Repeated crash on Linux: "Error in curl_multi operation: Unrecoverable error in select/poll"

Development Platform & Builds
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1

The editor crashes every couple minutes with this error message. Here’s the full trace:

[2024.10.10-17.34.48:086][893]LogCore: Assertion failed: Code == CURLM_OK [File:./Developer/DerivedDataCache/Private/Http/CurlHttpClient.cpp] [Line: 562] 
Error in curl_multi operation: Unrecoverable error in select/poll
0x00007fd7f86f3133 libUnrealEditor-DerivedDataCache.so!UE::FCurlHttpConnectionPool::ThreadLoop() [/mnt/horde/++UE5/Sync/Engine/Source/./Developer/DerivedDataCache/Private/Http/CurlHttpClient.cpp:515]
0x00007fd801bdbc52 libUnrealEditor-Core.so!FThreadImpl::Run() [/mnt/horde/++UE5/Sync/Engine/Source/./Runtime/Core/Private/HAL/Thread.cpp:66]
0x00007fd801b96917 libUnrealEditor-Core.so!FRunnableThreadPThread::Run() [/mnt/horde/++UE5/Sync/Engine/Source/./Runtime/Core/Private/HAL/PThreadRunnableThread.cpp:25]
0x00007fd801adf8df libUnrealEditor-Core.so!FRunnableThreadPThread::_ThreadProc(void*) [/mnt/horde/++UE5/Sync/Engine/Source/Runtime/Core/Private/HAL/PThreadRunnableThread.h:187]
0x00007fd7f56b0732 libc.so.6!UnknownFunction(0x8c731)

Here, a similar issue in another program was alleviated by raising the limit on open files, but that hasn’t worked for me.

Anyone else get this issue, or have any ideas on how to solve it? It’s making development quite hard.

2

I’m having this exact same issue. Multiple projects, 5.4 or 5.5 Unreal engine version.

LoginId:f7d6b2828c304ba1aa6dd9bb012d65e1-000003e8

Assertion failed: Code == CURLM_OK [File:./Developer/DerivedDataCache/Private/Http/CurlHttpClient.cpp] [Line: 572] 
Error in curl_multi operation: Unrecoverable error in select/poll


libUnrealEditor-DerivedDataCache.so!UE::FCurlHttpConnectionPool::ThreadLoop() [/mnt/horde/++UE5/Sync/Engine/Source/./Developer/DerivedDataCache/Private/Http/CurlHttpClient.cpp:572]
libUnrealEditor-Core.so!FThreadImpl::Run() [/mnt/horde/++UE5/Sync/Engine/Source/Runtime/Core/Public/Templates/Function.h:470]
libUnrealEditor-Core.so!FRunnableThreadPThread::Run() [/mnt/horde/++UE5/Sync/Engine/Source/./Runtime/Core/Private/HAL/PThreadRunnableThread.cpp:25]
libUnrealEditor-Core.so!FRunnableThreadPThread::_ThreadProc(void*) [/mnt/horde/++UE5/Sync/Engine/Source/Runtime/Core/Private/HAL/PThreadRunnableThread.h:187]
libc.so.6!UnknownFunction(0x9439c)
libc.so.6!UnknownFunction(0x11949b)

Edit 1:
I’m downloading Unreal 5.5 from Github (the source) and I’m going to see if removing this specific check leads to any issues. Will update when I’ve finished.

Edit 2:
I downloaded the source and built from that. I edited the Unreal file CurlHttpClient.cpp inside the function FCurlHttpConnectionPool and commented out the line checkf(Code == CURLM_OK, TEXT("Error in curl_multi operation: %hs"), curl_multi_strerror(Code));

Then I re-ran the make command to build the engine.

Then it lets me load the world again. Not the right change but it does at least let me run it!

@StapledBattery - if this helps!

Edit 3:
The above works, and works better sometimes, but it causes any world partitions to go invisible other times.

I’ve had more luck with this link where you modify the Engines defaults: