linux-kernel - Re: 2.6.21-rc suspend regression: sysfs deadlock

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Date:	Wed, 7 Mar 2007 10:56:22 -0500
From:	"Dmitry Torokhov" <dmitry.torokhov@...il.com>
To:	"Linus Torvalds" <torvalds@...ux-foundation.org>
Cc:	"Hugh Dickins" <hugh@...itas.com>,
	"Oliver Neukum" <oliver@...kum.name>,
	"Maneesh Soni" <maneesh@...ibm.com>,
	"Greg Kroah-Hartman" <gregkh@...e.de>,
	"Adrian Bunk" <bunk@...sta.de>, linux-kernel@...r.kernel.org
Subject: Re: 2.6.21-rc suspend regression: sysfs deadlock

On 3/6/07, Linus Torvalds <torvalds@...ux-foundation.org> wrote:
>
>  - removing the buffer is now just
>
>        mutex_lock(&inode->i_mutex);
>        buffer = inode->i_private;
>        inode->i_private = NULL;
>        mutex_unlock(&inode->i_mutex);
>
>        put_sysfs_buffer(buffer);
>
>  - everybody is happy!
>

... with the exception that it will again make data associated with
sysfs attributes accessible past the point of returning from
sysfs_remove_file. And that was the point so drivers would not have to
care about handling access to extra data (such as static strings) past
the driver unload.

I wonder if we should keep Oliver's change and require attribute
implementations to offload "delete me" kind of actions to workqueues.

-- 
Dmitry
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