From: "Jürg Billeter" <j@bitron.ch>
To: linux-hotplug@vger.kernel.org
Subject: Re: [REPOST] uevent leak
Date: Sun, 26 Mar 2006 21:05:53 +0000 [thread overview]
Message-ID: <1143407153.4003.27.camel@juerg-pd.bitron.ch> (raw)
In-Reply-To: <442616D1.4020707@ums.usu.ru>
On Son, 2006-03-26 at 23:46 +0400, Sergey Vlasov wrote:
> On Sun, 26 Mar 2006 10:21:37 +0600 Alexander E. Patrakov wrote:
>
> > The theory (well, not theory, just an unconfirmed guess) behind this
> > bugreport, so far, is that udevd responds to uevents very quickly, faster
> > than the kernel can deliver them from the netlink socket buffer. This leads
> > to some moments when the queue is actually empty, and the loop exits
> > prematurely.
>
> Yes, the check for empty udev queue seems to be unreliable.
>
> One way to make this reliable could be to trigger some kind of "sync"
> event after all other events from udevtrigger, catch that event in an
> udev rule and do something to notify the script (e.g., remove some
> file). There is a problem, however: udevd can process events out of
> order if their DEVPATH values do not overlap (see running_with_devpath()
> in udevd.c), so the device for that event has to be really special.
Another problem is that RUN rules may trigger secondary events which
very probably get executed after that special event.
If /sys/kernel/uevent_seqnum is always up-to-date, it might be possible
to compare that file with the seqnum last processed by udev, not sure,
if this works, though.
Jürg
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prev parent reply other threads:[~2006-03-26 21:05 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-03-26 4:21 [REPOST] uevent leak Alexander E. Patrakov
2006-03-26 19:46 ` Sergey Vlasov
2006-03-26 21:05 ` Jürg Billeter [this message]
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