Bug #77647 [Opn]: preload: Access violation in zend_mm_shutdown

Edit report at https://bugs.php.net/bug.php?id=77647&edit=1 ID: 77647 Updated by: nikic@php.net Reported by: mberchtold at gmail dot com Summary: preload: Access violation in zend_mm_shutdown Status: Open Type: Bug Package: opcache Operating System: Windows 10 x64 PHP Version: master-Git-2019-02-21 (snap) Block user comment: N Private report: N New Comment: Support for opcache.protect_memory=1 on Windows has landed in the meantime, so it might be possible to produce a better trace now. (Assuming that ext/phar is not used, which is not compatible with memory protection right now.) Previous Comments: ------------------------------------------------------------------------ [2019-03-23 10:31:15] nikic@php.net Thanks for checking! Unfortunately it's hard to do anything here, as a segfault during memory manager shutdown just indicates that memory manager data structures were corrupted at some point, but doesn't really tell us where. This is the point where I'd usually suggest to set opcache.protect_memory=1, but after checking the code this functionality is currently implemented using mprotect() only and has no VirtualProtect() support, so it won't actually do anything on Windows. We should probably add that to make debugging opcache issues easier on Windows... ------------------------------------------------------------------------ [2019-03-23 01:04:58] mberchtold at gmail dot com The stack trace: > VCRUNTIME140.dll!memset_repmovs() Line 67 Unknown php8.dll!00007ffc60cabd45() Unknown php-cgi.exe!00007ff77d6a1763() Unknown php-cgi.exe!00007ff77d6a40f8() Unknown kernel32.dll!BaseThreadInitThunk() Unknown ntdll.dll!RtlUserThreadStart() Unknown But for some reason, the debug symbols (in the debug-pack) aren't matching the binaries. ------------------------------------------------------------------------ [2019-03-23 00:42:55] mberchtold at gmail dot com Yes, the issue still exists with the latest master build: Revision: r598175e (March 22 2019, 18:25:00) ------------------------------------------------------------------------ [2019-03-18 10:58:15] nikic@php.net Just want to check back if this issue still exists. A lot of preloading issues have been fixed since this bug report, so maybe the issue is already resolved? ------------------------------------------------------------------------ [2019-02-21 19:48:45] mberchtold at gmail dot com Description: ------------ With preloading (preloading of zend framework 3, others) enabled, visiting certain urls of the website crashes php-cgi.exe When preloading is disabled, or when no classes are preloaded it does not crash. php master: r82d6759 > php8.dll!zend_mm_shutdown(_zend_mm_heap * heap, int full, int silent) Line 2269 C [Inline Frame] php8.dll!shutdown_memory_manager(int) C php8.dll!php_module_startup(_sapi_module_struct * sf, _zend_module_entry * additional_modules, unsigned int num_additional_modules) Line 2405 C php-cgi.exe!php_cgi_startup(_sapi_module_struct * sapi_module) Line 973 C php-cgi.exe!main(int argc, char * * argv) Line 1921 C [Inline Frame] php-cgi.exe!invoke_main() Line 78 C++ php-cgi.exe!__scrt_common_main_seh() Line 288 C++ kernel32.dll!00007ff81f3b81f4() Unknown ntdll.dll!00007ff82174a251() Unknown zend_mm_shutdown ... Code: /* move all chunks except of the first one into the cache */ p = heap->main_chunk->next; while (p != heap->main_chunk) { ---> zend_mm_chunk *q = p->next; // p is null p->next = heap->cached_chunks; heap->cached_chunks = p; p = q; heap->chunks_count--; heap->cached_chunks_count++; } Locals: + heap 0x0000026899200040 {use_custom_heap=0x00000000 storage=0x0000000000000000 <NULL> size=0x0000000000000000 ...} _zend_mm_heap * + heap->main_chunk 0x0000026899200000 {heap=0x0000026899200040 {use_custom_heap=0x00000000 storage=0x0000000000000000 <NULL> ...} ...} _zend_mm_chunk * + heap->main_chunk->next 0x0000000000000000 <NULL> _zend_mm_chunk * + p 0x0000000000000000 <NULL> _zend_mm_chunk * For some reason, heap->main_chunk->next is NULL which looks unexpected (heap corruption?). Test script: --------------- I don't have a reproducible case other than that it always crashes when accessing a certain url on an internal website. Expected result: ---------------- no crash Actual result: -------------- Unhandled exception thrown: read access violation. ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=77647&edit=1