From: Christian König Date: Fri, 15 Jul 2022 07:57:22 +0000 (+0200) Subject: drm/ttm: fix locking in vmap/vunmap TTM GEM helpers X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=dbd0da2453c694f2f74651834d90fb280b57f151;p=linux.git drm/ttm: fix locking in vmap/vunmap TTM GEM helpers I've stumbled over this while reviewing patches for DMA-buf and it looks like we completely messed the locking up here. In general most TTM function should only be called while holding the appropriate BO resv lock. Without this we could break the internal buffer object state here. Only compile tested! Signed-off-by: Christian König Fixes: 43676605f890 ("drm/ttm: Add vmap/vunmap to TTM and TTM GEM helpers") Cc: stable@vger.kernel.org Reviewed-by: Dmitry Osipenko Link: https://patchwork.freedesktop.org/patch/msgid/20220715111533.467012-1-christian.koenig@amd.com --- diff --git a/drivers/gpu/drm/drm_gem_ttm_helper.c b/drivers/gpu/drm/drm_gem_ttm_helper.c index d5962a34c01d5..e5fc875990c4f 100644 --- a/drivers/gpu/drm/drm_gem_ttm_helper.c +++ b/drivers/gpu/drm/drm_gem_ttm_helper.c @@ -64,8 +64,13 @@ int drm_gem_ttm_vmap(struct drm_gem_object *gem, struct iosys_map *map) { struct ttm_buffer_object *bo = drm_gem_ttm_of_gem(gem); + int ret; + + dma_resv_lock(gem->resv, NULL); + ret = ttm_bo_vmap(bo, map); + dma_resv_unlock(gem->resv); - return ttm_bo_vmap(bo, map); + return ret; } EXPORT_SYMBOL(drm_gem_ttm_vmap); @@ -82,7 +87,9 @@ void drm_gem_ttm_vunmap(struct drm_gem_object *gem, { struct ttm_buffer_object *bo = drm_gem_ttm_of_gem(gem); + dma_resv_lock(gem->resv, NULL); ttm_bo_vunmap(bo, map); + dma_resv_unlock(gem->resv); } EXPORT_SYMBOL(drm_gem_ttm_vunmap);