From: Sergei Shtylyov <sshtylyov@ru.mvista.com>
To: Suleiman Souhlal <ssouhlal@freebsd.org>
Cc: bzolnier@gmail.com, linux-ide@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] Correctly prevent IDE timer expiry function to run if request was already handled
Date: Fri, 06 Apr 2007 23:22:02 +0400 [thread overview]
Message-ID: <46169DDA.6020008@ru.mvista.com> (raw)
In-Reply-To: <20070406173603.GA82722@freefall.freebsd.org>
Hello.
Suleiman Souhlal wrote:
> It is possible for the timer expiry function to run even though the
> request has already been handled: ide_timer_expiry() only checks that
> the handler is not NULL, but it is possible that we have handled a
> request (thus clearing the handler) and then started a new request
> (thus starting the timer again, and setting a handler).
> A simple way to exhibit this is to set the DMA timeout to 1 jiffy and
> run dd: The kernel will panic after a few minutes because
> ide_timer_expiry() tries to add a timer when it's already active.
> To fix this, we simply add a request generation count that gets
> incremented at every interrupt, and check in ide_timer_expiry() that
> we have not already handled a new interrupt before running the expiry
> function.
Couldn't this be addressed by simply changing add_timer() to mod_timer()?
MBR, Sergei
next prev parent reply other threads:[~2007-04-06 19:22 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-04-06 17:36 [PATCH] Correctly prevent IDE timer expiry function to run if request was already handled Suleiman Souhlal
2007-04-06 19:22 ` Sergei Shtylyov [this message]
2007-04-06 20:55 ` Suleiman Souhlal
2007-04-06 21:09 ` Sergei Shtylyov
2007-04-06 21:35 ` Bartlomiej Zolnierkiewicz
2007-04-06 20:51 ` Bartlomiej Zolnierkiewicz
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