Fix minor issues found during code review

[chemwolf6922]

Summary of the Pull Request

This PR fixes a batch of minor issues found during AI code review.

src/linux/init/DnsServer.h:48
Change the data type from uint16_t to size_t to avoid a potential counter overflow on valid data. As the counter needs to hold at most 2 + 65535.

src/linux/init/init.cpp:2575
Drain the pending pids on SIGCHLD. Multiple SIGCHLD will only trigger the signalfd once if not processed fast enough:
https://man7.org/linux/man-pages/man7/signal.7.html

src/linux/init/util.cpp:3497
Fix a wrong condition. The old logic will mask most of the errors as EINVAL.

src/windows/common/WslCoreMessageQueue.h:174
Avoid a tight race condition between submit and cancel on m_tpHandle.

src/windows/service/exe/LxssUserSession.cpp:897
Avoid wrong context order. The order is asserted in debug builds. The old wrong MountDisk -> CreateVm context will crash the debug service.

src/windows/service/exe/LxssUserSession.cpp:980
Put the set owner after the revert. So, a failed set owner does not skip the revert.

src/windows/service/exe/WslCoreVm.cpp:1003
Fix a wrong revert logic. Where the disk will be reverted to offline if it was online.

src/windows/service/exe/WslCoreVm.cpp:2755
Block more invalid mount names.

PR Checklist

• Closes: Link to issue #xxx
• Communication: I've discussed this with core contributors already. If work hasn't been agreed, this work might be rejected
• Tests: Added/updated if needed and all pass
• Localization: All end user facing strings can be localized
• Dev docs: Added/updated if needed
• Documentation updated: If checked, please file a pull request on our docs repo and link it here: #xxx

Detailed Description of the Pull Request / Additional comments

Validation Steps Performed

Add test:
MountTests::MountTests::SpecifyInvalidMountName

[Copilot]

Pull request overview

This PR addresses a set of small correctness and robustness issues across both the Linux init components and the Windows VM/service code paths, plus adds a regression test for invalid wsl --mount --name values.

Changes:

• Tighten validation and fix revert/cleanup logic around disk attach/mount and VHD move operations (Windows service).
• Improve robustness of Linux init execution and SIGCHLD handling (drain waitpid, fix exec-result read condition, avoid offset overflow).
• Add a Windows mount regression test for invalid mount names.

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
test/windows/MountTests.cpp	Adds a new test for invalid --mount --name inputs.
src/windows/service/exe/WslCoreVm.cpp	Fixes disk online revert behavior and blocks additional invalid mount names.
src/windows/service/exe/LxssUserSession.cpp	Fixes execution context ordering and ensures VHD revert is not skipped on ownership failure.
src/windows/common/WslCoreMessageQueue.h	Adjusts threadpool work submission placement to reduce a submit/cancel race.
src/linux/init/util.cpp	Fixes an incorrect condition when interpreting exec-status pipe reads.
src/linux/init/init.cpp	Drains pending SIGCHLD children to avoid missing coalesced signals.
src/linux/init/DnsServer.h	Changes request-offset type to avoid potential overflow for valid TCP DNS requests.

[Copilot]

Pull request overview

Copilot reviewed 7 out of 7 changed files in this pull request and generated 2 comments.

[Copilot]

Pull request overview

Copilot reviewed 7 out of 7 changed files in this pull request and generated no new comments.