linux-kernel - Re: How to tell whether a struct file is held by a process?

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <200905221538.09073.oliver@neukum.org>
Date:	Fri, 22 May 2009 15:38:08 +0200
From:	Oliver Neukum <oliver@...kum.org>
To:	Pantelis Koukousoulas <pktoss@...il.com>
Cc:	Kernel development list <linux-kernel@...r.kernel.org>,
	Kay Sievers <kay.sievers@...y.org>,
	Al Viro <viro@...iv.linux.org.uk>,
	Alan Stern <stern@...land.harvard.edu>
Subject: Re: How to tell whether a struct file is held by a process?

Am Freitag, 22. Mai 2009 15:30:20 schrieb Pantelis Koukousoulas:
> The only problem I find with leaving mutual exclusion 100% to userspace and
> burdening the kernel only with the decision of whether a port should be
> handled by kernel or userspace is this:
>
> Suppose a device needs a reset as part of its init sequence (a whole lot
> of them do, this is not purely hypothetical). Then a different process may
> get to operate the device before and after the reset and hilarity may
> result from that.

If you leave the locking against user space to user space this can happen
any time, not just due to a reset. What is so special about reset? You just
need a user space locking scheme operating on port numbers, not device
addresses.

	Regards
		Oliver

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