[BUG] failed to read memory remote_address=0x64, errno=14

[vtsykun]

Hi! Awesome project.

I've noticed a strange bug when tried to profile memory leak in project that use Fibers

Describe the bug

I got memory access error in this place read = $this->ffi->process_vm_readv(...). The function process_vm_readv returns with EFAULT 14 (Bad address) error code. Obviously that the passed address 0x64 is invalid, because usually the heap allocated with addresses 0x7fffffffffff-0x7f0000000000

sudo ./reli inspector:memory --pretty-print -p 114889 > mem_t0.json -vvv

In MemoryReader.php line 92:
                                                                           
  [Reli\Lib\Process\MemoryReader\MemoryReaderException (14)]               
  failed to read memory. target_pid=114889, remote_address=0x64, errno=14  
                                                                           

Exception trace:
  at /opt/progs/reli-prof/src/Lib/Process/MemoryReader/MemoryReader.php:92
 Reli\Lib\Process\MemoryReader\MemoryReader->read() at /opt/progs/reli-prof/src/Lib/Process/Pointer/RemoteProcessDereferencer.php:42
 Reli\Lib\Process\Pointer\RemoteProcessDereferencer->deref() at /opt/progs/reli-prof/src/Lib/PhpInternals/Types/Zend/ZendClassEntry.php:238
 Reli\Lib\PhpInternals\Types\Zend\ZendClassEntry->getStaticPropertyIterator() at /opt/progs/reli-prof/src/Lib/PhpProcessReader/PhpMemoryReader/MemoryLocationsCollector.php:1598
 Reli\Lib\PhpProcessReader\PhpMemoryReader\MemoryLocationsCollector->collectClassDefinition() at /opt/progs/reli-prof/src/Lib/PhpProcessReader/PhpMemoryReader/MemoryLocationsCollector.php:1524
 Reli\Lib\PhpProcessReader\PhpMemoryReader\MemoryLocationsCollector->collectClassDefinitionPointer() at /opt/progs/reli-prof/src/Lib/PhpProcessReader/PhpMemoryReader/MemoryLocationsCollector.php:1494
 Reli\Lib\PhpProcessReader\PhpMemoryReader\MemoryLocationsCollector->collectClassTable() at /opt/progs/reli-prof/src/Lib/PhpProcessReader/PhpMemoryReader/MemoryLocationsCollector.php:364
 Reli\Lib\PhpProcessReader\PhpMemoryReader\MemoryLocationsCollector->collectAll() at /opt/progs/reli-prof/src/Command/Inspector/MemoryCommand.php:95
 Reli\Command\Inspector\MemoryCommand->execute() at /opt/progs/reli-prof/vendor/symfony/console/Command/Command.php:326
 Symfony\Component\Console\Command\Command->run() at /opt/progs/reli-prof/vendor/symfony/console/Application.php:1063
 Symfony\Component\Console\Application->doRunCommand() at /opt/progs/reli-prof/vendor/symfony/console/Application.php:320
 Symfony\Component\Console\Application->doRun() at /opt/progs/reli-prof/vendor/symfony/console/Application.php:174
 Symfony\Component\Console\Application->run() at /opt/progs/reli-prof/reli:56

To Reproduce

1. I am profiling this library https://github.com/danog/MadelineProto. Docs https://docs.madelineproto.xyz/docs/REQUIREMENTS.html

2. Create and run script

<?php declare(strict_types=1);

use danog\MadelineProto\EventHandler\Attributes\Handler;
use danog\MadelineProto\EventHandler\Message;
use danog\MadelineProto\Settings;

require __DIR__.'/vendor/autoload.php';

class Handler1 extends \danog\MadelineProto\SimpleEventHandler
{
    #[Handler]
    public function handleMessage(Message $message): void
    {
        if ($_ENV['APP_DEBUG'] ?? false) {
            $event = json_decode(json_encode($message), true);
            $msg = json_encode($event, 448);
            echo "MSG---> $msg \n";
        }
    }
}


$settings = new Settings();
$info = $settings->getAppInfo();
!empty($_ENV['APP_API_HASH'])  ? $info->setApiHash($_ENV['APP_API_HASH']) : null;
!empty($_ENV['APP_API_ID']) ? $info->setApiId((int)$_ENV['APP_API_ID']) : null;

Handler1::startAndLoop('session.madeline', $settings);

Expected behavior
no exception

Execution Environment

• OS: Ubuntu 22.04
• PHP: 8.1.26
• The version of Reli - master

Target Process

• PHP: 8.1.26

UPD

Also I tried to use php-meminfo. But this library is not dump variables from suspended Fibers stack

[sj-i]

@vtsykun
Hi, thanks for the good bug report!

Currently, I'm extremely busy, and don't have the bandwidth to look into this...

Apparently you have solved the problem you originally had with the modified version of php-meminfo. Brilliant job!.

Anyway, I'll take a closer look into this issue as soon as I can make the time.

to profile memory leak in project that use Fibers

FYI, also Reli doesn't support dumping the variables in suspended Fibers currently. As you know it is not too difficult, but I just don't have the time. We plan to support it in 0.12.0 or 0.13.0, the actual timeframe has not yet been decided though.