segfault after an "invalid read of size 8"

Hello, I have a script which throw a segfault, in cli with PHP 5.2.6 (I just recompiled it from source). I track the error with valgrind, and obtain this as a result : ==17069== Invalid read of size 8

==17069==    at 0x6CBCAC: _zend_mm_alloc_int (zend_alloc.c:1767)
==17069==    by 0x6CC1DF: _estrndup (zend_alloc.c:2422)
==17069==    by 0x6EFFDC: add_assoc_string_ex (zend_API.c:1038)
==17069==    by 0x567027: zif_posix_uname (posix.c:466)
==17069==    by 0x71E3AC: zend_do_fcall_common_helper_SPEC (zend_vm_execute.h:200)
==17069==    by 0x709983: execute (zend_vm_execute.h:92)
==17069==    by 0x6DA134: zend_call_function (zend_execute_API.c:1013)
==17069==    by 0x6DB1C5: call_user_function_ex (zend_execute_API.c:640)
==17069==    by 0x6DB241: call_user_function (zend_execute_API.c:613)
==17069==    by 0x627D1A: user_shutdown_function_call (basic_functions.c:5311)
==17069==    by 0x6F133A: zend_hash_apply (zend_hash.c:673)
==17069==    by 0x627FD5: php_call_shutdown_functions (basic_functions.c:5395)

==17069== Address 0x61 is not stack'd, malloc'd or (recently) free'd ==17069== ==17069== Process terminating with default action of signal 11 (SIGSEGV) ==17069== Access not within mapped region at address 0x61

==17069==    at 0x6CBCAC: _zend_mm_alloc_int (zend_alloc.c:1767)
==17069==    by 0x6CC1DF: _estrndup (zend_alloc.c:2422)
==17069==    by 0x6EFFDC: add_assoc_string_ex (zend_API.c:1038)
==17069==    by 0x567027: zif_posix_uname (posix.c:466)
==17069==    by 0x71E3AC: zend_do_fcall_common_helper_SPEC (zend_vm_execute.h:200)
==17069==    by 0x709983: execute (zend_vm_execute.h:92)
==17069==    by 0x6DA134: zend_call_function (zend_execute_API.c:1013)
==17069==    by 0x6DB1C5: call_user_function_ex (zend_execute_API.c:640)
==17069==    by 0x6DB241: call_user_function (zend_execute_API.c:613)
==17069==    by 0x627D1A: user_shutdown_function_call (basic_functions.c:5311)
==17069==    by 0x6F133A: zend_hash_apply (zend_hash.c:673)
==17069==    by 0x627FD5: php_call_shutdown_functions (basic_functions.c:5395)

==17069== ==17069== ERROR SUMMARY: 1 errors from 1 contexts (suppressed: 66 from 4) ==17069== malloc/free: in use at exit: 2,641,381 bytes in 12,114 blocks. ==17069== malloc/free: 13,138 allocs, 1,024 frees, 7,178,514 bytes allocated. ==17069== For counts of detected errors, rerun with: -v ==17069== searching for pointers to 12,114 not-freed blocks. ==17069== checked 2,442,920 bytes. ==17069== ==17069== LEAK SUMMARY:

==17069==    definitely lost: 292 bytes in 11 blocks.
==17069==      possibly lost: 0 bytes in 0 blocks.
==17069==    still reachable: 2,641,089 bytes in 12,103 blocks.
==17069==         suppressed: 0 bytes in 0 blocks.

==17069== Rerun with --leak-check=full to see details of leaked memory. Should I try to reduce the size of the PHP script (actually it use a framework) to can reproduce the problem ; or is this output of valgrind is enough ? Thanks, Olivier