Memory Leak and Segfault (Exit Code 139) in Aws\ResultPaginator Due to Repeated Metrics Middleware Registration

[iromanko]

Describe the bug

Starting from version 3.336.0, the Aws\ResultPaginator class continuously adds a metrics middleware each time it is instantiated. This leads to:
• An increasing function call stack over time in long-running processes.
• High memory consumption due to repeated middleware registrations.
• In some cases, PHP crashes with exit code 139 (segmentation fault).

Regression Issue

• Select this option if this issue appears to be a regression.

Expected Behavior

The Aws\ResultPaginator class should not repeatedly add the metrics middleware on each instantiation. Middleware should be registered once per client lifecycle or have a mechanism to prevent redundant additions.

Current Behavior

Fatal error: Allowed memory size of 134217728 bytes exhausted (tried to allocate 2097152 bytes) in /srv/app/vendor/aws/aws-sdk-php/src/functions.php on line 67

Call Stack:
    0.0011     480264   1. {main}() /srv/app/reproducer.php:0
   10.3241  131880872   2. Aws\AwsClient->getIterator($name = 'Scan', $args = ['TableName' => 'test']) /srv/app/reproducer.php:13
   10.3243  131883568   3. Aws\ResultPaginator->search($expression = 'Items') /srv/app/vendor/aws/aws-sdk-php/src/AwsClientTrait.php:35

Reproduction Steps

Steps to reproduce the behavior:
1. Run a long-running script that continuously creates Aws\ResultPaginator instances.
2. Monitor memory usage and function call stack growth.
3. Eventually, PHP may crash with exit code 139.

$sdk = new Aws\Sdk([
    'region'  => 'us-east-2',
    'version' => 'latest',
]);

$dynamoDb = $sdk->createDynamoDb();

while (true) {
    $paginator = $dynamoDb->getIterator('Scan', ['TableName' => 'test']);
}

Possible Solution

A possible fix could involve checking if the middleware is already present before adding it again.

Additional Information/Context

Disabling the metrics middleware prevents the issue, confirming it as the root cause.

SDK version used

3.339.14

Environment details (Version of PHP (php -v)? OS name and version, etc.)

PHP 8.3.8

[yenfryherrerafeliz]

Hi @iromanko, sorry for the inconvenient. The metrics implementation was adding named middlewares, however, our middleware handler list does not validate if a middleware was already appended in order to append a new middleware, and hence adding the same middleware multiple times. I have created this patch in order to prevent this behavior when appending the metrics middleware.

Thank you!

[stobrien89]

Hi @iromanko,

I believe #3087 should fix this. Closing for now. Please let us know if you're still having issues after upgrading and testing.

[github-actions]

This issue is now closed. Comments on closed issues are hard for our team to see.
If you need more assistance, please open a new issue that references this one.

[iromanko]

@yenfryherrerafeliz @stobrien89 thanks for the quick fix! I’ve tested the update, and everything is working correctly now. Appreciate the fast response and support!