Hello Jeykumar Sankaran,
The patch 25fdd5933e4c: "drm/msm: Add SDM845 DPU support" from Jun 27, 2018, leads to the following Smatch static checker warning:
drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c:1679 dpu_plane_init() warn: '&pdpu->mplane_list' not removed from list
drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c 1567 struct drm_plane *dpu_plane_init(struct drm_device *dev, 1568 uint32_t pipe, enum drm_plane_type type, 1569 unsigned long possible_crtcs, u32 master_plane_id) 1570 { 1571 struct drm_plane *plane = NULL, *master_plane = NULL; 1572 const uint32_t *format_list; 1573 struct dpu_plane *pdpu; 1574 struct msm_drm_private *priv = dev->dev_private; 1575 struct dpu_kms *kms = to_dpu_kms(priv->kms); 1576 int zpos_max = DPU_ZPOS_MAX; 1577 uint32_t num_formats; 1578 int ret = -EINVAL; 1579 1580 /* create and zero local structure */ 1581 pdpu = kzalloc(sizeof(*pdpu), GFP_KERNEL); 1582 if (!pdpu) { 1583 DPU_ERROR("[%u]failed to allocate local plane struct\n", pipe); 1584 ret = -ENOMEM; 1585 return ERR_PTR(ret); 1586 } 1587 1588 /* cache local stuff for later */ 1589 plane = &pdpu->base; 1590 pdpu->pipe = pipe; 1591 pdpu->is_virtual = (master_plane_id != 0); 1592 INIT_LIST_HEAD(&pdpu->mplane_list); 1593 master_plane = drm_plane_find(dev, NULL, master_plane_id); 1594 if (master_plane) { 1595 struct dpu_plane *mpdpu = to_dpu_plane(master_plane); 1596 1597 list_add_tail(&pdpu->mplane_list, &mpdpu->mplane_list); ^^^^^^^^^^^^^^^^^ This is not removed from the list in the error handling code so it will lead to a Use After Free.
1598 } 1599 1600 /* initialize underlying h/w driver */ 1601 pdpu->pipe_hw = dpu_hw_sspp_init(pipe, kms->mmio, kms->catalog, 1602 master_plane_id != 0); 1603 if (IS_ERR(pdpu->pipe_hw)) { 1604 DPU_ERROR("[%u]SSPP init failed\n", pipe); 1605 ret = PTR_ERR(pdpu->pipe_hw); 1606 goto clean_plane; 1607 } else if (!pdpu->pipe_hw->cap || !pdpu->pipe_hw->cap->sblk) { 1608 DPU_ERROR("[%u]SSPP init returned invalid cfg\n", pipe); 1609 goto clean_sspp; 1610 } 1611 1612 /* cache features mask for later */ 1613 pdpu->features = pdpu->pipe_hw->cap->features; 1614 pdpu->pipe_sblk = pdpu->pipe_hw->cap->sblk; 1615 if (!pdpu->pipe_sblk) { 1616 DPU_ERROR("[%u]invalid sblk\n", pipe); 1617 goto clean_sspp; 1618 } 1619 1620 if (pdpu->is_virtual) { 1621 format_list = pdpu->pipe_sblk->virt_format_list; 1622 num_formats = pdpu->pipe_sblk->virt_num_formats; 1623 } 1624 else { 1625 format_list = pdpu->pipe_sblk->format_list; 1626 num_formats = pdpu->pipe_sblk->num_formats; 1627 } 1628 1629 ret = drm_universal_plane_init(dev, plane, 0xff, &dpu_plane_funcs, 1630 format_list, num_formats, 1631 supported_format_modifiers, type, NULL); 1632 if (ret) 1633 goto clean_sspp; 1634 1635 pdpu->catalog = kms->catalog; 1636 1637 if (kms->catalog->mixer_count && 1638 kms->catalog->mixer[0].sblk->maxblendstages) { 1639 zpos_max = kms->catalog->mixer[0].sblk->maxblendstages - 1; 1640 if (zpos_max > DPU_STAGE_MAX - DPU_STAGE_0 - 1) 1641 zpos_max = DPU_STAGE_MAX - DPU_STAGE_0 - 1; 1642 } 1643 1644 ret = drm_plane_create_zpos_property(plane, 0, 0, zpos_max); 1645 if (ret) 1646 DPU_ERROR("failed to install zpos property, rc = %d\n", ret); 1647 1648 drm_plane_create_alpha_property(plane); 1649 drm_plane_create_blend_mode_property(plane, 1650 BIT(DRM_MODE_BLEND_PIXEL_NONE) | 1651 BIT(DRM_MODE_BLEND_PREMULTI) | 1652 BIT(DRM_MODE_BLEND_COVERAGE)); 1653 1654 drm_plane_create_rotation_property(plane, 1655 DRM_MODE_ROTATE_0, 1656 DRM_MODE_ROTATE_0 | 1657 DRM_MODE_ROTATE_180 | 1658 DRM_MODE_REFLECT_X | 1659 DRM_MODE_REFLECT_Y); 1660 1661 drm_plane_enable_fb_damage_clips(plane); 1662 1663 /* success! finalize initialization */ 1664 drm_plane_helper_add(plane, &dpu_plane_helper_funcs); 1665 1666 /* save user friendly pipe name for later */ 1667 snprintf(pdpu->pipe_name, DPU_NAME_SIZE, "plane%u", plane->base.id); 1668 1669 mutex_init(&pdpu->lock); 1670 1671 DPU_DEBUG("%s created for pipe:%u id:%u virtual:%u\n", pdpu->pipe_name, 1672 pipe, plane->base.id, master_plane_id); 1673 return plane; 1674 1675 clean_sspp: 1676 if (pdpu && pdpu->pipe_hw) 1677 dpu_hw_sspp_destroy(pdpu->pipe_hw); 1678 clean_plane: --> 1679 kfree(pdpu); 1680 return ERR_PTR(ret); 1681 }
regards, dan carpenter