From: Vasily Averin vvs@virtuozzo.com
commit 933db73351d359f74b14f4af095808260aff11f9 upstream.
qxl_release should not be accesses after qxl_push_*_ring_release() calls: userspace driver can process submitted command quickly, move qxl_release into release_ring, generate interrupt and trigger garbage collector.
It can lead to crashes in qxl driver or trigger memory corruption in some kmalloc-192 slab object
Gerd Hoffmann proposes to swap the qxl_release_fence_buffer_objects() + qxl_push_{cursor,command}_ring_release() calls to close that race window.
cc: stable@vger.kernel.org Fixes: f64122c1f6ad ("drm: add new QXL driver. (v1.4)") Signed-off-by: Vasily Averin vvs@virtuozzo.com Link: http://patchwork.freedesktop.org/patch/msgid/fa17b338-66ae-f299-68fe-8d32419... Signed-off-by: Gerd Hoffmann kraxel@redhat.com [backported to v4.14-stable] Signed-off-by: Vasily Averin vvs@virtuozzo.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/gpu/drm/qxl/qxl_cmd.c | 5 ++--- drivers/gpu/drm/qxl/qxl_display.c | 6 +++--- drivers/gpu/drm/qxl/qxl_draw.c | 8 ++++---- drivers/gpu/drm/qxl/qxl_ioctl.c | 5 +---- 4 files changed, 10 insertions(+), 14 deletions(-)
--- a/drivers/gpu/drm/qxl/qxl_cmd.c +++ b/drivers/gpu/drm/qxl/qxl_cmd.c @@ -533,8 +533,8 @@ int qxl_hw_surface_alloc(struct qxl_devi /* no need to add a release to the fence for this surface bo, since it is only released when we ask to destroy the surface and it would never signal otherwise */ - qxl_push_command_ring_release(qdev, release, QXL_CMD_SURFACE, false); qxl_release_fence_buffer_objects(release); + qxl_push_command_ring_release(qdev, release, QXL_CMD_SURFACE, false);
surf->hw_surf_alloc = true; spin_lock(&qdev->surf_id_idr_lock); @@ -576,9 +576,8 @@ int qxl_hw_surface_dealloc(struct qxl_de cmd->surface_id = id; qxl_release_unmap(qdev, release, &cmd->release_info);
- qxl_push_command_ring_release(qdev, release, QXL_CMD_SURFACE, false); - qxl_release_fence_buffer_objects(release); + qxl_push_command_ring_release(qdev, release, QXL_CMD_SURFACE, false);
return 0; } --- a/drivers/gpu/drm/qxl/qxl_display.c +++ b/drivers/gpu/drm/qxl/qxl_display.c @@ -533,8 +533,8 @@ static int qxl_primary_apply_cursor(stru cmd->u.set.visible = 1; qxl_release_unmap(qdev, release, &cmd->release_info);
- qxl_push_cursor_ring_release(qdev, release, QXL_CMD_CURSOR, false); qxl_release_fence_buffer_objects(release); + qxl_push_cursor_ring_release(qdev, release, QXL_CMD_CURSOR, false);
return ret;
@@ -701,8 +701,8 @@ static void qxl_cursor_atomic_update(str cmd->u.position.y = plane->state->crtc_y + fb->hot_y;
qxl_release_unmap(qdev, release, &cmd->release_info); - qxl_push_cursor_ring_release(qdev, release, QXL_CMD_CURSOR, false); qxl_release_fence_buffer_objects(release); + qxl_push_cursor_ring_release(qdev, release, QXL_CMD_CURSOR, false);
if (old_cursor_bo) qxl_bo_unref(&old_cursor_bo); @@ -747,8 +747,8 @@ static void qxl_cursor_atomic_disable(st cmd->type = QXL_CURSOR_HIDE; qxl_release_unmap(qdev, release, &cmd->release_info);
- qxl_push_cursor_ring_release(qdev, release, QXL_CMD_CURSOR, false); qxl_release_fence_buffer_objects(release); + qxl_push_cursor_ring_release(qdev, release, QXL_CMD_CURSOR, false); }
static int qxl_plane_prepare_fb(struct drm_plane *plane, --- a/drivers/gpu/drm/qxl/qxl_draw.c +++ b/drivers/gpu/drm/qxl/qxl_draw.c @@ -241,8 +241,8 @@ void qxl_draw_opaque_fb(const struct qxl qxl_bo_physical_address(qdev, dimage->bo, 0); qxl_release_unmap(qdev, release, &drawable->release_info);
- qxl_push_command_ring_release(qdev, release, QXL_CMD_DRAW, false); qxl_release_fence_buffer_objects(release); + qxl_push_command_ring_release(qdev, release, QXL_CMD_DRAW, false);
out_free_palette: if (palette_bo) @@ -382,8 +382,8 @@ void qxl_draw_dirty_fb(struct qxl_device } qxl_bo_kunmap(clips_bo);
- qxl_push_command_ring_release(qdev, release, QXL_CMD_DRAW, false); qxl_release_fence_buffer_objects(release); + qxl_push_command_ring_release(qdev, release, QXL_CMD_DRAW, false);
out_release_backoff: if (ret) @@ -433,8 +433,8 @@ void qxl_draw_copyarea(struct qxl_device drawable->u.copy_bits.src_pos.y = sy; qxl_release_unmap(qdev, release, &drawable->release_info);
- qxl_push_command_ring_release(qdev, release, QXL_CMD_DRAW, false); qxl_release_fence_buffer_objects(release); + qxl_push_command_ring_release(qdev, release, QXL_CMD_DRAW, false);
out_free_release: if (ret) @@ -477,8 +477,8 @@ void qxl_draw_fill(struct qxl_draw_fill
qxl_release_unmap(qdev, release, &drawable->release_info);
- qxl_push_command_ring_release(qdev, release, QXL_CMD_DRAW, false); qxl_release_fence_buffer_objects(release); + qxl_push_command_ring_release(qdev, release, QXL_CMD_DRAW, false);
out_free_release: if (ret) --- a/drivers/gpu/drm/qxl/qxl_ioctl.c +++ b/drivers/gpu/drm/qxl/qxl_ioctl.c @@ -257,11 +257,8 @@ static int qxl_process_single_command(st apply_surf_reloc(qdev, &reloc_info[i]); }
+ qxl_release_fence_buffer_objects(release); ret = qxl_push_command_ring_release(qdev, release, cmd->type, true); - if (ret) - qxl_release_backoff_reserve_list(release); - else - qxl_release_fence_buffer_objects(release);
out_free_bos: out_free_release: