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authorDan Williams <dan.j.williams@intel.com>2023-02-14 04:01:05 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2023-03-10 11:34:20 +0300
commita371788d4f4a7f59eecd22644331d599979fd283 (patch)
tree834eec020a1ca22cd1786f87e19e6bc6ff4a2ddc /drivers/cxl
parent05cbf6ddd9847c7b4f0662c048f195b09405a9d0 (diff)
downloadlinux-a371788d4f4a7f59eecd22644331d599979fd283.tar.xz
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 'drivers/cxl')
-rw-r--r--drivers/cxl/pmem.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/drivers/cxl/pmem.c b/drivers/cxl/pmem.c
index 4c627d67281a..1fca9848883d 100644
--- a/drivers/cxl/pmem.c
+++ b/drivers/cxl/pmem.c
@@ -75,6 +75,7 @@ static int cxl_nvdimm_probe(struct device *dev)
goto out;
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);