Re: [PATCH 2/6] amdgpu: fix invalid memory access in kfd_cleanup_nodes()

["Chen, Xiaogang" <xiaogang.chen@amd.com>]

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On 1/2/2025 11:55 PM, Gerry Liu wrote:
>
>
>> 2025年1月3日 13:44，Chen, Xiaogang <xiaogang.chen@amd.com> 写道：
>>
>>
>> On 1/2/2025 8:22 PM, Gerry Liu wrote:
>>>
>>>
>>>> 2025年1月3日 07:08，Chen, Xiaogang <xiaogang.chen@amd.com> 写道：
>>>>
>>>>
>>>> On 1/1/2025 11:36 PM, Jiang Liu wrote:
>>>>> On error recover path during device probe, it may trigger invalid
>>>>> memory access as below:
>>>>> 024-12-25 12:00:53 [ 2703.773040] general protection fault, probably for non-canonical address 0x52445f4749464e4f: 0000 [#1] SMP NOPTI
>>>>> 2024-12-25 12:00:53 [ 2703.785199] CPU: 157 PID: 151951 Comm: rmmod Kdump: loaded Tainted: G        W  OE     5.10.134-17.2.al8.x86_64 #1
>>>>> 2024-12-25 12:00:53 [ 2703.797515] Hardware name: Alibaba Alibaba Cloud ECS/Alibaba Cloud ECS, BIOS 3.0.ES.AL.P.087.05 04/07/2024
>>>>> 2024-12-25 12:00:53 [ 2703.809188] RIP: 0010:kgd2kfd_device_exit+0x6/0x60 [amdgpu]
>>>>> 2024-12-25 12:00:53 [ 2703.816136] Code: ff 48 c7 83 38 01 00 00 80 45 e4 c0 c7 83 40 01 00 00 08 0f 00 00 e9 cd fa ff ff 66 0f 1f 84 00 00 00 00 00 0f
>>>>> 1f 44 00 00 55 <80> bf 28 01 00 00 00 48 89 fd 75 09 48 89 ef 5d e9 65 df 9d f4 8b
>>>>> 2024-12-25 12:00:54 [ 2703.838622] RSP: 0018:ffffb5313df07e10 EFLAGS: 00010202
>>>>> 2024-12-25 12:00:54 [ 2703.845216] RAX: 0000000000000000 RBX: ffff97ad689a3ff0 RCX: 0000000080400014
>>>>> 2024-12-25 12:00:54 [ 2703.853935] RDX: 0000000080400015 RSI: ffff97ad627e93d8 RDI: 52445f4749464e4f
>>>>> 2024-12-25 12:00:54 [ 2703.862652] RBP: ffff97ad689a3ff0 R08: 0000000000000000 R09: ffffffffb5814c00
>>>>> 2024-12-25 12:00:54 [ 2703.871368] R10: ffff97ad627e9280 R11: 0000000000000001 R12: ffffb5313df07e98
>>>>> 2024-12-25 12:00:54 [ 2703.880068] R13: ffff97ad689a1810 R14: 0000000000000001 R15: 0000000000000000
>>>>> 2024-12-25 12:00:54 [ 2703.888768] FS:  00007fa4db81e740(0000) GS:ffff98a93ec80000(0000) knlGS:0000000000000000
>>>>> 2024-12-25 12:00:54 [ 2703.898547] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>>>>> 2024-12-25 12:00:54 [ 2703.905684] CR2: 00007f4502deca00 CR3: 000001008fc50001 CR4: 0000000002770ee0
>>>>> 2024-12-25 12:00:54 [ 2703.914382] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
>>>>> 2024-12-25 12:00:54 [ 2703.923066] DR3: 0000000000000000 DR6: 00000000fffe07f0 DR7: 0000000000000400
>>>>> 2024-12-25 12:00:54 [ 2703.931746] PKRU: 55555554
>>>>> 2024-12-25 12:00:54 [ 2703.935444] Call Trace:
>>>>> 2024-12-25 12:00:54 [ 2703.938962]  amdgpu_amdkfd_device_fini_sw+0x1a/0x40 [amdgpu]
>>>>> 2024-12-25 12:00:54 [ 2703.946080]  amdgpu_device_ip_fini.isra.0+0x3d/0x1b0 [amdgpu]
>>>>> 2024-12-25 12:00:54 [ 2703.953278]  amdgpu_device_fini_sw+0x2a/0x240 [amdgpu]
>>>>> 2024-12-25 12:00:54 [ 2703.959789]  amdgpu_driver_release_kms+0x12/0x30 [amdgpu]
>>>>> 2024-12-25 12:00:54 [ 2703.966501]  devm_drm_dev_init_release+0x42/0x70 [drm]
>>>>> 2024-12-25 12:00:54 [ 2703.972891]  release_nodes+0x6e/0xb0
>>>>> 2024-12-25 12:00:54 [ 2703.977522]  amdgpu_xcp_drv_release+0x38/0x80 [amdxcp]
>>>>> 2024-12-25 12:00:54 [ 2703.983906]  __do_sys_delete_module.constprop.0+0x138/0x2a0
>>>>> 2024-12-25 12:00:54 [ 2703.990775]  ? exit_to_user_mode_loop+0xd6/0x120
>>>>> 2024-12-25 12:00:54 [ 2703.996563]  do_syscall_64+0x2e/0x50
>>>>> 2024-12-25 12:00:54 [ 2704.001166]  entry_SYSCALL_64_after_hwframe+0x62/0xc7
>>>>> 2024-12-25 12:00:54 [ 2704.007432] RIP: 0033:0x7fa4db2620cb
>>>>> 2024-12-25 12:00:54 [ 2704.012025] Code: 73 01 c3 48 8b 0d a5 6d 19 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa b8 b0
>>>>> 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 75 6d 19 00 f7 d8 64 89 01 48
>>>>>
>>>>> Signed-off-by: Jiang Liu<gerry@linux.alibaba.com>
>>>>> ---
>>>>>   drivers/gpu/drm/amd/amdkfd/kfd_device.c | 7 ++++++-
>>>>>   1 file changed, 6 insertions(+), 1 deletion(-)
>>>>>
>>>>> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_device.c b/drivers/gpu/drm/amd/amdkfd/kfd_device.c
>>>>> index b6c5ffd4630b..58c1b5fcf785 100644
>>>>> --- a/drivers/gpu/drm/amd/amdkfd/kfd_device.c
>>>>> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_device.c
>>>>> @@ -663,6 +663,8 @@ static void kfd_cleanup_nodes(struct kfd_dev *kfd, unsigned int num_nodes)
>>>>>   
>>>>>   	for (i = 0; i < num_nodes; i++) {
>>>>>   		knode = kfd->nodes[i];
>>>>> +		if (!knode)
>>>>> +			continue;
>>>>
>>>> I wonder how knode can be null here? kfd_cleanup_nodes is called by 
>>>> kgd2kfd_device_exit under condition if (kfd->init_complete). 
>>>> kfd->init_complete is true only after all kfd node got initialized 
>>>> at kgd2kfd_device_init. If kfd driver init fail kfd->init_complete 
>>>> would be false, then kfd_cleanup_node would not get called.
>>>>
>>> Hi Xiaogang,
>>> It may get triggered on error handling path of 
>>> ‘kid2kfd_device_init()`, when it jump to label `node_alloc_error` and
>>> then call `kfd_cleanup_nodes()`.
>>>
>> If it was the case kzalloc failed. That means there is no memory 
>> available even to allocate struct kfd_node. From the backtrace the 
>> general protection fault happened at
>>
>> RIP: 0010:kgd2kfd_device_exit+0x6/0x60 [amdgpu]
>>
>> It happened during driver module got released, not init time. I do not see how the patch is related to the issue you talked.
> Aha, it’s caused by another bug which got fixed by "[PATCH 4/6] 
> amdgpu: fix use after free bug related to amdgpu_driver_release_kms()”.
> Without the fix in "[PATCH 4/6] amdgpu: fix use after free bug related 
> to amdgpu_driver_release_kms()”, kgd2kfd_device_exit() will got called
> twice in case of device probe failure. I caused me some time to figure 
> out the double free issue.
> Actually we should reset kfd->init_completed to false in function 
> kgd2kfd_device_exit().

