The code tries various methods for retreiving the BIOS data. However it doesn't clear the bios->data pointer between the iterations.
In some cases, the shadow() method will fail and not update bios->data at all, which will cause us to "score" the old data and incorrectly attribute that score to the new method. This can cause double frees later when disposing of the unused data.
Additionally, we were not freeing the data for methods that fail the score test (we only freed when a "best" is superseeded, not when the new method has a lower score than the exising "best"). Fix that as well.
Signed-off-by: Benjamin Herrenschmidt benh@kernel.crashing.org ---
This was found by code inspection while chasing a different bug, I do not hit the problem path on my machine.
drivers/gpu/drm/nouveau/nouveau_bios.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/nouveau/nouveau_bios.c b/drivers/gpu/drm/nouveau/nouveau_bios.c index 80963d0..1947d61 100644 --- a/drivers/gpu/drm/nouveau/nouveau_bios.c +++ b/drivers/gpu/drm/nouveau/nouveau_bios.c @@ -273,6 +273,7 @@ bios_shadow(struct drm_device *dev) mthd->score = score_vbios(bios, mthd->rw); mthd->size = bios->length; mthd->data = bios->data; + bios->data = NULL; } while (mthd->score != 3 && (++mthd)->shadow);
mthd = shadow_methods; @@ -281,7 +282,8 @@ bios_shadow(struct drm_device *dev) if (mthd->score > best->score) { kfree(best->data); best = mthd; - } + } else + kfree(mthd->data); } while ((++mthd)->shadow);
if (best->score) {