64-bit code with 32-bit pointers (-mx32) no longer working

[harristomy]

Windows Version

Microsoft Windows [Version 10.0.22631.5335]

WSL Version

2.5.7.0

Are you using WSL 1 or WSL 2?

• [x] WSL 2
• [ ] WSL 1

Kernel Version

6.6.87.1-1

Distro Version

Ubuntu 24.04

Other Software

No response

Repro Steps

Write basic C program that is compiled with the -mx32 flag.

Expected Behavior

C Application built with -mx32 flag with either GCC or Clang fails to execute.

Actual Behavior

Diagnostic Logs

No response

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[0xbadfca11]

Previously enabled x32 abi support has now been disabled. https://github.com/microsoft/WSL2-Linux-Kernel/blob/linux-msft-wsl-5.15.y/arch/x86/configs/config-wsl#L593 https://github.com/microsoft/WSL2-Linux-Kernel/blob/linux-msft-wsl-6.6.y/arch/x86/configs/config-wsl#L691

[harristomy]

Any idea why?

[benhillis]

@chessturo - can you please take a look?

[harristomy]

4d72cb5bb5d14e520500e84316a5b7e0f9e572cf was the commit that changed this, if it helps

[chessturo]

We're planning to fix this issue in the next kernel release. In the meantime, you can build a custom kernel with the config enabled as a workaround.

[harristomy]

Thanks @chessturo!

[harristomy]

Any idea why it was disabled for the previous kernel release?

[0xbadfca11]

Since the item name has changed, make olddefconfig has probably reverted it to "not set" that the default value.