6.1-stable review patch. If anyone has any objections, please let me know.
------------------
From: Zack Rusin zackr@vmware.com
commit f9e96bf1905479f18e83a3a4c314a8dfa56ede2c upstream.
vmw_bo_unreference sets the input buffer to null on exit, resulting in null ptr deref's on the subsequent drm gem put calls.
This went unnoticed because only very old userspace would be exercising those paths but it wouldn't be hard to hit on old distros with brand new kernels.
Introduce a new function that abstracts unrefing of user bo's to make the code cleaner and more explicit.
Signed-off-by: Zack Rusin zackr@vmware.com Reported-by: Ian Forbes iforbes@vmware.com Fixes: 9ef8d83e8e25 ("drm/vmwgfx: Do not drop the reference to the handle too soon") Cc: stable@vger.kernel.org # v6.4+ Reviewed-by: Maaz Mombasawalamombasawalam@vmware.com Link: https://patchwork.freedesktop.org/patch/msgid/20230818041301.407636-1-zack@k... Signed-off-by: Jocelyn Falempe jfalempe@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/gpu/drm/vmwgfx/vmwgfx_bo.c | 6 ++---- drivers/gpu/drm/vmwgfx/vmwgfx_drv.h | 8 ++++++++ drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c | 6 ++---- drivers/gpu/drm/vmwgfx/vmwgfx_kms.c | 6 ++---- drivers/gpu/drm/vmwgfx/vmwgfx_overlay.c | 3 +-- drivers/gpu/drm/vmwgfx/vmwgfx_shader.c | 3 +-- 6 files changed, 16 insertions(+), 16 deletions(-)
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_bo.c +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_bo.c @@ -595,10 +595,9 @@ static int vmw_user_bo_synccpu_release(s if (!(flags & drm_vmw_synccpu_allow_cs)) { atomic_dec(&vmw_bo->cpu_writers); } - ttm_bo_put(&vmw_bo->base); + vmw_user_bo_unref(vmw_bo); }
- drm_gem_object_put(&vmw_bo->base.base); return ret; }
@@ -638,8 +637,7 @@ int vmw_user_bo_synccpu_ioctl(struct drm return ret;
ret = vmw_user_bo_synccpu_grab(vbo, arg->flags); - vmw_bo_unreference(&vbo); - drm_gem_object_put(&vbo->base.base); + vmw_user_bo_unref(vbo); if (unlikely(ret != 0)) { if (ret == -ERESTARTSYS || ret == -EBUSY) return -EBUSY; --- a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.h +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.h @@ -1600,6 +1600,14 @@ vmw_bo_reference(struct vmw_buffer_objec return buf; }
+static inline void vmw_user_bo_unref(struct vmw_buffer_object *vbo) +{ + if (vbo) { + ttm_bo_put(&vbo->base); + drm_gem_object_put(&vbo->base.base); + } +} + static inline void vmw_fifo_resource_inc(struct vmw_private *dev_priv) { atomic_inc(&dev_priv->num_fifo_resources); --- a/drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c @@ -1159,8 +1159,7 @@ static int vmw_translate_mob_ptr(struct return PTR_ERR(vmw_bo); } ret = vmw_validation_add_bo(sw_context->ctx, vmw_bo, true, false); - ttm_bo_put(&vmw_bo->base); - drm_gem_object_put(&vmw_bo->base.base); + vmw_user_bo_unref(vmw_bo); if (unlikely(ret != 0)) return ret;
@@ -1214,8 +1213,7 @@ static int vmw_translate_guest_ptr(struc return PTR_ERR(vmw_bo); } ret = vmw_validation_add_bo(sw_context->ctx, vmw_bo, false, false); - ttm_bo_put(&vmw_bo->base); - drm_gem_object_put(&vmw_bo->base.base); + vmw_user_bo_unref(vmw_bo); if (unlikely(ret != 0)) return ret;
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c @@ -1599,10 +1599,8 @@ static struct drm_framebuffer *vmw_kms_f
err_out: /* vmw_user_lookup_handle takes one ref so does new_fb */ - if (bo) { - vmw_bo_unreference(&bo); - drm_gem_object_put(&bo->base.base); - } + if (bo) + vmw_user_bo_unref(bo); if (surface) vmw_surface_unreference(&surface);
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_overlay.c +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_overlay.c @@ -457,8 +457,7 @@ int vmw_overlay_ioctl(struct drm_device
ret = vmw_overlay_update_stream(dev_priv, buf, arg, true);
- vmw_bo_unreference(&buf); - drm_gem_object_put(&buf->base.base); + vmw_user_bo_unref(buf);
out_unlock: mutex_unlock(&overlay->mutex); --- a/drivers/gpu/drm/vmwgfx/vmwgfx_shader.c +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_shader.c @@ -806,8 +806,7 @@ static int vmw_shader_define(struct drm_ shader_type, num_input_sig, num_output_sig, tfile, shader_handle); out_bad_arg: - vmw_bo_unreference(&buffer); - drm_gem_object_put(&buffer->base.base); + vmw_user_bo_unref(buffer); return ret; }