Commit 0919871a authored by Tony Luck's avatar Tony Luck Committed by Dan Williams
Browse files

acpi/nfit: Fix race accessing memdev in nfit_get_smbios_id() 



Possible race accessing memdev structures after dropping the
mutex. Dan Williams says this could race against another thread
that is doing:

 # echo "ACPI0012:00" > /sys/bus/acpi/drivers/nfit/unbind

Reported-by: default avatarJane Chu <jane.chu@oracle.com>
Fixes: 23222f8f ("acpi, nfit: Add function to look up nvdimm...")
Signed-off-by: default avatarTony Luck <tony.luck@intel.com>
Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
parent 1cb95e07

drivers/acpi/nfit/core.c

+4 −2
Original line number Diff line number Diff line
@@ -714,6 +714,7 @@ int nfit_get_smbios_id(u32 device_handle, u16 *flags) 
	struct acpi_nfit_memory_map *memdev;

	struct acpi_nfit_desc *acpi_desc;

	struct nfit_mem *nfit_mem;

	u16 physical_id;



	mutex_lock(&acpi_desc_lock);

	list_for_each_entry(acpi_desc, &acpi_descs, list) {
@@ -721,10 +722,11 @@ int nfit_get_smbios_id(u32 device_handle, u16 *flags) 
		list_for_each_entry(nfit_mem, &acpi_desc->dimms, list) {

			memdev = __to_nfit_memdev(nfit_mem);

			if (memdev->device_handle == device_handle) {

				*flags = memdev->flags;

				physical_id = memdev->physical_id;

				mutex_unlock(&acpi_desc->init_mutex);

				mutex_unlock(&acpi_desc_lock);

				*flags = memdev->flags;

				return memdev->physical_id;

				return physical_id;

			}

		}

		mutex_unlock(&acpi_desc->init_mutex);