Re: [PATCH v4 1/3] drm/drm_ras: Add drm_ras netlink error event

["Tauro, Riana" <riana.tauro@intel.com>]

On 09-07-2026 01:51, Rodrigo Vivi wrote:
> On Tue, Jul 07, 2026 at 12:02:11PM +0530, Tauro, Riana wrote:
>> Hi Rodrigo/Jakub/Aravind
>>
>> Please let me know if you have any feedback for this patch or can you please
>> ack this if it looks good to you.
> I looks good to me, but could you please double check the sashiko's comments?

Sashiko has a comment regarding namespaces

[Severity: Medium]Since the generic netlink family explicitly supports 
multiple networknamespaces by setting .netnsok = true,
  will hardcoding init_net hereprevent listeners in non-init namespaces 
from receiving error events

.netnsok = true is auto generated not explicitly added in code.

But from what i see, drm device is present in the host and not 
replicated across namespaces
and most of the non-network implementations use inet.  (ex: Binder)
If this really needs a fix, we can drop the has_listeners suggested by 
raag  in previous patch.
I don't think in an error path, allocating a new buffer would be a big 
overhead if listeners are not present.

@Raag let me know your thoughts.

The 3rd patch can be floated seperately, I can drop it before merging 
and resend if i can get an ack for this
patch

Thanks
Riana



>
> Patch 3 still needs review I believe, then we get Jakub and drm maintainers acks
> to get this through drm-xe-next.
>
> Thanks,
> Rodrigo.
>
>> Thanks
>> Riana
>>
>> On 01-07-2026 15:14, Riana Tauro wrote:
>>> Define a new netlink event 'error-event' and a new multicast group
>>> 'error-report' in drm_ras. Each event contains device name, node and
>>> error information to identify the error triggering the event.
>>>
>>> Add drm_ras_nl_error_event() to trigger an event from the driver.
>>> Userspace must subscribe to 'error-report' to receive 'error-event'
>>> notifications.
>>>
>>> Usage:
>>>
>>> $ sudo ynl --family drm_ras --subscribe error-report
>>>
>>> Cc: Jakub Kicinski <kuba@kernel.org>
>>> Cc: Zack McKevitt <zachary.mckevitt@oss.qualcomm.com>
>>> Cc: Lijo Lazar <lijo.lazar@amd.com>
>>> Cc: Hawking Zhang <Hawking.Zhang@amd.com>
>>> Cc: David S. Miller <davem@davemloft.net>
>>> Cc: Paolo Abeni <pabeni@redhat.com>
>>> Cc: Eric Dumazet <edumazet@google.com>
>>> Signed-off-by: Riana Tauro <riana.tauro@intel.com>
>>> Reviewed-by: Raag Jadav <raag.jadav@intel.com>
>>> ---
>>> v2: remove redundant initialization
>>>       remove unnecessary space
>>>       use ynl in commit message and doc (Raag)
>>>       simplify doc for error-event attrs
>>>
>>> v3: rename error-notify to error-report
>>>       Replace notify with report across the file (Raag)
>>> ---
>>>    Documentation/gpu/drm-ras.rst            | 21 ++++++
>>>    Documentation/netlink/specs/drm_ras.yaml | 48 +++++++++++++
>>>    drivers/gpu/drm/drm_ras.c                | 87 ++++++++++++++++++++++++
>>>    drivers/gpu/drm/drm_ras_nl.c             |  6 ++
>>>    drivers/gpu/drm/drm_ras_nl.h             |  4 ++
>>>    include/drm/drm_ras.h                    |  5 ++
>>>    include/uapi/drm/drm_ras.h               | 15 ++++
>>>    7 files changed, 186 insertions(+)
>>>
>>> diff --git a/Documentation/gpu/drm-ras.rst b/Documentation/gpu/drm-ras.rst
>>> index 83c21853b74b..406e4c49bac1 100644
>>> --- a/Documentation/gpu/drm-ras.rst
>>> +++ b/Documentation/gpu/drm-ras.rst
>>> @@ -56,6 +56,7 @@ User space tools can:
>>>      ``node-id`` and ``error-id`` as parameters.
>>>    * Clear specific error counters with the ``clear-error-counter`` command, using both
>>>      ``node-id`` and ``error-id`` as parameters.
>>> +* Subscribe to the ``error-report`` multicast group to receive ``error-event``.
>>>    YAML-based Interface
>>>    --------------------
>>> @@ -111,3 +112,23 @@ Example: Clear an error counter for a given node
>>>        sudo ynl --family drm_ras --do clear-error-counter --json '{"node-id":0, "error-id":1}'
>>>        None
>>> +
>>> +Example: Subscribe to ``error-report`` multicast group
>>> +
>>> +.. code-block:: bash
>>> +
>>> +    sudo ynl --family drm_ras --output-json --subscribe error-report
>>> +
>>> +.. code-block:: json
>>> +
>>> +    {
>>> +        "name": "error-event",
>>> +        "msg": {
>>> +            "device-name": "0000:03:00.0",
>>> +            "node-id": 1,
>>> +            "node-name": "uncorrectable-errors",
>>> +            "error-id": 1,
>>> +            "error-name": "error_name1",
>>> +            "error-value": 1
>>> +        }
>>> +    }
>>> diff --git a/Documentation/netlink/specs/drm_ras.yaml b/Documentation/netlink/specs/drm_ras.yaml
>>> index e113056f8c01..8aed3d4515e5 100644
>>> --- a/Documentation/netlink/specs/drm_ras.yaml
>>> +++ b/Documentation/netlink/specs/drm_ras.yaml
>>> @@ -69,6 +69,33 @@ attribute-sets:
>>>            name: error-value
>>>            type: u32
>>>            doc: Current value of the requested error counter.
>>> +  -
>>> +    name: error-event-attrs
>>> +    attributes:
>>> +      -
>>> +        name: device-name
>>> +        type: string
>>> +        doc: Device (PCI BDF, UUID) that reported the error.
>>> +      -
>>> +        name: node-id
>>> +        type: u32
>>> +        doc: ID of the node that reported the error.
>>> +      -
>>> +        name: node-name
>>> +        type: string
>>> +        doc: Name of the node that reported the error.
