cxl/mem: Fix no cxl_nvd during pmem region auto-assembling
When CXL subsystem is auto-assembling a pmem region during cxl
endpoint port probing, always hit below calltrace.
BUG: kernel NULL pointer dereference, address: 0000000000000078
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
RIP: 0010:cxl_pmem_region_probe+0x22e/0x360 [cxl_pmem]
Call Trace:
<TASK>
? __die+0x24/0x70
? page_fault_oops+0x82/0x160
? do_user_addr_fault+0x65/0x6b0
? exc_page_fault+0x7d/0x170
? asm_exc_page_fault+0x26/0x30
? cxl_pmem_region_probe+0x22e/0x360 [cxl_pmem]
? cxl_pmem_region_probe+0x1ac/0x360 [cxl_pmem]
cxl_bus_probe+0x1b/0x60 [cxl_core]
really_probe+0x173/0x410
? __pfx___device_attach_driver+0x10/0x10
__driver_probe_device+0x80/0x170
driver_probe_device+0x1e/0x90
__device_attach_driver+0x90/0x120
bus_for_each_drv+0x84/0xe0
__device_attach+0xbc/0x1f0
bus_probe_device+0x90/0xa0
device_add+0x51c/0x710
devm_cxl_add_pmem_region+0x1b5/0x380 [cxl_core]
cxl_bus_probe+0x1b/0x60 [cxl_core]
The cxl_nvd of the memdev needs to be available during the pmem region
probe. Currently the cxl_nvd is registered after the endpoint port probe.
The endpoint probe, in the case of autoassembly of regions, can cause a
pmem region probe requiring the not yet available cxl_nvd. Adjust the
sequence so this dependency is met.
This requires adding a port parameter to cxl_find_nvdimm_bridge() that
can be used to query the ancestor root port. The endpoint port is not
yet available, but will share a common ancestor with its parent, so
start the query from there instead.
Fixes: f17b558d6663 ("cxl/pmem: Refactor nvdimm device registration, delete the workqueue")
Co-developed-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Li Ming <ming4.li@intel.com>
Tested-by: Alison Schofield <alison.schofield@intel.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Alison Schofield <alison.schofield@intel.com>
Link: https://patch.msgid.link/20240612064423.2567625-1-ming4.li@intel.com
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
4 files changed
