Re: [LTP] userfaultfd: Add tests for UFFDIO_RWPROTECT and UFFDIO_SET_MODE

[linuxtestproject.agent@gmail.com]

Hi Ricardo,

On 24 Oct 2026, Ricardo Branco wrote:
> userfaultfd: Add tests for UFFDIO_RWPROTECT and UFFDIO_SET_MODE

> +++ b/testcases/kernel/syscalls/userfaultfd/userfaultfd08.c
> +	CHECK_UFFD_FEATURE(UFFD_FEATURE_RWP);
> +	uffd = SAFE_USERFAULTFD(O_CLOEXEC | O_NONBLOCK, false);
> +++ b/testcases/kernel/syscalls/userfaultfd/userfaultfd09.c
> +	CHECK_UFFD_FEATURE(UFFD_FEATURE_RWP);
> +	CHECK_UFFD_FEATURE(UFFD_FEATURE_RWP_ASYNC);
> +	uffd = SAFE_USERFAULTFD(O_CLOEXEC | O_NONBLOCK, false);

Medium: With vm.unprivileged_userfaultfd=0 and no CAP_SYS_PTRACE, both
tests report TCONF even when RWP is supported, because CHECK_UFFD_FEATURE()
and run() request kernel-fault-capable descriptors.
These tests only need userspace faults; use UFFD_USER_MODE_ONLY or enable
the existing EPERM retry in both the feature probe and test descriptor
creation.

Verdict - Needs revision

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