6.10-stable review patch. If anyone has any objections, please let me know.
------------------
From: Boris Brezillon boris.brezillon@collabora.com
[ Upstream commit fa998a9eac8809da4f219aad49836fcad2a9bf5c ]
drm_gpuvm_bo_obtain_prealloc() will call drm_gpuvm_bo_put() on our pre-allocated BO if the <BO,VM> 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 boris.brezillon@collabora.com Reviewed-by: Liviu Dudau liviu.dudau@arm.com Reviewed-by: Steven Price steven.price@arm.com Link: https://patchwork.freedesktop.org/patch/msgid/20240913112722.492144-1-boris.... Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/gpu/drm/panthor/panthor_mmu.c | 8 ++++++++ 1 file changed, 8 insertions(+)
diff --git a/drivers/gpu/drm/panthor/panthor_mmu.c b/drivers/gpu/drm/panthor/panthor_mmu.c index cc6e13a977835..ce8e8a93d7076 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 <BO,VM> 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 <VM,BO> combination exists, it already * retains a pin ref, and we can release the one we took earlier.