Re: [PATCH] call_usermodehelper hang

From: Greg KH
Date: Thu Apr 08 2004 - 18:04:45 EST


On Wed, Apr 07, 2004 at 05:58:46PM -0500, Brian King wrote:
> The following patch fixes a deadlock experienced when devices are
> being added to a bus both from a user process and eventd process.
> The eventd process was hung waiting on dev->bus->subsys.rwsem which
> was held by another process, which was hung since it was calling
> call_usermodehelper directly which was hung waiting for work scheduled
> on the eventd workqueue to complete. The patch fixes this by delaying
> the kobject_hotplug work, running it from eventd if possible.

But why? Will this not still cause the same deadlock eventually? The
call_usermodehelper function uses keventd, so what about users who call
that function directly?

Also, you gratitously changed some of the whitespace in the file you
were modifying, which isn't a nice thing to do :)

thanks,

greg k-h
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/