Bug #74403 [Opn]: Sporadic FPM segfaults

Edit report at https://bugs.php.net/bug.php?id=74403&edit=1 ID: 74403 Updated by: requinix@php.net Reported by: tony2001@php.net -Summary: Sporadi +Summary: Sporadic FPM segfaults Status: Open Type: Bug Package: PCRE related Operating System: Linux PHP Version: 7.1.4RC1 Block user comment: N Private report: N New Comment: There have been a few php-fpm crashes reported over the last couple months. Can you tell if any of them are related to this? Previous Comments: ------------------------------------------------------------------------ [2017-04-10 11:09:09] tony2001@php.net The following patch has been added/updated: Patch Name: pcre-crashes-fix.diff Revision: 1491822546 URL: https://bugs.php.net/patch-display.php?bug=74403&patch=pcre-crashes-fix.diff&revision=1491822546 ------------------------------------------------------------------------ [2017-04-10 11:08:35] tony2001@php.net Description: ------------ Patch ebfd93f725eb9b9cfadbbde98047efe76f658da6 introduced an issue that is both hard to debug and reproduce. FPM processes start to crash in completely random places (mostly pointing to the executor code), all FPM children at once. Unfortunately, I don't have a reproduce case and I don't know of any reliable way to reproduce it, other than to start FPM on production server under a heavy load and leave it for a while. I've spent a lot of time debugging it and have found that the problem goes away as soon as I revert ebfd93f725eb9b9cfadbbde98047efe76f658da6. After looking at the patch closely, I've noticed that the patch changes one tricky part of the code managing refcount of the string stored in the cache. In the new version that part is gone and reverting this part of the patch fixes the issue, see attached patch. Test script: --------------- . Expected result: ---------------- No crashes. Actual result: -------------- Sporadic FPM segfaults. ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=74403&edit=1