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

[Dave Jiang <dave.jiang@intel.com>]

On 3/30/26 2:12 PM, Koralahalli Channabasappa, Smita wrote:
> On 3/26/2026 10:28 PM, 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
>> ---
>>
>> This builds on Smita's series [1] pushed out to for-7.1/dax-hmem in
>> cxl.git [2].
>>
>> [1]: http://lore.kernel.org/20260322195343.206900-1-Smita.KoralahalliChannabasappa@amd.com
>> [2]: https://git.kernel.org/pub/scm/linux/kernel/git/cxl/cxl.git/log/?h=for-7.1/dax-hmem
>>
>> Dan Williams (9):
>>    cxl/region: Fix use-after-free from auto assembly failure
>>    dax/cxl: Fix HMEM dependencies
>>    cxl/region: Limit visibility of cxl_region_contains_resource()
>>    cxl/region: Constify cxl_region_resource_contains()
>>    dax/hmem: Reduce visibility of dax_cxl coordination symbols
>>    dax/hmem: Fix singleton confusion between dax_hmem_work and hmem
>>      devices
>>    dax/hmem: Parent dax_hmem devices
>>    tools/testing/cxl: Simulate auto-assembly failure
>>    tools/testing/cxl: Test dax_hmem takeover of CXL regions
>>
>>   drivers/dax/Kconfig                |   6 +-
>>   drivers/cxl/cxl.h                  |  11 ++-
>>   drivers/dax/bus.h                  |  15 +++-
>>   include/cxl/cxl.h                  |  15 ----
>>   tools/testing/cxl/test/mock.h      |   8 ++
>>   drivers/cxl/core/region.c          |  68 +++++++++++++++--
>>   drivers/dax/hmem/device.c          |  28 ++++---
>>   drivers/dax/hmem/hmem.c            | 115 +++++++++++++++--------------
>>   tools/testing/cxl/test/cxl.c       |  66 +++++++++++++++++
>>   tools/testing/cxl/test/hmem_test.c |  47 ++++++++++++
>>   tools/testing/cxl/test/mem.c       |   3 +
>>   tools/testing/cxl/test/mock.c      |  50 +++++++++++++
>>   tools/testing/cxl/Kbuild           |   7 ++
>>   tools/testing/cxl/test/Kbuild      |   1 +
>>   14 files changed, 344 insertions(+), 96 deletions(-)
>>   delete mode 100644 include/cxl/cxl.h
>>   create mode 100644 tools/testing/cxl/test/hmem_test.c
>>
>>
>> base-commit: 51d2fa02c0e4b3b23c4484f2af9b6d65c35471e8
> 
> I tested this series. Its working as expected for me. Thanks for the incremental.

Hi Smita. Can you provide a tested-by tag pls?

> 
> Thanks
> Smita
>