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authorLv Yunlong <lyl2019@mail.ustc.edu.cn>2021-04-26 14:43:40 +0200
committerJani Nikula <jani.nikula@intel.com>2021-05-12 19:52:40 +0200
commitea995218dddba171fecd05496c69617c5ef3c5b8 (patch)
treedc473a167df0912075be181dde23f0fe22cbcca8 /drivers
parentdrm/i915: Read C0DRB3/C1DRB3 as 16 bits again (diff)
downloadlinux-ea995218dddba171fecd05496c69617c5ef3c5b8.tar.xz
linux-ea995218dddba171fecd05496c69617c5ef3c5b8.zip
drm/i915/gt: Fix a double free in gen8_preallocate_top_level_pdp
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 <lyl2019@mail.ustc.edu.cn> Reviewed-by: Matthew Auld <matthew.auld@intel.com> Signed-off-by: Matthew Auld <matthew.auld@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20210426124340.4238-1-lyl2019@mail.ustc.edu.cn (cherry picked from commit ac69496fe65cca0611d5917b7d232730ff605bc7) Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/gpu/drm/i915/gt/gen8_ppgtt.c1
1 files changed, 0 insertions, 1 deletions
diff --git a/drivers/gpu/drm/i915/gt/gen8_ppgtt.c b/drivers/gpu/drm/i915/gt/gen8_ppgtt.c
index 176c19633412..74bf6fc8461f 100644
--- a/drivers/gpu/drm/i915/gt/gen8_ppgtt.c
+++ b/drivers/gpu/drm/i915/gt/gen8_ppgtt.c
@@ -641,7 +641,6 @@ static int gen8_preallocate_top_level_pdp(struct i915_ppgtt *ppgtt)
err = pin_pt_dma(vm, pde->pt.base);
if (err) {
- i915_gem_object_put(pde->pt.base);
free_pd(vm, pde);
return err;
}