>>> +      -
>>> +        name: error-id
>>> +        type: u32
>>> +        doc: ID of the error counter.
>>> +      -
>>> +        name: error-name
>>> +        type: string
>>> +        doc: Name of the error.
>>> +      -
>>> +        name: error-value
>>> +        type: u32
>>> +        doc: Current value of the error counter.
>>>    operations:
>>>      list:
>>> @@ -124,3 +151,24 @@ operations:
>>>          do:
>>>            request:
>>>              attributes: *id-attrs
>>> +    -
>>> +      name: error-event
>>> +      doc: >-
>>> +           Report an error event to userspace.
>>> +           The event includes the device, node and error information
>>> +           of the error that triggered the event.
>>> +      attribute-set: error-event-attrs
>>> +      mcgrp: error-report
>>> +      event:
>>> +        attributes:
>>> +          - device-name
>>> +          - node-id
>>> +          - node-name
>>> +          - error-id
>>> +          - error-name
>>> +          - error-value
>>> +
>>> +mcast-groups:
>>> +  list:
>>> +    -
>>> +      name: error-report
>>> diff --git a/drivers/gpu/drm/drm_ras.c b/drivers/gpu/drm/drm_ras.c
>>> index d6eab29a1394..77f912a4d101 100644
>>> --- a/drivers/gpu/drm/drm_ras.c
>>> +++ b/drivers/gpu/drm/drm_ras.c
>>> @@ -41,6 +41,11 @@
>>>     *    Userspace must provide Node ID, Error ID.
>>>     *    Clears specific error counter of a node if supported.
>>>     *
>>> + * 4. ERROR_REPORT: Subscribe to this multicast group to receive error events
>>> + *
>>> + * 5. ERROR_EVENT: Report an error event to userspace. The event contains device, node
>>> + *    and error information that triggered the event.
>>> + *
>>>     * Node registration:
>>>     *
>>>     * - drm_ras_node_register(): Registers a new node and assigns
>>> @@ -186,6 +191,34 @@ static int msg_reply_value(struct sk_buff *msg, u32 error_id,
>>>    			   value);
>>>    }
>>> +static int msg_put_error_event_attrs(struct sk_buff *msg, struct drm_ras_node *node,
>>> +				     u32 error_id, const char *error_name, u32 value)
>>> +{
>>> +	int ret;
>>> +
>>> +	ret = nla_put_string(msg, DRM_RAS_A_ERROR_EVENT_ATTRS_DEVICE_NAME, node->device_name);
>>> +	if (ret)
>>> +		return ret;
>>> +
>>> +	ret = nla_put_u32(msg, DRM_RAS_A_ERROR_EVENT_ATTRS_NODE_ID, node->id);
>>> +	if (ret)
>>> +		return ret;
>>> +
>>> +	ret = nla_put_string(msg, DRM_RAS_A_ERROR_EVENT_ATTRS_NODE_NAME, node->node_name);
>>> +	if (ret)
>>> +		return ret;
>>> +
>>> +	ret = nla_put_u32(msg, DRM_RAS_A_ERROR_EVENT_ATTRS_ERROR_ID, error_id);
>>> +	if (ret)
>>> +		return ret;
>>> +
>>> +	ret = nla_put_string(msg, DRM_RAS_A_ERROR_EVENT_ATTRS_ERROR_NAME, error_name);
>>> +	if (ret)
>>> +		return ret;
>>> +
>>> +	return nla_put_u32(msg, DRM_RAS_A_ERROR_EVENT_ATTRS_ERROR_VALUE, value);
>>> +}
>>> +
>>>    static int doit_reply_value(struct genl_info *info, u32 node_id,
>>>    			    u32 error_id)
>>>    {
>>> @@ -222,6 +255,60 @@ static int doit_reply_value(struct genl_info *info, u32 node_id,
>>>    	return genlmsg_reply(msg, info);
>>>    }
>>> +/**
>>> + * drm_ras_nl_error_event() - Report an error event
>>> + * @node: Node structure
>>> + * @error_id: ID of the error
>>> + * @error_name: Name of the error
>>> + * @value: Value associated with the error
>>> + * @flags: GFP flags for memory allocation
>>> + *
>>> + * Report an error-event to userspace using the error-report multicast group.
>>> + *
>>> + * Return: 0 on success, or negative errno on failure.
>>> + */
>>> +int drm_ras_nl_error_event(struct drm_ras_node *node, u32 error_id, const char *error_name,
>>> +			   u32 value, gfp_t flags)
>>> +{
>>> +	struct genl_info info;
>>> +	struct sk_buff *msg;
>>> +	struct nlattr *hdr;
>>> +	int ret;
>>> +
>>> +	if (!error_name)
>>> +		return -EINVAL;
>>> +
>>> +	if (!genl_has_listeners(&drm_ras_nl_family, &init_net, DRM_RAS_NLGRP_ERROR_REPORT))
>>> +		return 0;
>>> +
>>> +	genl_info_init_ntf(&info, &drm_ras_nl_family, DRM_RAS_CMD_ERROR_EVENT);
>>> +
>>> +	msg = genlmsg_new(NLMSG_GOODSIZE, flags);
>>> +	if (!msg)
>>> +		return -ENOMEM;
>>> +
