On 1/5/2023 10:56 AM, Matthew Auld wrote:
On Fri, 23 Dec 2022 at 09:20, Nirmoy Das <nirmoy.das@xxxxxxxxx> wrote:A nested dma_resv_reserve_fences(1) will not reserve slot from the 2nd call onwards and folowing dma_resv_add_fence() might hit the "BUG_ON(fobj->num_fences >= fobj->max_fences)" check. I915 hit above nested dma_resv case in ttm_bo_handle_move_mem() with async unbind: dma_resv_reserve_fences() from --> ttm_bo_handle_move_mem() dma_resv_reserve_fences() from --> i915_vma_unbind_async() dma_resv_add_fence() from --> i915_vma_unbind_async() dma_resv_add_fence() from -->ttm_bo_move_accel_cleanup() Resolve this by adding an extra fence in i915_vma_unbind_async(). Suggested-by: Thomas Hellström <thomas.hellstrom@xxxxxxxxxxxxxxx> Signed-off-by: Nirmoy Das <nirmoy.das@xxxxxxxxx>Reviewed-by: Matthew Auld <matthew.auld@xxxxxxxxx> Does this need a fixes tag? Fixes: 2f6b90da9192 ("drm/i915: Use vma resources for async unbinding") Cc: <stable@xxxxxxxxxxxxxxx> # v5.18+ I can add when pushing.
Yes, please add that. Thanks, Nirmoy
--- drivers/gpu/drm/i915/i915_vma.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/gpu/drm/i915/i915_vma.c b/drivers/gpu/drm/i915/i915_vma.c index 7d044888ac33..5ac4c1c2403c 100644 --- a/drivers/gpu/drm/i915/i915_vma.c +++ b/drivers/gpu/drm/i915/i915_vma.c @@ -2149,7 +2149,7 @@ int i915_vma_unbind_async(struct i915_vma *vma, bool trylock_vm) if (!obj->mm.rsgt) return -EBUSY; - err = dma_resv_reserve_fences(obj->base.resv, 1); + err = dma_resv_reserve_fences(obj->base.resv, 2); if (err) return -EBUSY; -- 2.38.0
