| Message ID | 1592051425-94019-1-git-send-email-xiyuyang19@fudan.edu.cn (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | drm/ttm: Fix dma_fence refcnt leak when adding move fence | expand |
Am 13.06.20 um 14:30 schrieb Xiyu Yang: > ttm_bo_add_move_fence() invokes dma_fence_get(), which returns a > reference of the specified dma_fence object to "fence" with increased > refcnt. > > When ttm_bo_add_move_fence() returns, local variable "fence" becomes > invalid, so the refcount should be decreased to keep refcount balanced. > > The reference counting issue happens in one exception handling path of > ttm_bo_add_move_fence(). When no_wait_gpu flag is equals to true, the > function forgets to decrease the refcnt increased by dma_fence_get(), > causing a refcnt leak. > > Fix this issue by calling dma_fence_put() when no_wait_gpu flag is > equals to true. > > Signed-off-by: Xiyu Yang <xiyuyang19@fudan.edu.cn> > Signed-off-by: Xin Tan <tanxin.ctf@gmail.com> Reviewed and pushed this one as well as the other ttm fix to drm-misc-fixes. That should show up in Linus tree rather soon. Thanks for the help, Christian. PS: Are you working on some new automated scripts to catch that stuff or how did you stumbled over it? > --- > drivers/gpu/drm/ttm/ttm_bo.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c > index f73b81c2576e..0f20e14a4cfd 100644 > --- a/drivers/gpu/drm/ttm/ttm_bo.c > +++ b/drivers/gpu/drm/ttm/ttm_bo.c > @@ -883,8 +883,10 @@ static int ttm_bo_add_move_fence(struct ttm_buffer_object *bo, > if (!fence) > return 0; > > - if (no_wait_gpu) > + if (no_wait_gpu) { > + dma_fence_put(fence); > return -EBUSY; > + } > > dma_resv_add_shared_fence(bo->base.resv, fence); >
diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c index f73b81c2576e..0f20e14a4cfd 100644 --- a/drivers/gpu/drm/ttm/ttm_bo.c +++ b/drivers/gpu/drm/ttm/ttm_bo.c @@ -883,8 +883,10 @@ static int ttm_bo_add_move_fence(struct ttm_buffer_object *bo, if (!fence) return 0; - if (no_wait_gpu) + if (no_wait_gpu) { + dma_fence_put(fence); return -EBUSY; + } dma_resv_add_shared_fence(bo->base.resv, fence);