Den 2011-04-18 21:23 skrev Peter Rosin:
> Den 2011-04-18 17:28 skrev Christopher Faylor:
>> On Mon, Apr 18, 2011 at 11:24:41AM -0400, Christopher Faylor wrote:
>>> On Mon, Apr 18, 2011 at 04:32:10PM +0200, Peter Rosin wrote:
>>>> Den 2011-04-18 14:23 skrev Peter Rosin:
>>>>> Den 2011-04-18 13:43 skrev Peter Rosin:
>>>>>> Hi!
>>>>>>
>>>>>> Using the following STC, I'm seeing what appears to be a memory
>>>>>> leak in select(2).
>>>>>>
>>>>> ----------------8<---(selectleak.c)---------
>>>>> #include <sys/time.h>
>>>>> #include <fcntl.h>
>>>>>
>>>>> int
>>>>> main(void)
>>>>> {
>>>>> fd_set fdset;
>>>>>
>>>>> long flags = fcntl(0, F_GETFL);
>>>>> fcntl(0, F_SETFL, flags | O_NONBLOCK);
>>>>>
>>>>> for (;;) {
>>>>> int res;
>>>>> char buf[20];
>>>>>
>>>>> FD_ZERO(&fdset);
>>>>> FD_SET(0, &fdset);
>>>>> res = select(1, &fdset, NULL, NULL, NULL);
>>>>> if (!res)
>>>>> continue;
>>>>> if (res < 0)
>>>>> return 1;
>>>>> res = read(0, buf, sizeof(buf));
>>>>> if (!res)
>>>>> break;
>>>>> if (res < 0)
>>>>> return 1;
>>>>> }
>>>>>
>>>>> return 0;
>>>>> }
>>>>> ----------------8<--------------------------
>>>>
>>>> Ok, I'm taking a wild swing at this, and my guess is that the call
>>>> sel.cleanup () in cygwin_select prematurely zeros out the cleanup
>>>> member of the select_record. The call to sel.poll () then adds
>>>> "stuff" to the select_record that really should have been cleaned
>>>> up, but isn't since cleanup has already been executed and then
>>>> zapped (by select_stuff::cleanup).
>>>>
>>>> But what do I know?
>>>
>>> How does sel.poll add "stuff" that should be cleaned up? That function
>>> only looks for bits to set.
>
> I shouldn't have included the strace, and I shouldn't have guessed about
> the cause of the problem without verifying my claims. Sorry about that.
> But for the record the included strace snippet is reoccurring like that
> many many times (the address of the allocation that isn't freed is
> moving). Further evidence; the STC leaks 1 MB every 3 seconds on my
> computer, that just can't be right.
Back with a patch this time. Fixes it for me...
Cheers,
Peter
2011-04-19 Peter Rosin <p...@lysator.liu.se>
* select.cc (pipe_cleanup): Don't leak a select_pipe_info when a
thread turned out not to be needed.
Index: select.cc
===================================================================
RCS file: /cvs/src/src/winsup/cygwin/select.cc,v
retrieving revision 1.163
diff -u -r1.163 select.cc
--- select.cc 4 Apr 2011 12:23:36 -0000 1.163
+++ select.cc 19 Apr 2011 21:25:44 -0000
@@ -644,13 +644,15 @@
pipe_cleanup (select_record *, select_stuff *stuff)
{
select_pipe_info *pi = (select_pipe_info *) stuff->device_specific_pipe;
- if (pi && pi->thread)
+ if (!pi)
+ return;
+ if (pi->thread)
{
pi->stop_thread = true;
pi->thread->detach ();
- delete pi;
- stuff->device_specific_pipe = NULL;
}
+ delete pi;
+ stuff->device_specific_pipe = NULL;
}
int
--
Problem reports: http://cygwin.com/problems.html
FAQ: http://cygwin.com/faq/
Documentation: http://cygwin.com/docs.html
Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple
