This is a note to let you know that I've just added the patch titled drm/vmwgfx: Make sure backup_handle is always valid to the 4.4-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-vmwgfx-make-sure-backup_handle-is-always-valid.patch and it can be found in the queue-4.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 07678eca2cf9c9a18584e546c2b2a0d0c9a3150c Mon Sep 17 00:00:00 2001 From: Sinclair Yeh <syeh@xxxxxxxxxx> Date: Fri, 2 Jun 2017 07:50:57 +0200 Subject: drm/vmwgfx: Make sure backup_handle is always valid From: Sinclair Yeh <syeh@xxxxxxxxxx> commit 07678eca2cf9c9a18584e546c2b2a0d0c9a3150c upstream. When vmw_gb_surface_define_ioctl() is called with an existing buffer, we end up returning an uninitialized variable in the backup_handle. The fix is to first initialize backup_handle to 0 just to be sure, and second, when a user-provided buffer is found, we will use the req->buffer_handle as the backup_handle. Reported-by: Murray McAllister <murray.mcallister@xxxxxxxxxxxxxxx> Signed-off-by: Sinclair Yeh <syeh@xxxxxxxxxx> Reviewed-by: Deepak Rawat <drawat@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/gpu/drm/vmwgfx/vmwgfx_surface.c | 18 +++++++++++------- 1 file changed, 11 insertions(+), 7 deletions(-) --- a/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c @@ -1288,7 +1288,7 @@ int vmw_gb_surface_define_ioctl(struct d struct ttm_object_file *tfile = vmw_fpriv(file_priv)->tfile; int ret; uint32_t size; - uint32_t backup_handle; + uint32_t backup_handle = 0; if (req->multisample_count != 0) return -EINVAL; @@ -1331,12 +1331,16 @@ int vmw_gb_surface_define_ioctl(struct d ret = vmw_user_dmabuf_lookup(tfile, req->buffer_handle, &res->backup, &user_srf->backup_base); - if (ret == 0 && res->backup->base.num_pages * PAGE_SIZE < - res->backup_size) { - DRM_ERROR("Surface backup buffer is too small.\n"); - vmw_dmabuf_unreference(&res->backup); - ret = -EINVAL; - goto out_unlock; + if (ret == 0) { + if (res->backup->base.num_pages * PAGE_SIZE < + res->backup_size) { + DRM_ERROR("Surface backup buffer is too small.\n"); + vmw_dmabuf_unreference(&res->backup); + ret = -EINVAL; + goto out_unlock; + } else { + backup_handle = req->buffer_handle; + } } } else if (req->drm_surface_flags & drm_vmw_surface_flag_create_buffer) ret = vmw_user_dmabuf_alloc(dev_priv, tfile, Patches currently in stable-queue which might be from syeh@xxxxxxxxxx are queue-4.4/drm-vmwgfx-limit-the-number-of-mip-levels-in-vmw_gb_surface_define_ioctl.patch queue-4.4/drm-vmwgfx-make-sure-backup_handle-is-always-valid.patch queue-4.4/drm-vmwgfx-handle-vmalloc-failure-in-vmw_local_fifo_reserve.patch