[Intel-xe] [PATCH 4/5] drm/xe: Prevent evicting for page tables
Thomas Hellström
thomas.hellstrom at linux.intel.com
Fri May 26 12:35:12 UTC 2023
On 5/26/23 14:11, Maarten Lankhorst wrote:
> When creating page tables from xe_exec_ioctl, we may end up freeing
> memory we just validated. To be certain this does not happen, do not
> allow the current reservation to be evicted from the ioctl.
>
> Callchain:
> [ 109.008522] xe_bo_move_notify+0x5c/0xf0 [xe]
> [ 109.008548] xe_bo_move+0x90/0x510 [xe]
> [ 109.008573] ttm_bo_handle_move_mem+0xb7/0x170 [ttm]
> [ 109.008581] ttm_bo_swapout+0x15e/0x360 [ttm]
> [ 109.008586] ttm_device_swapout+0xc2/0x110 [ttm]
> [ 109.008592] ttm_global_swapout+0x47/0xc0 [ttm]
> [ 109.008598] ttm_tt_populate+0x7a/0x130 [ttm]
> [ 109.008603] ttm_bo_handle_move_mem+0x160/0x170 [ttm]
> [ 109.008609] ttm_bo_validate+0xe5/0x1d0 [ttm]
> [ 109.008614] ttm_bo_init_reserved+0xac/0x190 [ttm]
> [ 109.008620] __xe_bo_create_locked+0x153/0x260 [xe]
> [ 109.008645] xe_bo_create_locked_range+0x77/0x360 [xe]
> [ 109.008671] xe_bo_create_pin_map_at+0x33/0x1f0 [xe]
> [ 109.008695] xe_bo_create_pin_map+0x11/0x20 [xe]
> [ 109.008721] xe_pt_create+0x69/0xf0 [xe]
> [ 109.008749] xe_pt_stage_bind_entry+0x208/0x430 [xe]
> [ 109.008776] xe_pt_walk_range+0xe9/0x2a0 [xe]
> [ 109.008802] xe_pt_walk_range+0x223/0x2a0 [xe]
> [ 109.008828] xe_pt_walk_range+0x223/0x2a0 [xe]
> [ 109.008853] __xe_pt_bind_vma+0x28d/0xbd0 [xe]
> [ 109.008878] xe_vm_bind_vma+0xc7/0x2f0 [xe]
> [ 109.008904] xe_vm_rebind+0x72/0x160 [xe]
> [ 109.008930] xe_exec_ioctl+0x22b/0xa70 [xe]
> [ 109.008955] drm_ioctl_kernel+0xb9/0x150 [drm]
> [ 109.008972] drm_ioctl+0x210/0x430 [drm]
> [ 109.008988] __x64_sys_ioctl+0x85/0xb0
> [ 109.008990] do_syscall_64+0x38/0x90
> [ 109.008991] entry_SYSCALL_64_after_hwframe+0x72/0xdc
>
> Original warning:
> [ 5613.149126] WARNING: CPU: 3 PID: 45883 at drivers/gpu/drm/xe/xe_vm.c:504 xe_vm_unlock_dma_resv+0x43/0x50 [xe]
> ...
> [ 5613.226398] RIP: 0010:xe_vm_unlock_dma_resv+0x43/0x50 [xe]
> [ 5613.316098] Call Trace:
> [ 5613.318595] <TASK>
> [ 5613.320743] xe_exec_ioctl+0x383/0x8a0 [xe]
> [ 5613.325278] ? __is_insn_slot_addr+0x8e/0x110
> [ 5613.329719] ? __is_insn_slot_addr+0x8e/0x110
> [ 5613.334116] ? kernel_text_address+0x75/0xf0
> [ 5613.338429] ? __pfx_stack_trace_consume_entry+0x10/0x10
> [ 5613.343778] ? __kernel_text_address+0x9/0x40
> [ 5613.348181] ? unwind_get_return_address+0x1a/0x30
> [ 5613.353013] ? __pfx_stack_trace_consume_entry+0x10/0x10
> [ 5613.358362] ? arch_stack_walk+0x99/0xf0
> [ 5613.362329] ? rcu_read_lock_sched_held+0xb/0x70
> [ 5613.366996] ? lock_acquire+0x287/0x2f0
> [ 5613.370873] ? rcu_read_lock_sched_held+0xb/0x70
> [ 5613.375530] ? rcu_read_lock_sched_held+0xb/0x70
> [ 5613.380181] ? lock_release+0x225/0x2e0
> [ 5613.384059] ? __pfx_xe_exec_ioctl+0x10/0x10 [xe]
> [ 5613.389092] drm_ioctl_kernel+0xc0/0x170
> [ 5613.393068] drm_ioctl+0x1b7/0x490
> [ 5613.396519] ? __pfx_xe_exec_ioctl+0x10/0x10 [xe]
> [ 5613.401547] ? lock_release+0x225/0x2e0
> [ 5613.405432] __x64_sys_ioctl+0x8a/0xb0
> [ 5613.409232] do_syscall_64+0x37/0x90
>
> Signed-off-by: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
> Closes: https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/239
Did you look at passing around the ttm_operation_ctx, or a
"allow_res_evict" bool?
