Commit fc60bb83 authored Jun 07, 2013 by Nick Dyer Committed by Greg Kroah-Hartman Jun 07, 2013

sysfs_notify is only possible on file attributes



If sysfs_notify is called on a binary attribute, bad things can
happen, so prevent it.

Note, no in-kernel usage of this is currently present, but in the
future, it's good to be safe.

Changes in V2:
- Also ignore sysfs_notify on dirs, links
- Use WARN_ON rather than silently failing
- Compiled and tested (huge apologies about first submission)

Signed-off-by: Nick Dyer <nick.dyer@itdev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent d6c8aa39

fs/sysfs/file.c

+6 −4

Original line number	Original line	Diff line number	Diff line
	@@ -449,11 +449,13 @@ void sysfs_notify_dirent(struct sysfs_dirent *sd)

	spin_lock_irqsave(&sysfs_open_dirent_lock, flags);		spin_lock_irqsave(&sysfs_open_dirent_lock, flags);

			if (!WARN_ON(sysfs_type(sd) != SYSFS_KOBJ_ATTR)) {
	od = sd->s_attr.open;		od = sd->s_attr.open;
	if (od) {		if (od) {
	atomic_inc(&od->event);		atomic_inc(&od->event);
	wake_up_interruptible(&od->poll);		wake_up_interruptible(&od->poll);
	}		}
			}

	spin_unlock_irqrestore(&sysfs_open_dirent_lock, flags);		spin_unlock_irqrestore(&sysfs_open_dirent_lock, flags);
	}		}

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