[PATCH 1/2] drm/amdgpu: Fixed the defect of soft lock caused by infinite loop

Zhou1, Tao Tao.Zhou1 at amd.com
Sun Jan 30 03:19:30 UTC 2022


[AMD Official Use Only]



> -----Original Message-----
> From: Chai, Thomas <YiPeng.Chai at amd.com>
> Sent: Saturday, January 29, 2022 8:34 PM
> To: amd-gfx at lists.freedesktop.org
> Cc: Chai, Thomas <YiPeng.Chai at amd.com>; Zhang, Hawking
> <Hawking.Zhang at amd.com>; Zhou1, Tao <Tao.Zhou1 at amd.com>; Clements,
> John <John.Clements at amd.com>; Chai, Thomas <YiPeng.Chai at amd.com>
> Subject: [PATCH 1/2] drm/amdgpu: Fixed the defect of soft lock caused by
> infinite loop
> 
> 1. The infinite loop case only occurs on multiple cards support
>    ras functions.
> 2. The explanation of root cause refer to 76641cbbf196523b5752c6cf68f86.
> 3. Create new node to manage each unique ras instance to guarantee
>    each device .ras_list is completely independent.
> 4. Fixes:7a6b8ab3231b511915cb94cac1debabf093.
> 5. The soft locked logs are as follows:
> [  262.165690] CPU: 93 PID: 758 Comm: kworker/93:1 Tainted: G           OE
> 5.13.0-27-generic #29~20.04.1-Ubuntu
> [  262.165695] Hardware name: Supermicro AS -4124GS-TNR/H12DSG-O-CPU,
> BIOS T20200717143848 07/17/2020 [  262.165698] Workqueue: events
> amdgpu_ras_do_recovery [amdgpu] [  262.165980] RIP:
> 0010:amdgpu_ras_get_ras_block+0x86/0xd0 [amdgpu] [  262.166239] Code: 68
> d8 4c 8d 71 d8 48 39 c3 74 54 49 8b 45 38 48 85 c0 74 32 44 89 fa 44 89 e6 4c 89
> ef e8 82 e4 9b dc 85 c0 74 3c 49 8b 46 28 <49> 8d 56 28 4d 89 f5 48 83 e8 28 48
> 39 d3 74 25 49 89 c6 49 8b 45 [  262.166243] RSP: 0018:ffffac908fa87d80
> EFLAGS: 00000202 [  262.166247] RAX: ffffffffc1394248 RBX: ffff91e4ab8d6e20
> RCX: ffffffffc1394248 [  262.166249] RDX: ffff91e4aa356e20 RSI:
> 000000000000000e RDI: ffff91e4ab8c0000 [  262.166252] RBP:
> ffffac908fa87da8 R08: 0000000000000007 R09: 0000000000000001
> [  262.166254] R10: ffff91e4930b64ec R11: 0000000000000000 R12:
> 000000000000000e [  262.166256] R13: ffff91e4aa356df8 R14: ffffffffc1394320
> R15: 0000000000000003 [  262.166258] FS:  0000000000000000(0000)
> GS:ffff92238fb40000(0000) knlGS:0000000000000000 [  262.166261] CS:  0010
> DS: 0000 ES: 0000 CR0: 0000000080050033 [  262.166264] CR2:
> 00000001004865d0 CR3: 000000406d796000 CR4: 0000000000350ee0
> [  262.166267] Call Trace:
> [  262.166272]  amdgpu_ras_do_recovery+0x130/0x290 [amdgpu]
> [  262.166529]  ? psi_task_switch+0xd2/0x250 [  262.166537]  ?
> __switch_to+0x11d/0x460 [  262.166542]  ? __switch_to_asm+0x36/0x70
> [  262.166549]  process_one_work+0x220/0x3c0 [  262.166556]
> worker_thread+0x4d/0x3f0 [  262.166560]  ? process_one_work+0x3c0/0x3c0
> [  262.166563]  kthread+0x12b/0x150 [  262.166568]  ?
> set_kthread_struct+0x40/0x40 [  262.166571]  ret_from_fork+0x22/0x30
> 
> Signed-off-by: yipechai <YiPeng.Chai at amd.com>
> ---
>  drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c | 37 ++++++++++++++++++++++--
> -  drivers/gpu/drm/amd/amdgpu/amdgpu_ras.h |  3 --
>  2 files changed, 33 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c
> b/drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c
> index 9d7c778c1a2d..b0aa67308c31 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c
> @@ -75,6 +75,13 @@ const char *ras_mca_block_string[] = {
>  	"mca_iohc",
>  };
> 
> +struct amdgpu_ras_block_list {
> +	/* ras block link */
> +	struct list_head node;
> +
> +	struct amdgpu_ras_block_object *ras_obj; };
> +
>  const char *get_ras_block_str(struct ras_common_if *ras_block)  {
>  	if (!ras_block)
> @@ -880,7 +887,8 @@ static struct amdgpu_ras_block_object
> *amdgpu_ras_get_ras_block(struct amdgpu_de
>  					enum amdgpu_ras_block block,
> uint32_t sub_block_index)  {
>  	int loop_cnt = 0;
> -	struct amdgpu_ras_block_object *obj, *tmp;
> +	struct amdgpu_ras_block_list *node, *tmp;
> +	struct amdgpu_ras_block_object *obj;
> 
>  	if (block >= AMDGPU_RAS_BLOCK__LAST)
>  		return NULL;
> @@ -888,7 +896,13 @@ static struct amdgpu_ras_block_object
> *amdgpu_ras_get_ras_block(struct amdgpu_de
>  	if (!amdgpu_ras_is_supported(adev, block))
>  		return NULL;
> 
> -	list_for_each_entry_safe(obj, tmp, &adev->ras_list, node) {
> +	list_for_each_entry_safe(node, tmp, &adev->ras_list, node) {
> +		if (!node->ras_obj) {
> +			DRM_ERROR("Warning: abnormal ras list node");
[Tao]: dev_warn is recommended.

