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drm/gem-vram: Fix deadlock in drm_gem_vram_vmap() 

Recently DRM framebuffer core and all drivers were moved to unlocked
vmapping functions that take the reservation lock. The drm_gem_vram_vmap()
was missed out by accident and now deadlocks drivers that use drm_gem_vram
helpers when framebuffer is updated, like Bochs driver. Remove the locking
from drm_gem_vram_v[un]map() functions to fix the deadlock.

Reported-by: Dmitry Vyukov <dvyukov@google.com>
Fixes: 79e2cf2e7a ("drm/gem: Take reservation lock for vmap/vunmap operations")
Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221113233850.427704-1-dmitry.osipenko@collabora.com
This commit is contained in:
Dmitry Osipenko 2022-11-14 02:38:50 +03:00
parent b1d39f0f42
commit 6d0bfef7da
1 changed files with 3 additions and 15 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

18
drivers/gpu/drm/drm_gem_vram_helper.c
View File

@ -433,25 +433,19 @@ int drm_gem_vram_vmap(struct drm_gem_vram_object *gbo, struct iosys_map *map)
{
int ret;
ret = ttm_bo_reserve(&gbo->bo, true, false, NULL);
if (ret)
return ret;
dma_resv_assert_held(gbo->bo.base.resv);
ret = drm_gem_vram_pin_locked(gbo, 0);
if (ret)
goto err_ttm_bo_unreserve;
return ret;
ret = drm_gem_vram_kmap_locked(gbo, map);
if (ret)
goto err_drm_gem_vram_unpin_locked;
ttm_bo_unreserve(&gbo->bo);
return 0;
err_drm_gem_vram_unpin_locked:
drm_gem_vram_unpin_locked(gbo);
err_ttm_bo_unreserve:
ttm_bo_unreserve(&gbo->bo);
return ret;
}
EXPORT_SYMBOL(drm_gem_vram_vmap);
@ -467,16 +461,10 @@ EXPORT_SYMBOL(drm_gem_vram_vmap);
void drm_gem_vram_vunmap(struct drm_gem_vram_object *gbo,
struct iosys_map *map)
{
int ret;
ret = ttm_bo_reserve(&gbo->bo, false, false, NULL);
if (WARN_ONCE(ret, "ttm_bo_reserve_failed(): ret=%d\n", ret))
return;
dma_resv_assert_held(gbo->bo.base.resv);
drm_gem_vram_kunmap_locked(gbo, map);
drm_gem_vram_unpin_locked(gbo);
ttm_bo_unreserve(&gbo->bo);
}
EXPORT_SYMBOL(drm_gem_vram_vunmap);