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Re: tx_timeout and timer serialisation

To: kuznet@xxxxxxxxxxxxx
Subject: Re: tx_timeout and timer serialisation
From: Andrew Morton <andrewm@xxxxxxxxxx>
Date: Thu, 11 May 2000 02:24:54 +0000
Cc: netdev@xxxxxxxxxxx
References: <390EE5BB.2AF2F1CD@xxxxxxxxxx> from "Andrew Morton" at May 3, 0 00:27:07 am <200005021549.TAA16319@xxxxxxxxxxxxx>
Sender: owner-netdev@xxxxxxxxxxx
kuznet@xxxxxxxxxxxxx wrote:
> 
> Hello!

Hello indeed.  I'm catching up on a week away...

[ Regarding del_timer_sync() ]

> Alas, it has fatal bug. Namely, timer handler _code_ can be released
> in between timer_exit() and return from handler. It is utterly
> unlikely, but the bug is fatal. 8) I do not know how to repair
> this without refcounts.

Why does the handler have to call timer_exit() at all?

Could we not clear timer->running in run_timer_list()?  That would
certainly protect us from the problem you identify...

-- 
-akpm-

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