[PATCH] drm/amdgpu: Do not move root PT bo to relocated list

[Pan, Xinhui]

hit panic when we update the page tables.

<1>[  122.103290] BUG: kernel NULL pointer dereference, address: 0000000000000008
<1>[  122.103348] #PF: supervisor read access in kernel mode
<1>[  122.103376] #PF: error_code(0x0000) - not-present page
<6>[  122.103403] PGD 0 P4D 0 
<4>[  122.103421] Oops: 0000 [#1] SMP PTI
<4>[  122.103442] CPU: 13 PID: 2133 Comm: kfdtest Tainted: G           OE     5.4.0-rc7+ #7
<4>[  122.103480] Hardware name: Supermicro SYS-7048GR-TR/X10DRG-Q, BIOS 3.0b 03/09/2018
<4>[  122.103657] RIP: 0010:amdgpu_vm_update_pdes+0x140/0x330 [amdgpu]
<4>[  122.103689] Code: 03 4c 89 73 08 49 89 9d c8 00 00 00 48 8b 7b f0 c6 43 10 00 45 31 c0 48 8b 87 28 04 00 00 48 85 c0 74 07 4c 8b 80 20 04 00 00 <4d> 8b 70 08 31 f6 49 8b 86 28 04 00 00 48 85 c0 74 0f 48 8b 80 28
<4>[  122.103769] RSP: 0018:ffffb49a0a6a3a98 EFLAGS: 00010246
<4>[  122.103797] RAX: 0000000000000000 RBX: ffff9020f823c148 RCX: dead000000000122
<4>[  122.103831] RDX: ffff9020ece70018 RSI: ffff9020f823c0c8 RDI: ffff9010ca31c800
<4>[  122.103865] RBP: ffffb49a0a6a3b38 R08: 0000000000000000 R09: 0000000000000001
<4>[  122.103899] R10: 000000006044f994 R11: 00000000df57fb58 R12: ffff9020f823c000
<4>[  122.103933] R13: ffff9020f823c000 R14: ffff9020f823c0c8 R15: ffff9010d5d20000
<4>[  122.103968] FS:  00007f32c83dc780(0000) GS:ffff9020ff380000(0000) knlGS:0000000000000000
<4>[  122.104006] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
<4>[  122.104035] CR2: 0000000000000008 CR3: 0000002036bba005 CR4: 00000000003606e0
<4>[  122.104069] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
<4>[  122.104103] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
<4>[  122.104137] Call Trace:
<4>[  122.104241]  vm_update_pds+0x31/0x50 [amdgpu]
<4>[  122.104347]  amdgpu_amdkfd_gpuvm_map_memory_to_gpu+0x2ef/0x690 [amdgpu]
<4>[  122.104466]  kfd_process_alloc_gpuvm+0x98/0x190 [amdgpu]
<4>[  122.104576]  kfd_process_device_init_vm.part.8+0xf3/0x1f0 [amdgpu]
<4>[  122.104688]  kfd_process_device_init_vm+0x24/0x30 [amdgpu]
<4>[  122.104794]  kfd_ioctl_acquire_vm+0xa4/0xc0 [amdgpu]
<4>[  122.104900]  kfd_ioctl+0x277/0x500 [amdgpu]
<4>[  122.105001]  ? kfd_ioctl_free_memory_of_gpu+0xc0/0xc0 [amdgpu]
<4>[  122.105039]  ? rcu_read_lock_sched_held+0x4f/0x80
<4>[  122.105068]  ? kmem_cache_free+0x2ba/0x300
<4>[  122.105093]  ? vm_area_free+0x18/0x20
<4>[  122.105117]  ? find_held_lock+0x35/0xa0
<4>[  122.105143]  do_vfs_ioctl+0xa9/0x6f0
<4>[  122.106001]  ksys_ioctl+0x75/0x80
<4>[  122.106802]  ? do_syscall_64+0x17/0x230
<4>[  122.107605]  __x64_sys_ioctl+0x1a/0x20
<4>[  122.108378]  do_syscall_64+0x5f/0x230
<4>[  122.109118]  entry_SYSCALL_64_after_hwframe+0x49/0xbe
<4>[  122.109842] RIP: 0033:0x7f32c6b495d7

Signed-off-by: xinhui pan <xinhui.pan at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
index 3195bc90985a..3c388fdf335c 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
@@ -2619,7 +2619,7 @@ void amdgpu_vm_bo_invalidate(struct amdgpu_device *adev,
 			continue;
 		bo_base->moved = true;
 
-		if (bo->tbo.type == ttm_bo_type_kernel)
+		if (bo->tbo.type == ttm_bo_type_kernel && bo->parent)
 			amdgpu_vm_bo_relocated(bo_base);
 		else if (bo->tbo.base.resv == vm->root.base.bo->tbo.base.resv)
 			amdgpu_vm_bo_moved(bo_base);
-- 
2.17.1