Microsoft WSL2 kernel 6.18.58.1 enables taskstats, virtio-blk built-in, and Hyper-V race fix

Microsoft has published linux-msft-wsl-6.18.58.1, updating the WSL2 Linux kernel to stable upstream version 6.18.58. This release incorporates several configuration changes that affect I/O performance, networking diagnostics, and wireless testing capabilities within Windows Subsystem for Linux 2 environments. The kernel now builds virtio-blk directly into the image rather than as a module, and restores x86 memory-type range register (MTRR) and page attribute table (PAT) support that had been previously disabled. A race condition between Hyper-V channel offer and rescind operations has also been addressed.

The update enables CONFIG_TASKSTATS and its associated options for process accounting, reactivates raw socket diagnostics through CONFIG_INET_RAW_DIAG, and adds CONFIG_MAC80211_HWSIM support on x86 for Wi-Fi hardware simulation. Microsoft has dropped a previously carried local patch for a perf build issue since the fix has landed upstream. The kernel remains released under the GPLv2 license as a fork of the mainline Linux kernel with WSL-specific modifications.

Kernel configuration and Hyper-V changes in WSL2 6.18.58.1

• Built-in virtio-blk: CONFIG_VIRTIO_BLK is now compiled into the kernel image rather than loaded as a module, which should reduce boot latency and eliminate module-availability failures for WSL2's primary block device interface.
• Memory type controls restored: MTRR and PAT are reenabled on x86, restoring user-space and driver access to memory-type configuration for cacheability and write-combining settings on WSL2 virtual machines.
• Task statistics enabled: CONFIG_TASKSTATS and associated options are now active, allowing tools like delayacct and getdelays to report per-task delay accounting data for performance analysis.
• Networking diagnostics reenabled: CONFIG_INET_RAW_DIAG restores the raw socket diagnostic interface used by tools such as ss to inspect raw IP and ICMP socket states.
• Hyper-V channel race fix: The release includes a fix for a race condition between Hyper-V VMBus channel offer and rescind operations, which could previously lead to channel state corruption or guest hangs.
• Wireless hardware simulation: CONFIG_MAC80211_HWSIM is enabled on x86, supporting software-defined Wi-Fi testing without physical hardware—useful for CI pipelines and network stack development.

Why it matters

For developers relying on WSL2 as their primary Linux environment, the built-in virtio-blk change removes a potential failure mode where block device support could fail to load, while restored MTRR and PAT support enables applications that depend on precise memory-type control such as GPU compute workloads and certain database engines. The taskstats and raw socket diagnostic additions improve observability parity with native Linux installations, making WSL2 more viable for systems performance engineering and network debugging workflows that previously required bare-metal or full-VM alternatives.