This is a note to let you know that I've just added the patch titled
drm/i915/gvt: fix double free bug in split_2MB_gtt_entry
to the 6.0-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
drm-i915-gvt-fix-double-free-bug-in-split_2mb_gtt_en.patch
and it can be found in the queue-6.0 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit b09de68e7ce03fe6f7cfadefbd2ace1d47475e6d
Author: Zheng Wang <zyytlz.wz@xxxxxxx>
Date: Fri Dec 30 00:56:41 2022 +0800
drm/i915/gvt: fix double free bug in split_2MB_gtt_entry
[ Upstream commit 4a61648af68f5ba4884f0e3b494ee1cabc4b6620 ]
If intel_gvt_dma_map_guest_page failed, it will call
ppgtt_invalidate_spt, which will finally free the spt.
But the caller function ppgtt_populate_spt_by_guest_entry
does not notice that, it will free spt again in its error
path.
Fix this by canceling the mapping of DMA address and freeing sub_spt.
Besides, leave the handle of spt destroy to caller function instead
of callee function when error occurs.
Fixes: b901b252b6cf ("drm/i915/gvt: Add 2M huge gtt support")
Signed-off-by: Zheng Wang <zyytlz.wz@xxxxxxx>
Reviewed-by: Zhenyu Wang <zhenyuw@xxxxxxxxxxxxxxx>
Signed-off-by: Zhenyu Wang <zhenyuw@xxxxxxxxxxxxxxx>
Link: http://patchwork.freedesktop.org/patch/msgid/20221229165641.1192455-1-zyytlz.wz@xxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/gpu/drm/i915/gvt/gtt.c b/drivers/gpu/drm/i915/gvt/gtt.c
index ce0eb03709c3..80c60754a5c1 100644
--- a/drivers/gpu/drm/i915/gvt/gtt.c
+++ b/drivers/gpu/drm/i915/gvt/gtt.c
@@ -1214,10 +1214,8 @@ static int split_2MB_gtt_entry(struct intel_vgpu *vgpu,
for_each_shadow_entry(sub_spt, &sub_se, sub_index) {
ret = intel_gvt_dma_map_guest_page(vgpu, start_gfn + sub_index,
PAGE_SIZE, &dma_addr);
- if (ret) {
- ppgtt_invalidate_spt(spt);
- return ret;
- }
+ if (ret)
+ goto err;
sub_se.val64 = se->val64;
/* Copy the PAT field from PDE. */
@@ -1236,6 +1234,17 @@ static int split_2MB_gtt_entry(struct intel_vgpu *vgpu,
ops->set_pfn(se, sub_spt->shadow_page.mfn);
ppgtt_set_shadow_entry(spt, se, index);
return 0;
+err:
+ /* Cancel the existing addess mappings of DMA addr. */
+ for_each_present_shadow_entry(sub_spt, &sub_se, sub_index) {
+ gvt_vdbg_mm("invalidate 4K entry\n");
+ ppgtt_invalidate_pte(sub_spt, &sub_se);
+ }
+ /* Release the new allocated spt. */
+ trace_spt_change(sub_spt->vgpu->id, "release", sub_spt,
+ sub_spt->guest_page.gfn, sub_spt->shadow_page.type);
+ ppgtt_free_spt(sub_spt);
+ return ret;
}
static int split_64KB_gtt_entry(struct intel_vgpu *vgpu,