We can set kfd->init_completed = false at end of kgd2kfd_device_exit, 
but how kgd2kfd_device_exit was called two times? is there another bug 
caused that?

Regards

Xiaogang

>
>> Regards
>> Xiaogang
>>
>>
>>
>>> Thanks,
>>> Gerry
>>>
>>>>
>>>> Regards
>>>>
>>>> Xiaogang
>>>>
>>>>>   		device_queue_manager_uninit(knode->dqm);
>>>>>   		kfd_interrupt_exit(knode);
>>>>>   		kfd_topology_remove_device(knode);
>>>>> @@ -954,7 +956,10 @@ void kgd2kfd_device_exit(struct kfd_dev *kfd)
>>>>>   		kfd_doorbell_fini(kfd);
>>>>>   		ida_destroy(&kfd->doorbell_ida);
>>>>>   		kfd_gtt_sa_fini(kfd);
>>>>> -		amdgpu_amdkfd_free_gtt_mem(kfd->adev, &kfd->gtt_mem);
>>>>> +		if (kfd->gtt_mem) {
>>>>> +			amdgpu_amdkfd_free_gtt_mem(kfd->adev, &kfd->gtt_mem);
>>>>> +			kfd->gtt_mem = NULL;
>>>>> +		}
>>>>>   	}
>>>>>   
>>>>>   	kfree(kfd);
>>>
>

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