On 11/04/2022 13:39, Christian König wrote:
Am 11.04.22 um 10:56 schrieb Matthew Auld:If we hit the sync case, like when skipping clearing for kernel internal objects, or when falling back to cpu clearing, like in i915, we end up trying to add a NULL fence, but with some recent changes in this area this now just results in NULL deref in dma_resv_add_fence:<1>[ 5.466383] BUG: kernel NULL pointer dereference, address: 0000000000000008<1>[ 5.466384] #PF: supervisor read access in kernel mode <1>[ 5.466385] #PF: error_code(0x0000) - not-present page <6>[ 5.466386] PGD 0 P4D 0 <4>[ 5.466387] Oops: 0000 [#1] PREEMPT SMP NOPTI<4>[ 5.466389] CPU: 5 PID: 267 Comm: modprobe Not tainted 5.18.0-rc2-CI-CI_DRM_11481+ #1<4>[ 5.466391] RIP: 0010:dma_resv_add_fence+0x63/0x260<4>[ 5.466395] Code: 38 85 c0 0f 84 df 01 00 00 0f 88 e8 01 00 00 83 c0 01 0f 88 df 01 00 00 8b 05 35 89 10 01 49 8d 5e 68 85 c0 0f 85 45 01 00 00 <48> 8b 45 08 48 3d c0 a5 0a 82 0f 84 5c 01 00 00 48 3d 60 a5 0a 82<4>[ 5.466396] RSP: 0018:ffffc90000e974f8 EFLAGS: 00010202<4>[ 5.466397] RAX: 0000000000000001 RBX: ffff888123e88b28 RCX: 00000000ffffffff <4>[ 5.466398] RDX: 0000000000000001 RSI: ffffffff822e4f50 RDI: ffffffff8233f087 <4>[ 5.466399] RBP: 0000000000000000 R08: ffff8881313dbc80 R09: 0000000000000001 <4>[ 5.466399] R10: 0000000000000001 R11: 00000000da354294 R12: 0000000000000000 <4>[ 5.466400] R13: ffff88810927dc58 R14: ffff888123e88ac0 R15: ffff88810a88d600 <4>[ 5.466401] FS: 00007f5fa1193540(0000) GS:ffff88845d880000(0000) knlGS:0000000000000000<4>[ 5.466402] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033<4>[ 5.466402] CR2: 0000000000000008 CR3: 0000000106dd6003 CR4: 00000000003706e0 <4>[ 5.466403] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 <4>[ 5.466404] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400<4>[ 5.466404] Call Trace: <4>[ 5.466405] <TASK> <4>[ 5.466406] ttm_bo_move_accel_cleanup+0x62/0x270 [ttm] <4>[ 5.466411] ? i915_rsgt_from_buddy_resource+0x185/0x1e0 [i915] <4>[ 5.466529] i915_ttm_move+0xfd/0x430 [i915] <4>[ 5.466833] ? dma_resv_reserve_fences+0x4e/0x320 <4>[ 5.466836] ? ttm_bo_add_move_fence.constprop.20+0xf7/0x140 [ttm] <4>[ 5.466841] ttm_bo_handle_move_mem+0xa1/0x140 [ttm] <4>[ 5.466845] ttm_bo_validate+0xee/0x160 [ttm] <4>[ 5.466849] __i915_ttm_get_pages+0x4f/0x210 [i915] <4>[ 5.466976] i915_ttm_get_pages+0xad/0x140 [i915] <4>[ 5.467094] ____i915_gem_object_get_pages+0x32/0xf0 [i915] <4>[ 5.467210] __i915_gem_object_get_pages+0x89/0xa0 [i915] <4>[ 5.467323] i915_vma_get_pages+0x114/0x1d0 [i915] <4>[ 5.467446] i915_vma_pin_ww+0xd3/0xa90 [i915] <4>[ 5.467570] i915_vma_pin.constprop.10+0x119/0x1b0 [i915] <4>[ 5.467700] ? __mutex_unlock_slowpath+0x3e/0x2b0<4>[ 5.467704] intel_alloc_initial_plane_obj.isra.6+0x1a9/0x390 [i915]<4>[ 5.467833] intel_crtc_initial_plane_config+0x83/0x340 [i915] In the ttm_bo_move_sync_cleanup() case it seems we only really care about calling ttm_bo_wait_free_node(), so let's instead just call that directly. Signed-off-by: Matthew Auld <matthew.auld@xxxxxxxxx> Cc: Thomas Hellström <thomas.hellstrom@xxxxxxxxxxxxxxx> Cc: Christian König <christian.koenig@xxxxxxx> Cc: Lucas De Marchi <lucas.demarchi@xxxxxxxxx> Cc: Nirmoy Das <nirmoy.das@xxxxxxxxxxxxxxx>Ideally we wouldn't export that to drivers, but that's a different problem. Reviewed-by: Christian König <christian.koenig@xxxxxxx>
Thanks. Would you be able to merge this?
