linux-kernel - Re: [PATCH 1/6] drivers: base: devres: Allow to release group on device release

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Message-ID: <ky3kd4rwuwm6lehmb3n7bplnaoxiwuje67q6m7tvuz6vt7bnnb@lool6xnskx32>
Date: Thu, 20 Feb 2025 17:48:10 -0600
From: Lucas De Marchi <lucas.demarchi@...el.com>
To: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
CC: <linux-kernel@...r.kernel.org>, Rodrigo Vivi <rodrigo.vivi@...el.com>,
	<dri-devel@...ts.freedesktop.org>, Danilo Krummrich <dakr@...nel.org>,
	"Rafael J. Wysocki" <rafael@...nel.org>
Subject: Re: [PATCH 1/6] drivers: base: devres: Allow to release group on
 device release

On Thu, Feb 20, 2025 at 01:24:20PM +0100, Greg Kroah-Hartman wrote:
>On Wed, Feb 12, 2025 at 12:05:37PM -0800, Lucas De Marchi wrote:
>> When releasing a device, if the release action causes a group to be
>> released, a warning is emitted because it can't find the group. This
>> happens because devres_release_all() moves the entire list to a todo
>> list and also move the group markers. Considering r* normal resource
>> nodes and g1 a group resource node:
>>
>> 		    g1 -----------.
>> 		    v		  v
>> 	r1 -> r2 -> g1[0] -> r3-> g[1] -> r4
>>
>> After devres_release_all(), dev->devres_head becomes empty and the todo
>> list it iterates on becomes:
>>
>> 			       g1
>> 			       v
>> 	r1 -> r2 -> r3-> r4 -> g1[0]
>>
>> When a call to component_del() is made and takes down the aggregate
>> device, a warning like this happen:
>>
>> 	RIP: 0010:devres_release_group+0x362/0x530
>> 	...
>> 	Call Trace:
>> 	 <TASK>
>> 	 component_unbind+0x156/0x380
>> 	 component_unbind_all+0x1d0/0x270
>> 	 mei_component_master_unbind+0x28/0x80 [mei_hdcp]
>> 	 take_down_aggregate_device+0xc1/0x160
>> 	 component_del+0x1c6/0x3e0
>> 	 intel_hdcp_component_fini+0xf1/0x170 [xe]
>> 	 xe_display_fini+0x1e/0x40 [xe]
>>
>> Because the devres group corresponding to the hdcp component cannot be
>> found. Just ignore this corner case: if the dev->devres_head is empty
>> and the caller is trying to remove a group, it's likely in the process
>> of device cleanup so just ignore it instead of warning.
>>
>> Signed-off-by: Lucas De Marchi <lucas.demarchi@...el.com>
>> ---
>
>Acked-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

Thanks. Is it ok to take these 3 through the drm tree or are you taking
it through yours?

Lucas De Marchi