From: "Ghimiray, Himal Prasad" <himal.prasad.ghimiray@intel.com>
To: Dan Carpenter <dan.carpenter@linaro.org>
Cc: <intel-xe@lists.freedesktop.org>
Subject: Re: [bug report] drm/xe: Reset VMA attributes to default in SVM garbage collector
Date: Thu, 28 Aug 2025 16:18:11 +0530 [thread overview]
Message-ID: <8e37eb4d-eaba-4e28-bda3-52b9a76a6936@intel.com> (raw)
In-Reply-To: <aLAwP0xAjMpLLpFm@stanley.mountain>
On 28-08-2025 16:02, Dan Carpenter wrote:
> Hello Himal Prasad Ghimiray,
>
> Commit a2eb8aec3ebe ("drm/xe: Reset VMA attributes to default in SVM
> garbage collector") from Aug 21, 2025 (linux-next), leads to the
> following Smatch static checker warning:
>
> drivers/gpu/drm/xe/xe_vm.c:4442 xe_vm_alloc_vma()
> error: uninitialized symbol 'default_pat'.
>
> drivers/gpu/drm/xe/xe_vm.c
> 4396 static int xe_vm_alloc_vma(struct xe_vm *vm,
> 4397 struct drm_gpuvm_map_req *map_req,
> 4398 bool is_madvise)
> 4399 {
> 4400 struct xe_vma_ops vops;
> 4401 struct drm_gpuva_ops *ops = NULL;
> 4402 struct drm_gpuva_op *__op;
> 4403 bool is_cpu_addr_mirror = false;
> 4404 bool remap_op = false;
> 4405 struct xe_vma_mem_attr tmp_attr;
> 4406 u16 default_pat;
> 4407 int err;
> 4408
> 4409 lockdep_assert_held_write(&vm->lock);
> 4410
> 4411 if (is_madvise)
> 4412 ops = drm_gpuvm_madvise_ops_create(&vm->gpuvm, map_req);
> 4413 else
> 4414 ops = drm_gpuvm_sm_map_ops_create(&vm->gpuvm, map_req);
> 4415
> 4416 if (IS_ERR(ops))
> 4417 return PTR_ERR(ops);
> 4418
> 4419 if (list_empty(&ops->list)) {
> 4420 err = 0;
> 4421 goto free_ops;
> 4422 }
> 4423
> 4424 drm_gpuva_for_each_op(__op, ops) {
> 4425 struct xe_vma_op *op = gpuva_op_to_vma_op(__op);
> 4426 struct xe_vma *vma = NULL;
> 4427
> 4428 if (!is_madvise) {
> 4429 if (__op->op == DRM_GPUVA_OP_UNMAP) {
> 4430 vma = gpuva_to_vma(op->base.unmap.va);
> 4431 XE_WARN_ON(!xe_vma_has_default_mem_attrs(vma));
> 4432 default_pat = vma->attr.default_pat_index;
> 4433 }
> 4434
> 4435 if (__op->op == DRM_GPUVA_OP_REMAP) {
> 4436 vma = gpuva_to_vma(op->base.remap.unmap->va);
> 4437 default_pat = vma->attr.default_pat_index;
> 4438 }
> 4439
> 4440 if (__op->op == DRM_GPUVA_OP_MAP) {
> 4441 op->map.is_cpu_addr_mirror = true;
> --> 4442 op->map.pat_index = default_pat;
>
> Maybe we *know* the __ops are always in a specifc order so
> REMAP and UNMAP come before MAP??
True MAP is always follwed by REMAP.
