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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: 23222f8f8d ("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>
hifive-unleashed-5.1
Tony Luck 2019-01-11 14:46:37 -08:00 committed by Dan Williams
parent 1cb95e072e
commit 0919871ac3
1 changed files with 4 additions and 2 deletions
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6
drivers/acpi/nfit/core.c
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@ -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);