From a1ccb4adc6c879bdb59197f78172ae02ed356bc5 Mon Sep 17 00:00:00 2001 From: Tony Luck Date: Sun, 10 Feb 2019 20:46:38 +0800 Subject: [PATCH] acpi/nfit: Fix race accessing memdev in nfit_get_smbios_id() mainline inclusion from mainline-5.0 commit 0919871ac37f category: bugfix bugzilla: 7088 CVE: NA ------------------------------------------------- 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 Fixes: 23222f8f8dce ("acpi, nfit: Add function to look up nvdimm...") Signed-off-by: Tony Luck Signed-off-by: Dan Williams Signed-off-by: Hanjun Guo Reviewed-by: Xiongfeng Wang Signed-off-by: Yang Yingliang --- drivers/acpi/nfit/core.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/acpi/nfit/core.c b/drivers/acpi/nfit/core.c index ea59c01ce8db..f530d3541242 100644 --- a/drivers/acpi/nfit/core.c +++ b/drivers/acpi/nfit/core.c @@ -719,6 +719,7 @@ 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) { @@ -726,10 +727,11 @@ 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); -- GitLab