  81968 12500 pts/0    S+   09:41   0:02 /media/pub/repos/gdb/gdb/gdb ./testpro ./core.27403

Thanks.
HATAYAMA, Daisuke