Re: [PATCH 0/9] dax/hmem: Add tests for the dax_hmem takeover capability

[Alison Schofield <alison.schofield@intel.com>]

On Thu, Mar 26, 2026 at 10:28:12PM -0700, Dan Williams wrote:
> Given all the cross subsystem dependencies needed to make this solution
> work, it needs to have a unit test to keep it functional.
> 
> On the path to writing that, several fixes fell out, but not to Smita's
> code, to mine. One use-after-free has been there since the original
> automatic region assembly code.
> 
> Here is a preview of the core of the test I will submit to the cxl-cli project:
> 
> ---
> modprobe cxl_mock_mem && modprobe cxl_test hmem_test=1
> 
> dax=$(find_dax_cxl)
> [[ "$dax" == "" ]] && err $LINENO
> dax=$(find_dax_hmem)
> [[ "$dax" != "" ]] && err $LINENO
> 
> unload
> 
> modprobe cxl_mock_mem && modprobe cxl_test fail_autoassemble hmem_test=1
> 
> dax=$(find_dax_cxl)
> [[ "$dax" != "" ]] && err $LINENO
> dax=$(find_dax_hmem)
> [[ "$dax" == "" ]] && err $LINENO
> 
> unload
> ---

I tested the new cxl-test patches following your commands above, and
all good. I'll ask about the race condition in that specific patch.

Tested this set on my real hardware too, confirmed this with Smita's
still passes my hotplug test cases.

snip