From 70982eef4d7eebb47a3b1ef25ec1bc742f3a21cf Mon Sep 17 00:00:00 2001 From: xinhui pan Date: Tue, 7 Sep 2021 12:08:32 +0800 Subject: [PATCH 1/1] drm/ttm: Fix a deadlock if the target BO is not idle during swap MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit The ret value might be -EBUSY, caller will think lru lock is still locked but actually NOT. So return -ENOSPC instead. Otherwise we hit list corruption. ttm_bo_cleanup_refs might fail too if BO is not idle. If we return 0, caller(ttm_tt_populate -> ttm_global_swapout ->ttm_device_swapout) will be stuck as we actually did not free any BO memory. This usually happens when the fence is not signaled for a long time. Signed-off-by: xinhui pan Reviewed-by: Christian König Fixes: ebd59851c796 ("drm/ttm: move swapout logic around v3") Link: https://patchwork.freedesktop.org/patch/msgid/20210907040832.1107747-1-xinhui.pan@amd.com Signed-off-by: Christian König Signed-off-by: Dave Airlie --- drivers/gpu/drm/ttm/ttm_bo.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c index ea4add2b9717..bb9e02c31946 100644 --- a/drivers/gpu/drm/ttm/ttm_bo.c +++ b/drivers/gpu/drm/ttm/ttm_bo.c @@ -1160,9 +1160,9 @@ int ttm_bo_swapout(struct ttm_buffer_object *bo, struct ttm_operation_ctx *ctx, } if (bo->deleted) { - ttm_bo_cleanup_refs(bo, false, false, locked); + ret = ttm_bo_cleanup_refs(bo, false, false, locked); ttm_bo_put(bo); - return 0; + return ret == -EBUSY ? -ENOSPC : ret; } ttm_bo_del_from_lru(bo); @@ -1216,7 +1216,7 @@ out: if (locked) dma_resv_unlock(bo->base.resv); ttm_bo_put(bo); - return ret; + return ret == -EBUSY ? -ENOSPC : ret; } void ttm_bo_tt_destroy(struct ttm_buffer_object *bo) -- 2.20.1