Commit 2d2ddb58 authored May 28, 2021 by Christian König

drm/ttm: fix deref of bo->ttm without holding the lock v2



We need to grab the resv lock first before doing that check.

v2 (chk): simplify the change for -fixes

Signed-off-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: Huang Rui <ray.huang@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210528130041.1683-1-christian.koenig@amd.com

parent 9bf37977

drivers/gpu/drm/ttm/ttm_bo.c

+4 −1

Original line number	Diff line number	Diff line
		@@ -1172,7 +1172,10 @@ int ttm_bo_swapout(struct ttm_buffer_object bo, struct ttm_operation_ctx ctx,
		if (!ttm_bo_evict_swapout_allowable(bo, ctx, &locked, NULL))
		return -EBUSY;

		if (!ttm_bo_get_unless_zero(bo)) {
		if (!bo->ttm \|\| !ttm_tt_is_populated(bo->ttm) \|\|
		bo->ttm->page_flags & TTM_PAGE_FLAG_SG \|\|
		bo->ttm->page_flags & TTM_PAGE_FLAG_SWAPPED \|\|
		!ttm_bo_get_unless_zero(bo)) {
		if (locked)
		dma_resv_unlock(bo->base.resv);
		return -EBUSY;

drivers/gpu/drm/ttm/ttm_device.c

+1 −7

Original line number	Diff line number	Diff line
		@@ -143,14 +143,8 @@ int ttm_device_swapout(struct ttm_device bdev, struct ttm_operation_ctx ctx,

		for (j = 0; j < TTM_MAX_BO_PRIORITY; ++j) {
		list_for_each_entry(bo, &man->lru[j], lru) {
		uint32_t num_pages;
		uint32_t num_pages = PFN_UP(bo->base.size);

		if (!bo->ttm \|\| !ttm_tt_is_populated(bo->ttm) \|\|
		bo->ttm->page_flags & TTM_PAGE_FLAG_SG \|\|
		bo->ttm->page_flags & TTM_PAGE_FLAG_SWAPPED)
		continue;

		num_pages = bo->ttm->num_pages;
		ret = ttm_bo_swapout(bo, ctx, gfp_flags);
		/* ttm_bo_swapout has dropped the lru_lock */
		if (!ret)