>>> +	hdr = genlmsg_iput(msg, &info);
>>> +	if (!hdr) {
>>> +		ret = -EMSGSIZE;
>>> +		goto free_msg;
>>> +	}
>>> +
>>> +	ret = msg_put_error_event_attrs(msg, node, error_id, error_name, value);
>>> +	if (ret)
>>> +		goto cancel_msg;
>>> +
>>> +	genlmsg_end(msg, hdr);
>>> +	genlmsg_multicast(&drm_ras_nl_family, msg, 0, DRM_RAS_NLGRP_ERROR_REPORT, flags);
>>> +	return 0;
>>> +
>>> +cancel_msg:
>>> +	genlmsg_cancel(msg, hdr);
>>> +free_msg:
>>> +	nlmsg_free(msg);
>>> +	return ret;
>>> +}
>>> +EXPORT_SYMBOL(drm_ras_nl_error_event);
>>> +
>>>    /**
>>>     * drm_ras_nl_get_error_counter_dumpit() - Dump all Error Counters
>>>     * @skb: Netlink message buffer
>>> diff --git a/drivers/gpu/drm/drm_ras_nl.c b/drivers/gpu/drm/drm_ras_nl.c
>>> index dea1c1b2494e..9d3123cc9f9c 100644
>>> --- a/drivers/gpu/drm/drm_ras_nl.c
>>> +++ b/drivers/gpu/drm/drm_ras_nl.c
>>> @@ -58,6 +58,10 @@ static const struct genl_split_ops drm_ras_nl_ops[] = {
>>>    	},
>>>    };
>>> +static const struct genl_multicast_group drm_ras_nl_mcgrps[] = {
>>> +	[DRM_RAS_NLGRP_ERROR_REPORT] = { "error-report", },
>>> +};
>>> +
>>>    struct genl_family drm_ras_nl_family __ro_after_init = {
>>>    	.name		= DRM_RAS_FAMILY_NAME,
>>>    	.version	= DRM_RAS_FAMILY_VERSION,
>>> @@ -66,4 +70,6 @@ struct genl_family drm_ras_nl_family __ro_after_init = {
>>>    	.module		= THIS_MODULE,
>>>    	.split_ops	= drm_ras_nl_ops,
>>>    	.n_split_ops	= ARRAY_SIZE(drm_ras_nl_ops),
>>> +	.mcgrps		= drm_ras_nl_mcgrps,
>>> +	.n_mcgrps	= ARRAY_SIZE(drm_ras_nl_mcgrps),
>>>    };
>>> diff --git a/drivers/gpu/drm/drm_ras_nl.h b/drivers/gpu/drm/drm_ras_nl.h
>>> index a398643572a5..03ec275aca92 100644
>>> --- a/drivers/gpu/drm/drm_ras_nl.h
>>> +++ b/drivers/gpu/drm/drm_ras_nl.h
>>> @@ -21,6 +21,10 @@ int drm_ras_nl_get_error_counter_dumpit(struct sk_buff *skb,
>>>    int drm_ras_nl_clear_error_counter_doit(struct sk_buff *skb,
>>>    					struct genl_info *info);
>>> +enum {
>>> +	DRM_RAS_NLGRP_ERROR_REPORT,
>>> +};
>>> +
>>>    extern struct genl_family drm_ras_nl_family;
>>>    #endif /* _LINUX_DRM_RAS_GEN_H */
>>> diff --git a/include/drm/drm_ras.h b/include/drm/drm_ras.h
>>> index 0beede3ddc4e..8abfb7d2077b 100644
>>> --- a/include/drm/drm_ras.h
>>> +++ b/include/drm/drm_ras.h
>>> @@ -80,9 +80,14 @@ struct drm_device;
>>>    #if IS_ENABLED(CONFIG_DRM_RAS)
>>>    int drm_ras_node_register(struct drm_ras_node *node);
>>>    void drm_ras_node_unregister(struct drm_ras_node *node);
>>> +int drm_ras_nl_error_event(struct drm_ras_node *node, u32 error_id, const char *error_name,
>>> +			   u32 value, gfp_t flags);
>>>    #else
>>>    static inline int drm_ras_node_register(struct drm_ras_node *node) { return 0; }
>>>    static inline void drm_ras_node_unregister(struct drm_ras_node *node) { }
>>> +static inline int drm_ras_nl_error_event(struct drm_ras_node *node, u32 error_id,
>>> +					 const char *error_name, u32 value, gfp_t flags)
>>> +{ return 0; }
>>>    #endif
>>>    #endif
>>> diff --git a/include/uapi/drm/drm_ras.h b/include/uapi/drm/drm_ras.h
>>> index 218a3ee86805..eab8231aa87c 100644
>>> --- a/include/uapi/drm/drm_ras.h
>>> +++ b/include/uapi/drm/drm_ras.h
>>> @@ -38,13 +38,28 @@ enum {
>>>    	DRM_RAS_A_ERROR_COUNTER_ATTRS_MAX = (__DRM_RAS_A_ERROR_COUNTER_ATTRS_MAX - 1)
>>>    };
>>> +enum {
>>> +	DRM_RAS_A_ERROR_EVENT_ATTRS_DEVICE_NAME = 1,
>>> +	DRM_RAS_A_ERROR_EVENT_ATTRS_NODE_ID,
>>> +	DRM_RAS_A_ERROR_EVENT_ATTRS_NODE_NAME,
>>> +	DRM_RAS_A_ERROR_EVENT_ATTRS_ERROR_ID,
>>> +	DRM_RAS_A_ERROR_EVENT_ATTRS_ERROR_NAME,
>>> +	DRM_RAS_A_ERROR_EVENT_ATTRS_ERROR_VALUE,
>>> +
>>> +	__DRM_RAS_A_ERROR_EVENT_ATTRS_MAX,
>>> +	DRM_RAS_A_ERROR_EVENT_ATTRS_MAX = (__DRM_RAS_A_ERROR_EVENT_ATTRS_MAX - 1)
>>> +};
>>> +
>>>    enum {
>>>    	DRM_RAS_CMD_LIST_NODES = 1,
>>>    	DRM_RAS_CMD_GET_ERROR_COUNTER,
>>>    	DRM_RAS_CMD_CLEAR_ERROR_COUNTER,
>>> +	DRM_RAS_CMD_ERROR_EVENT,
>>>    	__DRM_RAS_CMD_MAX,
>>>    	DRM_RAS_CMD_MAX = (__DRM_RAS_CMD_MAX - 1)
>>>    };
>>> +#define DRM_RAS_MCGRP_ERROR_REPORT	"error-report"
>>> +
>>>    #endif /* _UAPI_LINUX_DRM_RAS_H */