Re: [PATCH hotfix 6.12 v2 4/8] mm: resolve faulty mmap_region() error path behaviour

On Mon, Oct 28, 2024 at 06:57:25PM +0000, Lorenzo Stoakes wrote:

On Mon, Oct 28, 2024 at 06:29:36PM +0000, Mark Brown wrote:

quoted

any meaingful detail.  There's nothing particularly instructive in the
test logs, just plain reports that the tests failed:

On these memory allocation failures, could you tell me what errno is? Could you
check dmesg for anything strange?

Looks like this is mostly figured out already but JFTR:

As I said in the report there's nothing in the logs that I noticed,
anything there is that I've missed should be in the linked logs.  The
errnos I'm seeing are all:

# mmap(): Invalid argument (22)

quoted

  # # FAIL: mmap allocation

Interesting that it MAP_FAIL's though. This could be arch_validate_flags() being
moved around.

Could you do me a further favour then and try a kernel at this commit with:

	/* Allow architectures to sanity-check the vm_flags. */
	if (!arch_validate_flags(vm_flags))
		return -EINVAL;

In mmap_region() commented out?

Unsurprisingly given the above and the rest of the thread commenting out
that check causes the affected tests to pass, I didn't check for any
additional impacts.