> +			continue;
> +		}
> +
> +		obj = node->ras_obj;
>  		if (obj->ras_block_match) {
>  			if (obj->ras_block_match(obj, block, sub_block_index)
> == 0)
>  				return obj;
> @@ -2527,6 +2541,7 @@ int amdgpu_ras_pre_fini(struct amdgpu_device *adev)
> 
>  int amdgpu_ras_fini(struct amdgpu_device *adev)  {
> +	struct amdgpu_ras_block_list *ras_node, *tmp;
>  	struct amdgpu_ras *con = amdgpu_ras_get_context(adev);
> 
>  	if (!adev->ras_enabled || !con)
> @@ -2545,6 +2560,12 @@ int amdgpu_ras_fini(struct amdgpu_device *adev)
>  	amdgpu_ras_set_context(adev, NULL);
>  	kfree(con);
> 
> +	/* Clear ras blocks from ras_list and free ras block list node */
> +	list_for_each_entry_safe(ras_node, tmp, &adev->ras_list, node) {
> +		list_del(&ras_node->node);
> +		kfree(ras_node);
> +	}
> +
>  	return 0;
>  }
> 
> @@ -2754,14 +2775,22 @@ int amdgpu_ras_reset_gpu(struct amdgpu_device
> *adev)  int amdgpu_ras_register_ras_block(struct amdgpu_device *adev,
>  		struct amdgpu_ras_block_object *ras_block_obj)  {
> +	struct amdgpu_ras_block_list *ras_node;
>  	if (!adev || !ras_block_obj)
>  		return -EINVAL;
> 
>  	if (!amdgpu_ras_asic_supported(adev))
>  		return 0;
> 
> -	INIT_LIST_HEAD(&ras_block_obj->node);
> -	list_add_tail(&ras_block_obj->node, &adev->ras_list);
> +	ras_node = kzalloc(sizeof(*ras_node), GFP_KERNEL);
> +	if (!ras_node) {
> +		DRM_ERROR("Failed to allocate ras_node");
[Tao] dev_err is better.

> +		return -EINVAL;
[Tao]: how about return -ENOMEM here?

> +	}
> +
> +	INIT_LIST_HEAD(&ras_node->node);
> +	ras_node->ras_obj = ras_block_obj;
> +	list_add_tail(&ras_node->node, &adev->ras_list);
> 
>  	return 0;
>  }
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ras.h
> b/drivers/gpu/drm/amd/amdgpu/amdgpu_ras.h
> index a51a281bd91a..a55743b12d57 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ras.h
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ras.h
> @@ -493,9 +493,6 @@ struct amdgpu_ras_block_object {
> 
>  	uint32_t sub_block_index;
> 
> -	/* ras block link */
> -	struct list_head node;
> -
>  	int (*ras_block_match)(struct amdgpu_ras_block_object *block_obj,
>  				enum amdgpu_ras_block block, uint32_t
> sub_block_index);
>  	int (*ras_late_init)(struct amdgpu_device *adev, void *ras_info);
> --
> 2.25.1


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