Re: [PATCH 8/9] KVM: selftests: Add KVM syscall wrappers for pthread_{g,s}etaffinity_np()

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] KVM syscall wrappers for pthread functions produce misleading error messages on failure.
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--- Patch [8]: [PATCH 8/9] KVM: selftests: Add KVM syscall wrappers for pthread_{g,s}etaffinity_np() ---
commit 9fc7623d339b95135fb5ecb9685356bc8dff9829
Author: Sean Christopherson <[email protected]>

KVM: selftests: Add KVM syscall wrappers for pthread_{g,s}etaffinity_np()

This commit adds KVM wrappers for pthread_getaffinity_np() and 
pthread_setaffinity_np() to simplify selftest code. It removes the need 
to manually check for success or supply the size of cpu_set_t in the tests.

[ ... ]

> diff --git a/tools/testing/selftests/kvm/include/kvm_syscalls.h b/tools/testing/selftests/kvm/include/kvm_syscalls.h
> index 002b5a4e59eb2..3d82351bef92e 100644
> --- a/tools/testing/selftests/kvm/include/kvm_syscalls.h
> +++ b/tools/testing/selftests/kvm/include/kvm_syscalls.h
> @@ -97,6 +97,22 @@ __KVM_SYSCALL_DEFINE(ftruncate, 2, unsigned int, fd, off_t, length);
>  __KVM_SYSCALL_DEFINE(madvise, 3, void *, addr, size_t, length, int, advice);
>  __KVM_SYSCALL_DEFINE(sched_getaffinity, 3, pid_t, pid, size_t, cpusetsize, cpu_set_t *, mask);
>  
> +__KVM_SYSCALL_DEFINE(pthread_getaffinity_np, 3, pthread_t, thread,
> +		     size_t, cpusetsize, cpu_set_t *, cpuset);
> +__KVM_SYSCALL_DEFINE(pthread_setaffinity_np, 3, pthread_t, thread,
> +		     size_t, cpusetsize, const cpu_set_t *, cpuset);

[Severity: Medium]
Will these pthread wrappers print misleading error messages on failure?

The pthread_* functions return positive error codes directly on failure 
rather than returning -1 and setting errno. If __KVM_SYSCALL_DEFINE formats 
its failure messages assuming errno is set, failing to set affinity could 
result in printing a stale or unrelated error string (such as "Success") 
alongside the return code, which might impede debugging.

[ ... ]

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Sashiko AI review · https://sashiko.dev/#/patchset/[email protected]?part=8