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| author | Dan Williams <dan.j.williams@intel.com> | 2023-02-14 02:01:05 +0100 |
|---|---|---|
| committer | Dan Williams <dan.j.williams@intel.com> | 2023-02-14 02:01:05 +0100 |
| commit | f57aec443c24d2e8e1f3b5b4856aea12ddda4254 (patch) | |
| tree | 30ec06e53a5872ea266960d87dacdc6bfe44ce39 /drivers/cxl | |
| parent | Merge branch 'for-6.3/cxl-ram-region' into cxl/next (diff) | |
| download | linux-f57aec443c24d2e8e1f3b5b4856aea12ddda4254.tar.xz linux-f57aec443c24d2e8e1f3b5b4856aea12ddda4254.zip | |
cxl/pmem: Fix nvdimm registration races
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>
Diffstat (limited to 'drivers/cxl')
| -rw-r--r-- | drivers/cxl/pmem.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/drivers/cxl/pmem.c b/drivers/cxl/pmem.c index 08bbbac9a6d0..71cfa1fdf902 100644 --- a/drivers/cxl/pmem.c +++ b/drivers/cxl/pmem.c @@ -76,6 +76,7 @@ static int cxl_nvdimm_probe(struct device *dev) return rc; set_bit(NDD_LABELING, &flags); + set_bit(NDD_REGISTER_SYNC, &flags); set_bit(ND_CMD_GET_CONFIG_SIZE, &cmd_mask); set_bit(ND_CMD_GET_CONFIG_DATA, &cmd_mask); set_bit(ND_CMD_SET_CONFIG_DATA, &cmd_mask); |