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

[Mark Brown]

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:

> > 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)

> >   # # 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.
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