6.5-stable review patch. If anyone has any objections, please let me know. ------------------ From: Xiaogang Chen <xiaogang.chen@xxxxxxx> [ Upstream commit 7bfaa160caed8192f8262c4638f552cad94bcf5a ] This patch fixes: 1: ref number of prange's svm_bo got decreased by an async call from hmm. When wait svm_bo of prange got released we shoul also wait prang->svm_bo become NULL, otherwise prange->svm_bo may be set to null after allocate new vram buffer. 2: During waiting svm_bo of prange got released in a while loop should reschedule current task to give other tasks oppotunity to run, specially the the workque task that handles svm_bo ref release, otherwise we may enter to softlock. Signed-off-by: Xiaogang.Chen <xiaogang.chen@xxxxxxx> Reviewed-by: Felix Kuehling <Felix.Kuehling@xxxxxxx> Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- drivers/gpu/drm/amd/amdkfd/kfd_svm.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c index 5ff1a5a89d968..a9b57c66cb7d7 100644 --- a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c +++ b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c @@ -484,11 +484,11 @@ svm_range_validate_svm_bo(struct kfd_node *node, struct svm_range *prange) /* We need a new svm_bo. Spin-loop to wait for concurrent * svm_range_bo_release to finish removing this range from - * its range list. After this, it is safe to reuse the - * svm_bo pointer and svm_bo_list head. + * its range list and set prange->svm_bo to null. After this, + * it is safe to reuse the svm_bo pointer and svm_bo_list head. */ - while (!list_empty_careful(&prange->svm_bo_list)) - ; + while (!list_empty_careful(&prange->svm_bo_list) || prange->svm_bo) + cond_resched(); return false; } -- 2.42.0
