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 4.19-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_entry.patch and it can be found in the queue-4.19 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 4a61648af68f5ba4884f0e3b494ee1cabc4b6620 Mon Sep 17 00:00:00 2001 From: Zheng Wang <zyytlz.wz@xxxxxxx> Date: Fri, 30 Dec 2022 00:56:41 +0800 Subject: drm/i915/gvt: fix double free bug in split_2MB_gtt_entry From: Zheng Wang <zyytlz.wz@xxxxxxx> commit 4a61648af68f5ba4884f0e3b494ee1cabc4b6620 upstream. 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: Ovidiu Panait <ovidiu.panait@xxxxxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/gpu/drm/i915/gvt/gtt.c | 17 +++++++++++++---- 1 file changed, 13 insertions(+), 4 deletions(-) --- a/drivers/gpu/drm/i915/gvt/gtt.c +++ b/drivers/gpu/drm/i915/gvt/gtt.c @@ -1155,10 +1155,8 @@ static int split_2MB_gtt_entry(struct in for_each_shadow_entry(sub_spt, &sub_se, sub_index) { ret = intel_gvt_hypervisor_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. */ @@ -1177,6 +1175,17 @@ static int split_2MB_gtt_entry(struct in 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, Patches currently in stable-queue which might be from zyytlz.wz@xxxxxxx are queue-4.19/drm-i915-gvt-fix-double-free-bug-in-split_2mb_gtt_entry.patch