diff options
| author | Dan Williams | 2023-02-13 17:01:05 -0800 |
|---|---|---|
| committer | Greg Kroah-Hartman | 2023-03-10 09:34:20 +0100 |
| commit | a371788d4f4a7f59eecd22644331d599979fd283 (patch) | |
| tree | 834eec020a1ca22cd1786f87e19e6bc6ff4a2ddc /include | |
| parent | 05cbf6ddd9847c7b4f0662c048f195b09405a9d0 (diff) | |
cxl/pmem: Fix nvdimm registration races
commit f57aec443c24d2e8e1f3b5b4856aea12ddda4254 upstream.
A loop of the form:
while true; do modprobe cxl_pci; modprobe -r cxl_pci; done
...fails with the following crash signature:
BUG: kernel NULL pointer dereference, address: 0000000000000040
[..]
RIP: 0010:cxl_internal_send_cmd+0x5/0xb0 [cxl_core]
[..]
Call Trace:
<TASK>
cxl_pmem_ctl+0x121/0x240 [cxl_pmem]
nvdimm_get_config_data+0xd6/0x1a0 [libnvdimm]
nd_label_data_init+0x135/0x7e0 [libnvdimm]
nvdimm_probe+0xd6/0x1c0 [libnvdimm]
nvdimm_bus_probe+0x7a/0x1e0 [libnvdimm]
really_probe+0xde/0x380
__driver_probe_device+0x78/0x170
driver_probe_device+0x1f/0x90
__device_attach_driver+0x85/0x110
bus_for_each_drv+0x7d/0xc0
__device_attach+0xb4/0x1e0
bus_probe_device+0x9f/0xc0
device_add+0x445/0x9c0
nd_async_device_register+0xe/0x40 [libnvdimm]
async_run_entry_fn+0x30/0x130
...namely that the bottom half of async nvdimm device registration runs
after the CXL has already torn down the context that cxl_pmem_ctl()
needs. Unlike the ACPI NFIT case that benefits from launching multiple
nvdimm device registrations in parallel from those listed in the table,
CXL is already marked PROBE_PREFER_ASYNCHRONOUS. So provide for a
synchronous registration path to preclude this scenario.
Fixes: 21083f51521f ("cxl/pmem: Register 'pmem' / cxl_nvdimm devices")
Cc: <stable@vger.kernel.org>
Reported-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/libnvdimm.h | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/include/linux/libnvdimm.h b/include/linux/libnvdimm.h index c74acfa1a3fe..4e5f578025c4 100644 --- a/include/linux/libnvdimm.h +++ b/include/linux/libnvdimm.h @@ -36,6 +36,9 @@ enum { /* dimm supports namespace labels */ NDD_LABELING = 6, + /* dimm provider wants synchronous registration by __nvdimm_create() */ + NDD_REGISTER_SYNC = 8, + /* need to set a limit somewhere, but yes, this is likely overkill */ ND_IOCTL_MAX_BUFLEN = SZ_4M, ND_CMD_MAX_ELEM = 5, |