korg/linux
0
0
Fork 0
mirror of https://mirrors.bfsu.edu.cn/git/linux.git synced 2024-11-11 20:48:49 +08:00
Code Issues Packages Projects Releases Wiki Activity

cxl/pmem: Fix nvdimm registration races

Browse Source 
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: 21083f5152 ("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>
This commit is contained in:
Dan Williams 2023-02-13 17:01:05 -08:00
parent b8b9ffced0
commit f57aec443c
5 changed files with 25 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
drivers/cxl/pmem.c
View File

@ -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);

19
drivers/nvdimm/bus.c
View File

@ -508,7 +508,7 @@ static void nd_async_device_unregister(void *d, async_cookie_t cookie)
put_device(dev);
}
void nd_device_register(struct device *dev)
static void __nd_device_register(struct device *dev, bool sync)
{
if (!dev)
return;
@ -531,11 +531,24 @@ void nd_device_register(struct device *dev)
}
get_device(dev);
async_schedule_dev_domain(nd_async_device_register, dev,
&nd_async_domain);
if (sync)
nd_async_device_register(dev, 0);
else
async_schedule_dev_domain(nd_async_device_register, dev,
&nd_async_domain);
}
void nd_device_register(struct device *dev)
{
__nd_device_register(dev, false);
}
EXPORT_SYMBOL(nd_device_register);
void nd_device_register_sync(struct device *dev)
{
__nd_device_register(dev, true);
}
void nd_device_unregister(struct device *dev, enum nd_async_mode mode)
{
bool killed;

5
drivers/nvdimm/dimm_devs.c
View File

@ -624,7 +624,10 @@ struct nvdimm *__nvdimm_create(struct nvdimm_bus *nvdimm_bus,
nvdimm->sec.ext_flags = nvdimm_security_flags(nvdimm, NVDIMM_MASTER);
device_initialize(dev);
lockdep_set_class(&dev->mutex, &nvdimm_key);
nd_device_register(dev);
if (test_bit(NDD_REGISTER_SYNC, &flags))
nd_device_register_sync(dev);
else
nd_device_register(dev);
return nvdimm;
}

1
drivers/nvdimm/nd-core.h
View File

@ -107,6 +107,7 @@ int nvdimm_bus_create_ndctl(struct nvdimm_bus *nvdimm_bus);
void nvdimm_bus_destroy_ndctl(struct nvdimm_bus *nvdimm_bus);
void nd_synchronize(void);
void nd_device_register(struct device *dev);
void nd_device_register_sync(struct device *dev);
struct nd_label_id;
char *nd_label_gen_id(struct nd_label_id *label_id, const uuid_t *uuid,
u32 flags);

3
include/linux/libnvdimm.h
View File

@ -41,6 +41,9 @@ enum {
*/
NDD_INCOHERENT = 7,
/* 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,