diff options
| author | Mario Limonciello <mario.limonciello@amd.com> | 2024-10-11 12:23:15 -0500 |
|---|---|---|
| committer | Alex Deucher <alexander.deucher@amd.com> | 2024-10-22 18:08:12 -0400 |
| commit | bf58f03931fdcf7b3c45cb76ac13244477a60f44 (patch) | |
| tree | 08764e498c64086d3e626dc048e35b59ec781009 /drivers | |
| parent | 42f7652d3eb527d03665b09edac47f85fb600924 (diff) | |
| download | lwn-bf58f03931fdcf7b3c45cb76ac13244477a60f44.tar.gz lwn-bf58f03931fdcf7b3c45cb76ac13244477a60f44.zip | |
drm/amd: Guard against bad data for ATIF ACPI method
If a BIOS provides bad data in response to an ATIF method call
this causes a NULL pointer dereference in the caller.
```
? show_regs (arch/x86/kernel/dumpstack.c:478 (discriminator 1))
? __die (arch/x86/kernel/dumpstack.c:423 arch/x86/kernel/dumpstack.c:434)
? page_fault_oops (arch/x86/mm/fault.c:544 (discriminator 2) arch/x86/mm/fault.c:705 (discriminator 2))
? do_user_addr_fault (arch/x86/mm/fault.c:440 (discriminator 1) arch/x86/mm/fault.c:1232 (discriminator 1))
? acpi_ut_update_object_reference (drivers/acpi/acpica/utdelete.c:642)
? exc_page_fault (arch/x86/mm/fault.c:1542)
? asm_exc_page_fault (./arch/x86/include/asm/idtentry.h:623)
? amdgpu_atif_query_backlight_caps.constprop.0 (drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c:387 (discriminator 2)) amdgpu
? amdgpu_atif_query_backlight_caps.constprop.0 (drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c:386 (discriminator 1)) amdgpu
```
It has been encountered on at least one system, so guard for it.
Fixes: d38ceaf99ed0 ("drm/amdgpu: add core driver (v4)")
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit c9b7c809b89f24e9372a4e7f02d64c950b07fdee)
Cc: stable@vger.kernel.org
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c | 15 |
1 files changed, 12 insertions, 3 deletions
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c index f85ace0384d2..1f5a296f5ed2 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c @@ -147,6 +147,7 @@ static union acpi_object *amdgpu_atif_call(struct amdgpu_atif *atif, struct acpi_buffer *params) { acpi_status status; + union acpi_object *obj; union acpi_object atif_arg_elements[2]; struct acpi_object_list atif_arg; struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL }; @@ -169,16 +170,24 @@ static union acpi_object *amdgpu_atif_call(struct amdgpu_atif *atif, status = acpi_evaluate_object(atif->handle, NULL, &atif_arg, &buffer); + obj = (union acpi_object *)buffer.pointer; - /* Fail only if calling the method fails and ATIF is supported */ + /* Fail if calling the method fails and ATIF is supported */ if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) { DRM_DEBUG_DRIVER("failed to evaluate ATIF got %s\n", acpi_format_exception(status)); - kfree(buffer.pointer); + kfree(obj); return NULL; } - return buffer.pointer; + if (obj->type != ACPI_TYPE_BUFFER) { + DRM_DEBUG_DRIVER("bad object returned from ATIF: %d\n", + obj->type); + kfree(obj); + return NULL; + } + + return obj; } /** |