On Mon, 26 Apr 2021 at 13:44, Lv Yunlong <[email protected]> wrote: > > Our code analyzer reported a double free bug. > > In gen8_preallocate_top_level_pdp, pde and pde->pt.base are allocated > via alloc_pd(vm) with one reference. If pin_pt_dma() failed, pde->pt.base > is freed by i915_gem_object_put() with a reference dropped. Then free_pd > calls free_px() defined in intel_ppgtt.c, which calls i915_gem_object_put() > to put pde->pt.base again. > > As pde->pt.base is protected by refcount, so the second put will not free > pde->pt.base actually. But, maybe it is better to remove the first put? > > Fixes: 82adf901138cc ("drm/i915/gt: Shrink i915_page_directory's slab bucket") > Signed-off-by: Lv Yunlong <[email protected]>
Yes, it looks like this fixes a potential use-after-free. Thanks for the patch, Reviewed-by: Matthew Auld <[email protected]> Pushed to drm-intel-gt-next. _______________________________________________ dri-devel mailing list [email protected] https://lists.freedesktop.org/mailman/listinfo/dri-devel
