Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 5.14 051/100] drm/ttm: Fix a deadlock if the target BO is not idle during swap | Date | Fri, 24 Sep 2021 14:44:00 +0200 |
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From: xinhui pan <xinhui.pan@amd.com>
[ Upstream commit 70982eef4d7eebb47a3b1ef25ec1bc742f3a21cf ]
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 <xinhui.pan@amd.com> Reviewed-by: Christian König <christian.koenig@amd.com> 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 <christian.koenig@amd.com> Signed-off-by: Dave Airlie <airlied@redhat.com> Signed-off-by: Sasha Levin <sashal@kernel.org> --- 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 32202385073a..b47a5053eb85 100644 --- a/drivers/gpu/drm/ttm/ttm_bo.c +++ b/drivers/gpu/drm/ttm/ttm_bo.c @@ -1157,9 +1157,9 @@ 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); @@ -1213,7 +1213,7 @@ 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) -- 2.33.0
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