From fa998a9eac8809da4f219aad49836fcad2a9bf5c Mon Sep 17 00:00:00 2001 From: Boris Brezillon Date: Fri, 13 Sep 2024 13:27:22 +0200 Subject: drm/panthor: Lock the VM resv before calling drm_gpuvm_bo_obtain_prealloc() drm_gpuvm_bo_obtain_prealloc() will call drm_gpuvm_bo_put() on our pre-allocated BO if the association exists. Given we only have one ref on preallocated_vm_bo, drm_gpuvm_bo_destroy() will be called immediately, and we have to hold the VM resv lock when calling this function. Fixes: 647810ec2476 ("drm/panthor: Add the MMU/VM logical block") Signed-off-by: Boris Brezillon Reviewed-by: Liviu Dudau Reviewed-by: Steven Price Link: https://patchwork.freedesktop.org/patch/msgid/20240913112722.492144-1-boris.brezillon@collabora.com --- drivers/gpu/drm/panthor/panthor_mmu.c | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'drivers') diff --git a/drivers/gpu/drm/panthor/panthor_mmu.c b/drivers/gpu/drm/panthor/panthor_mmu.c index bbc12728437f..3cd2bce59edc 100644 --- a/drivers/gpu/drm/panthor/panthor_mmu.c +++ b/drivers/gpu/drm/panthor/panthor_mmu.c @@ -1251,9 +1251,17 @@ static int panthor_vm_prepare_map_op_ctx(struct panthor_vm_op_ctx *op_ctx, goto err_cleanup; } + /* drm_gpuvm_bo_obtain_prealloc() will call drm_gpuvm_bo_put() on our + * pre-allocated BO if the association exists. Given we + * only have one ref on preallocated_vm_bo, drm_gpuvm_bo_destroy() will + * be called immediately, and we have to hold the VM resv lock when + * calling this function. + */ + dma_resv_lock(panthor_vm_resv(vm), NULL); mutex_lock(&bo->gpuva_list_lock); op_ctx->map.vm_bo = drm_gpuvm_bo_obtain_prealloc(preallocated_vm_bo); mutex_unlock(&bo->gpuva_list_lock); + dma_resv_unlock(panthor_vm_resv(vm)); /* If the a vm_bo for this combination exists, it already * retains a pin ref, and we can release the one we took earlier. -- cgit v1.2.3