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Both are async call in different tasks. Sync svm_bo > unref operation to avoid random "use-after-free". > > Signed-off-by: Xiaogang.Chen > --- > drivers/gpu/drm/amd/amdkfd/kfd_svm.c | 9 +++++++++ > 1 file changed, 9 insertions(+) > > diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c > index 70aa882636ab..8e246e848018 100644 > --- a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c > +++ b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c > @@ -637,6 +637,15 @@ void svm_range_vram_node_free(struct svm_range *prange) > { > svm_range_bo_unref(prange->svm_bo); > prange->ttm_res = NULL; Are above two lines not removed? Regards, Eric > + /* serialize prange->svm_bo unref */ > + mutex_lock(&prange->lock); > + /* prange->svm_bo has not been unref */ > + if (prange->ttm_res) { > + prange->ttm_res = NULL; > + mutex_unlock(&prange->lock); > + svm_range_bo_unref(prange->svm_bo); > + } else > + mutex_unlock(&prange->lock); > } > > struct kfd_node *