Re: [PATCH] selftests/mm: fix FORCE_READ to read input value correctly.

On Tue, Aug 05, 2025 at 01:51:40PM -0400, Zi Yan wrote:

FORCE_READ() converts input value x to its pointer type then reads from address x. This is wrong. If x is a non-pointer, it would be caught it easily. But all FORCE_READ() callers are trying to read from a pointer and FORCE_READ() basically reads a pointer to a pointer instead of the original typed pointer. Almost no access violation was found, except the one from split_huge_page_test.

Fix it by implementing a simplified READ_ONCE() instead.

Fixes: 3f6bfd4789a0 ("selftests/mm: reuse FORCE_READ to replace "asm volatile("" : "+r" (XXX));"") Signed-off-by: Zi Yan ziy@nvidia.com

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Reviewed-by: Wei Yang richard.weiyang@gmail.com