[Openmcl-devel] Need advice to debug segfault when runningconcurrent selects in clsql/postgresql

[Paul Meurer]

Am 31.10.2013 um 10:05 schrieb gainsttime at yandex.ua:

> On Wed, 30 Oct 2013, Paul Meurer wrote:
> 
>> I did do several other tests:
>> 
>> The code runs without problems both in ACL 9.0-smp, and in SBCL (both 64 bit Linux, 16 cores).
>> 
>> Then I tried to build a minimal example that doesn't use any extra libraries, just plain CCL and a
>> very basic C lib, and I think I somehow succeeded.
>> 
>> Here is the C library:
>> 
>> ---
>> // threadtest.c
>> // Compilation:
>> // gcc -Bsymbolic -shared threadtest.c -fPIC -L/usr/local/lib -o threadtest.so;
>> #include <stdio.h>
>> 
>> char *getstring() { return "asdfasdfasdfasdfasdfasdfasdfasdf" ; }
>> ---
>> 
>> and here the Lisp code.
>> 
>> ---
>> (open-shared-library "threadtest.so")
>> 
>> (defun getstring () (%get-cstring (external-call "getstring" :address)))
>> 
>> (dotimes (i 16)
>> (process-run-function
>>  (format nil "getstring~a" i)
>>  (lambda (i)
>>    (let ((list ())
>>   (size 0))
>>      (dotimes (i 100000)
>> #-consing
>> (incf size (length (getstring)))
>> #+consing
>> (push (getstring) list))))
>>  i))
>> ---
>> 
>> Again, the equivalent code (using cffi) runs fine in Allegro, and crashes in CCL. It crashes
>> immediately with the consing variant, and only on the second or third run with the non- (or
>> less)-consing variant. The crashes are of the same type as with the Postgres lib.
>> 
>> You might object that my simple-minded library is not threaded. If this is a valid objection, I
>> will try to write a threaded lib with a dedicated thread/connection for each lisp process. (I still
>> have to learn how this is done.) Yet I am wondering why I don't see similar behavior in ACL and
>> SBCL.
>> 
>> - Paul
> 
> Does CFFI variant crash in CCL?

Yes. CFFI is in this case nothing more than a wrapper around the CCL FFI functions. I removed the CFFI dependency to make the code independent from 3rd party code.

- Paul

-- 
Paul

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.clozure.com/pipermail/openmcl-devel/attachments/20131031/faf95868/attachment.htm>