Bug #81585 [NEW]: Memory leaks when creating short string arrrays

From: xtpd17 at gmail dot com Operating system: Windows 7 x64 PHP version: 8.0.12 Package: Reproducible crash Bug Type: Bug Bug description:Memory leaks when creating short string arrrays Description: ------------ (System: Win7x64, last Apache 2.4 x32, php x32) If your script creates array of small strings (not more than 2mb approx.) and gets all amount of available memory (memory_limit could be set or left "-1") and then stops on "Fatal error: Allowed memory exhausted", it doesn't free all memory, so size of httpd.exe remains huge. If you run this script several times, size of httpd.exe grows and grows, and at some point your _another_ "innocent" scripts fails when trying to alloc relatively small chunk of memory with "Out of memory" (though their limits were not exceeded). Steps to reproduce: reload script in browser several times until it fails. You'll see growing initial size of httpd, then fail. Notable things: - memory leaks only when we create small string (<2mb) - big (or not set) memory_limit spends memory faster - it looks like E_USER_ERROR also keeps memory busy (see commented strings in script) - at second run memory_get_usage(true) is close to zero, memory_get_usage() grows. - in fact we have "out of memory" error already in the second run, but I thought it would be more clear to have separate block to demonstrate leak. - feel free to experiment with settings values in script. TEST RESULTS (memory_limit = 1500M): FIRST RUN ---------------------- apache size: 16 mb, memory usage/real usage: 0/2 mb (0 items in array, 0 mb stored) apache size: 115 mb, memory usage/real usage: 98/100 mb (49 items in array, 98 mb stored) apache size: 213 mb, memory usage/real usage: 196/198 mb (98 items in array, 196 mb stored) ... Fatal error: Allowed memory size of 1572864000 bytes exhausted (tried to allocate 2093056 bytes) in test_leak.php on line 58 before crash: apache size: 1517 mb, memory usage/real usage: 1495/1500 mb (749 items in array, 1494 mb stored) --- SECOND RUN ------------------------------ apache size: 766 mb, memory usage/real usage: 0/2 mb (0 items in array, 0 mb stored) apache size: 766 mb, memory usage/real usage: 98/2 mb (49 items in array, 98 mb stored) apache size: 766 mb, memory usage/real usage: 196/2 mb (98 items in array, 196 mb stored) /// Fatal error: Out of memory (allocated 1113587712) (tried to allocate 2093056 bytes) in test_leak.php on line 58 (WE HAVE OUT OF MEMORY ERROR ALREADY AT THIS POINT) before crash: apache size: 1828 mb, memory usage/real usage: 1805/1062 mb (904 items in array, 1804 mb stored) --- THEN YOU GET 1297 mb of apache, then 1562... --- AND THEN... FAIL RUN ------------------------------------- apache size: 1694 mb, memory usage/real usage: 0/2 mb (0 items in array, 0 mb stored) apache overloaded (1694 mb), trying to alloc 200 mb Fatal error: Out of memory (allocated 2097152) (tried to allocate 209715224 bytes) in test_leak.php on line 51 before crash: apache size: 1694 mb, memory usage/real usage: 0/2 mb (0 items in array, 0 mb stored) Test script: --------------- https://pastebin.com/qh8hneTg -- Edit bug report at https://bugs.php.net/bug.php?id=81585&edit=1 -- Fix committed: https://bugs.php.net/fix.php?id=81585&r=fixed Fixed in release: https://bugs.php.net/fix.php?id=81585&r=alreadyfixed Need backtrace: https://bugs.php.net/fix.php?id=81585&r=needtrace Need Reproduce Script: https://bugs.php.net/fix.php?id=81585&r=needscript Try newer version: https://bugs.php.net/fix.php?id=81585&r=oldversion Not developer issue: https://bugs.php.net/fix.php?id=81585&r=support Expected behavior: https://bugs.php.net/fix.php?id=81585&r=notwrong Not enough info: https://bugs.php.net/fix.php?id=81585&r=notenoughinfo Submitted twice: https://bugs.php.net/fix.php?id=81585&r=submittedtwice register_globals: https://bugs.php.net/fix.php?id=81585&r=globals PHP version support discontinued: https://bugs.php.net/fix.php?id=81585&r=phptooold Daylight Savings: https://bugs.php.net/fix.php?id=81585&r=dst IIS Stability: https://bugs.php.net/fix.php?id=81585&r=isapi Install GNU Sed: https://bugs.php.net/fix.php?id=81585&r=gnused Floating point limitations: https://bugs.php.net/fix.php?id=81585&r=float No Zend Extensions: https://bugs.php.net/fix.php?id=81585&r=nozend MySQL Configuration Error: https://bugs.php.net/fix.php?id=81585&r=mysqlcfg