>
> 4443 }
> 4444 } else {
> 4445 if (__op->op == DRM_GPUVA_OP_REMAP) {
> 4446 vma = gpuva_to_vma(op->base.remap.unmap->va);
> 4447 xe_assert(vm->xe, !remap_op);
> 4448 xe_assert(vm->xe, xe_vma_has_no_bo(vma));
> 4449 remap_op = true;
> 4450
> 4451 if (xe_vma_is_cpu_addr_mirror(vma))
> 4452 is_cpu_addr_mirror = true;
> 4453 else
> 4454 is_cpu_addr_mirror = false;
> 4455 }
> 4456
> 4457 if (__op->op == DRM_GPUVA_OP_MAP) {
> 4458 xe_assert(vm->xe, remap_op);
> 4459 remap_op = false;
> 4460 /*
> 4461 * In case of madvise ops DRM_GPUVA_OP_MAP is
> 4462 * always after DRM_GPUVA_OP_REMAP, so ensure
> 4463 * we assign op->map.is_cpu_addr_mirror true
> 4464 * if REMAP is for xe_vma_is_cpu_addr_mirror vma
> 4465 */
> 4466 op->map.is_cpu_addr_mirror = is_cpu_addr_mirror;
> 4467 }
> 4468 }
> 4469 print_op(vm->xe, __op);
> 4470 }
> 4471
> 4472 xe_vma_ops_init(&vops, vm, NULL, NULL, 0);
> 4473
> 4474 if (is_madvise)
> 4475 vops.flags |= XE_VMA_OPS_FLAG_MADVISE;
> 4476
> 4477 err = vm_bind_ioctl_ops_parse(vm, ops, &vops);
> 4478 if (err)
> 4479 goto unwind_ops;
> 4480
> 4481 xe_vm_lock(vm, false);
> 4482
> 4483 drm_gpuva_for_each_op(__op, ops) {
> 4484 struct xe_vma_op *op = gpuva_op_to_vma_op(__op);
> 4485 struct xe_vma *vma;
> 4486
> 4487 if (__op->op == DRM_GPUVA_OP_UNMAP) {
> 4488 vma = gpuva_to_vma(op->base.unmap.va);
> 4489 /* There should be no unmap for madvise */
> 4490 if (is_madvise)
> 4491 XE_WARN_ON("UNEXPECTED UNMAP");
> 4492
> 4493 xe_vma_destroy(vma, NULL);
> 4494 } else if (__op->op == DRM_GPUVA_OP_REMAP) {
> 4495 vma = gpuva_to_vma(op->base.remap.unmap->va);
> 4496 /* In case of madvise ops Store attributes for REMAP UNMAPPED
> 4497 * VMA, so they can be assigned to newly MAP created vma.
> 4498 */
> 4499 if (is_madvise)
> 4500 tmp_attr = vma->attr;
> 4501
> 4502 xe_vma_destroy(gpuva_to_vma(op->base.remap.unmap->va), NULL);
> 4503 } else if (__op->op == DRM_GPUVA_OP_MAP) {
> 4504 vma = op->map.vma;
> 4505 /* In case of madvise call, MAP will always be follwed by REMAP.
> 4506 * Therefore temp_attr will always have sane values, making it safe to
> 4507 * copy them to new vma.
> 4508 */
> 4509 if (is_madvise)
> 4510 vma->attr = tmp_attr;
> 4511 }
> 4512 }
> 4513
> 4514 xe_vm_unlock(vm);
> 4515 drm_gpuva_ops_free(&vm->gpuvm, ops);
> 4516 return 0;
> 4517
> 4518 unwind_ops:
> 4519 vm_bind_ioctl_ops_unwind(vm, &ops, 1);
> 4520 free_ops:
> 4521 drm_gpuva_ops_free(&vm->gpuvm, ops);
> 4522 return err;
> 4523 }
>
> regards,
> dan carpenter
next prev parent reply other threads:[~2025-08-28 10:48 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-08-28 10:32 [bug report] drm/xe: Reset VMA attributes to default in SVM garbage collector Dan Carpenter
2025-08-28 10:48 ` Ghimiray, Himal Prasad [this message]
2025-08-28 14:28 ` Dan Carpenter
2025-09-01 5:41 ` Ghimiray, Himal Prasad
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