drm/radeon: fix use after free in ATRM bios reading code.

Fixes:
https://bugs.freedesktop.org/show_bug.cgi?id=45503

Reported-and-Debugged-by: mlambda@gmail.com
Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/drivers/gpu/drm/radeon/radeon_atpx_handler.c b/drivers/gpu/drm/radeon/radeon_atpx_handler.c
index 13ac63ba6075..98724fcb0088 100644
--- a/drivers/gpu/drm/radeon/radeon_atpx_handler.c
+++ b/drivers/gpu/drm/radeon/radeon_atpx_handler.c
@@ -59,8 +59,9 @@ static int radeon_atrm_call(acpi_handle atrm_handle, uint8_t *bios,
 
         obj = (union acpi_object *)buffer.pointer;
         memcpy(bios+offset, obj->buffer.pointer, obj->buffer.length);
+        len = obj->buffer.length;
         kfree(buffer.pointer);
-        return obj->buffer.length;
+        return len;
 }
 
 bool radeon_atrm_supported(struct pci_dev *pdev)