Bug #81275 [Opn]: status page, contain bugus value in request duration sometimes

Edit report at https://bugs.php.net/bug.php?id=81275&edit=1 ID: 81275 User updated by: tsmtgdi at gmail dot com Reported by: tsmtgdi at gmail dot com Summary: status page, contain bugus value in request duration sometimes Status: Open Type: Bug Package: FPM related Operating System: Suse PHP Version: 8.1Git-2021-07-19 (Git) Block user comment: N Private report: N New Comment: After reviewing the code, I think the logic is correct, the problem is in some missing mutex or sync problem, for example I discovered having a single fpm process will never trigger the error. Also I had case of [pid] => 0 [state] => (null) [start time] => 0 [start since] => 1626722020 [requests] => 0 [request duration] => 51276947114 Which is... in theory impossible What I discovered is that, the proc = *scoreboard_p->procs[i]; Is not doing a correct copy, I have stack trace in which the proc is different from the scoreboard_p->procs[0] https://pastebin.com/Hxgwq1c1 I can say that "maybe" the operation is done outside of the mutex (in fact around line 196 you have a /* copy the scoreboard not to bother other processes */ scoreboard = *scoreboard_p; fpm_unlock(scoreboard_p->lock);) I will later try to use this copy. Previous Comments: ------------------------------------------------------------------------ [2021-07-19 18:24:19] tsmtgdi at gmail dot com I forget to add, I just compiled the php code (very easy! bravo!), and I will now try with the help of two coworker to do a patch. ------------------------------------------------------------------------ [2021-07-19 18:23:32] tsmtgdi at gmail dot com Description: ------------ When accessing the php-fpm status page (pm.status_path), when the process is in status "Reading headers", "Finishing" and "Starting", we have several cases in which the value request duration is bogus, we suspect is just reading an uninitialized memory location, we can even have value of 18446744073709551592 (almost all bit set)... Test script: --------------- Is quite easy, you have to poll with very high frequency the status page while doing many small request to increase the chance to find this bug. you can use siege or ab2 so simulate traffic on a dummy page (even empty is fine) and something like It should take 4/5 second at most on a free running loop... <?php while(true){ $json = file_get_contents("http://127.0.0.1/status.php?json&full"); $result = json_decode($json); $processes = $result->processes; foreach ($processes as $proc){ //a dummy page should take low time to be gen no ? if($proc->{"request duration"} > 1000000){ echo "impossible value found!"; print_r($proc); echo "\n"; die(); } } } ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=81275&edit=1