--- drivers/gpu/drm/ttm/ttm_bo_util.c | 15 +++++++++++++++ include/drm/ttm/ttm_bo_driver.h | 11 +++-------- 2 files changed, 18 insertions(+), 8 deletions(-)diff --git a/drivers/gpu/drm/ttm/ttm_bo_util.c b/drivers/gpu/drm/ttm/ttm_bo_util.cindex bc5190340b9c..1cbfb00c1d65 100644 --- a/drivers/gpu/drm/ttm/ttm_bo_util.c +++ b/drivers/gpu/drm/ttm/ttm_bo_util.c@@ -572,6 +572,21 @@ int ttm_bo_move_accel_cleanup(struct ttm_buffer_object *bo,} EXPORT_SYMBOL(ttm_bo_move_accel_cleanup); +void ttm_bo_move_sync_cleanup(struct ttm_buffer_object *bo, + struct ttm_resource *new_mem) +{ + struct ttm_device *bdev = bo->bdev;+ struct ttm_resource_manager *man = ttm_manager_type(bdev, new_mem->mem_type);+ int ret; + + ret = ttm_bo_wait_free_node(bo, man->use_tt); + if (WARN_ON(ret)) + return; + + ttm_bo_assign_mem(bo, new_mem); +} +EXPORT_SYMBOL(ttm_bo_move_sync_cleanup); + /** * ttm_bo_pipeline_gutting - purge the contents of a bo * @bo: The buffer objectdiff --git a/include/drm/ttm/ttm_bo_driver.h b/include/drm/ttm/ttm_bo_driver.hindex 059a595e14e5..897b88f0bd59 100644 --- a/include/drm/ttm/ttm_bo_driver.h +++ b/include/drm/ttm/ttm_bo_driver.h@@ -245,7 +245,7 @@ int ttm_bo_move_accel_cleanup(struct ttm_buffer_object *bo,struct ttm_resource *new_mem); /** - * ttm_bo_move_accel_cleanup. + * ttm_bo_move_sync_cleanup. * * @bo: A pointer to a struct ttm_buffer_object. * @new_mem: struct ttm_resource indicating where to move.@@ -253,13 +253,8 @@ int ttm_bo_move_accel_cleanup(struct ttm_buffer_object *bo,* Special case of ttm_bo_move_accel_cleanup where the bo is guaranteed * by the caller to be idle. Typically used after memcpy buffer moves. */-static inline void ttm_bo_move_sync_cleanup(struct ttm_buffer_object *bo,- struct ttm_resource *new_mem) -{ - int ret = ttm_bo_move_accel_cleanup(bo, NULL, true, false, new_mem); - - WARN_ON(ret); -} +void ttm_bo_move_sync_cleanup(struct ttm_buffer_object *bo, + struct ttm_resource *new_mem); /** * ttm_bo_pipeline_gutting.