In any case would be good to have this fixed asap, so
Reviewed-by: Thomas Hellström <thomas.hellstrom at linux.intel.com>
> ---
> drivers/gpu/drm/xe/xe_bo.c | 2 +-
> drivers/gpu/drm/xe/xe_bo.h | 7 ++++---
> drivers/gpu/drm/xe/xe_pt.c | 3 ++-
> 3 files changed, 7 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/gpu/drm/xe/xe_bo.c b/drivers/gpu/drm/xe/xe_bo.c
> index 0db9c05097d0..8735facb1cf9 100644
> --- a/drivers/gpu/drm/xe/xe_bo.c
> +++ b/drivers/gpu/drm/xe/xe_bo.c
> @@ -1130,7 +1130,7 @@ struct xe_bo *__xe_bo_create_locked(struct xe_device *xe, struct xe_bo *bo,
> drm_gem_private_object_init(&xe->drm, &bo->ttm.base, size);
>
> if (resv) {
> - ctx.allow_res_evict = true;
> + ctx.allow_res_evict = !(flags & XE_BO_CREATE_NO_RESV_EVICT);
> ctx.resv = resv;
> }
>
> diff --git a/drivers/gpu/drm/xe/xe_bo.h b/drivers/gpu/drm/xe/xe_bo.h
> index a1c51cc0ac3c..dd27d8c7f3b0 100644
> --- a/drivers/gpu/drm/xe/xe_bo.h
> +++ b/drivers/gpu/drm/xe/xe_bo.h
> @@ -27,9 +27,10 @@
> #define XE_BO_CREATE_GGTT_BIT BIT(5)
> #define XE_BO_CREATE_IGNORE_MIN_PAGE_SIZE_BIT BIT(6)
> #define XE_BO_CREATE_PINNED_BIT BIT(7)
> -#define XE_BO_DEFER_BACKING BIT(8)
> -#define XE_BO_SCANOUT_BIT BIT(9)
> -#define XE_BO_FIXED_PLACEMENT_BIT BIT(10)
> +#define XE_BO_CREATE_NO_RESV_EVICT BIT(8)
> +#define XE_BO_DEFER_BACKING BIT(9)
> +#define XE_BO_SCANOUT_BIT BIT(10)
> +#define XE_BO_FIXED_PLACEMENT_BIT BIT(11)
> /* this one is trigger internally only */
> #define XE_BO_INTERNAL_TEST BIT(30)
> #define XE_BO_INTERNAL_64K BIT(31)
> diff --git a/drivers/gpu/drm/xe/xe_pt.c b/drivers/gpu/drm/xe/xe_pt.c
> index f15282996c3b..30de6e902a8e 100644
> --- a/drivers/gpu/drm/xe/xe_pt.c
> +++ b/drivers/gpu/drm/xe/xe_pt.c
> @@ -219,7 +219,8 @@ struct xe_pt *xe_pt_create(struct xe_vm *vm, struct xe_gt *gt,
> ttm_bo_type_kernel,
> XE_BO_CREATE_VRAM_IF_DGFX(gt) |
> XE_BO_CREATE_IGNORE_MIN_PAGE_SIZE_BIT |
> - XE_BO_CREATE_PINNED_BIT);
> + XE_BO_CREATE_PINNED_BIT |
> + XE_BO_CREATE_NO_RESV_EVICT);
> if (IS_ERR(bo)) {
> err = PTR_ERR(bo);
> goto err_kfree;
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