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authorTony Luck <tony.luck@intel.com>2019-01-11 14:46:37 -0800
committerDan Williams <dan.j.williams@intel.com>2019-01-11 14:50:29 -0800
commit0919871ac37fdcf46c7657da0f1742efe096b399 (patch)
treed5cba0cc572ae3f4fd0ccd125e066043b71168a1 /drivers/acpi/nfit/core.c
parent1cb95e072ede5e3d6a54eefd520db21b45985896 (diff)
downloadlinux-0919871ac37fdcf46c7657da0f1742efe096b399.tar.gz
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: Jane Chu <jane.chu@oracle.com>
Fixes: 23222f8f8dce ("acpi, nfit: Add function to look up nvdimm...")
Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Diffstat (limited to 'drivers/acpi/nfit/core.c')
-rw-r--r--drivers/acpi/nfit/core.c6
1 files changed, 4 insertions, 2 deletions
diff --git a/drivers/acpi/nfit/core.c b/drivers/acpi/nfit/core.c
index 4ae953a5aebf..790691d9a982 100644
--- a/drivers/acpi/nfit/core.c
+++ b/drivers/acpi/nfit/core.c
@@ -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);