Re: [PATCH 5/9] KVM: selftests: Add KVM syscall wrapper for pthread_create()

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Low] Misleading error reporting when pthread_create fails due to reliance on errno.
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--- Patch [5]: [PATCH 5/9] KVM: selftests: Add KVM syscall wrapper for pthread_create() ---
commit c5c266b1e7b797f8b82c5a3cecf097ba6720b060
Author: Sean Christopherson <seanjc@google.com>

KVM: selftests: Add KVM syscall wrapper for pthread_create()

This commit adds a KVM wrapper for pthread_create() to eliminate manual
success assertions in selftests. It replaces direct calls to pthread_create()
with kvm_pthread_create() across multiple test files.

> diff --git a/tools/testing/selftests/kvm/include/kvm_syscalls.h b/tools/testing/selftests/kvm/include/kvm_syscalls.h
> --- a/tools/testing/selftests/kvm/include/kvm_syscalls.h
> +++ b/tools/testing/selftests/kvm/include/kvm_syscalls.h

[ ... ]

> @@ -96,6 +97,10 @@ __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);
>  
> +typedef void *(*pthread_fn_t)(void *);
> +__KVM_SYSCALL_DEFINE(pthread_create, 4, pthread_t *, thread,
> +		     const pthread_attr_t *, attr, pthread_fn_t, fn, void *, arg);

[Severity: Low]
Does this lead to misleading error messages on failure?

The __KVM_SYSCALL_DEFINE macro seems to assume the wrapped function sets errno
on failure, which gets printed when the test asserts via __KVM_SYSCALL_ERROR. 
However, pthread_create() returns its error code directly rather than setting
errno. 

If thread creation fails, it looks like the test framework might print a
misleading message containing "errno: 0 (Success)" alongside the actual
non-zero return code. Should this use a different wrapper or assert strategy
that handles direct error returns?

> +
>  #define kvm_free_fd(fd)		\
>  do {				\
>  	kvm_close(fd);		\

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Sashiko AI review · https://sashiko.dev/#/patchset/20260730191908.2084803-1-seanjc@google.com?part=5