From: James Simmons <jsimmons@edgeglobal.com>
To: "Stephen C. Tweedie" <sct@redhat.com>
Cc: Linux MM <linux-mm@kvack.org>
Subject: Re: MMIO regions
Date: Mon, 4 Oct 1999 14:29:14 -0400 (EDT) [thread overview]
Message-ID: <Pine.LNX.4.10.9910041428030.8295-100000@imperial.edgeglobal.com> (raw)
In-Reply-To: <14328.53659.36975.874284@dukat.scot.redhat.com>
On Mon, 4 Oct 1999, Stephen C. Tweedie wrote:
> Hi,
>
> On Mon, 4 Oct 1999 11:52:50 -0400 (EDT), James Simmons
> <jsimmons@edgeglobal.com> said:
>
> >> The kernel doesn't impose any limits against this. If you want to make
> >> this impossible, then you need to add locking to the driver itself to
> >> prevent multiple processes from conflicting.
>
> > And if the process holding the locks dies then no other process can access
> > this resource. Also if the program forgets to release the lock you end up
> > with other process never being able to access this piece of hardware.
>
> There are any number of ways to recover from this. SysV semaphores, for
> example, allow you to specify UNDO when you down a semaphore, and the
> semaphore will be restored automatically on process death.
>
> --Stephen
>
Okay. But none of this prevents a rogue app from hosing your system. Such
a process doesn't have to bother with locks or semaphores.
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next prev parent reply other threads:[~1999-10-04 18:29 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
1999-10-04 14:38 James Simmons
1999-10-04 15:31 ` Stephen C. Tweedie
1999-10-04 15:52 ` James Simmons
1999-10-04 16:02 ` Benjamin C.R. LaHaise
1999-10-04 17:27 ` James Simmons
1999-10-04 17:56 ` Benjamin C.R. LaHaise
1999-10-04 18:26 ` James Simmons
1999-10-04 19:19 ` Stephen C. Tweedie
1999-10-06 20:15 ` James Simmons
1999-10-11 17:09 ` Stephen C. Tweedie
1999-10-11 17:26 ` Jeff Garzik
1999-10-11 23:14 ` James Simmons
1999-10-11 17:57 ` James Simmons
1999-10-04 16:11 ` Stephen C. Tweedie
1999-10-04 18:29 ` James Simmons [this message]
1999-10-04 19:35 ` Stephen C. Tweedie
1999-10-07 19:40 ` James Simmons
1999-10-10 11:24 ` Rik Faith
1999-10-10 14:03 ` Eric W. Biederman
1999-10-10 18:46 ` Rik Faith
1999-10-11 0:21 ` James Simmons
1999-10-11 10:59 ` Rik Faith
1999-10-11 3:38 ` Eric W. Biederman
1999-10-10 14:21 ` James Simmons
1999-10-11 17:22 ` Stephen C. Tweedie
1999-10-04 16:58 ` Marcus Sundberg
1999-10-04 18:27 ` James Simmons
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