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]

Date:	Fri, 22 May 2009 16:52:23 +0300
From:	Pantelis Koukousoulas <pktoss@...il.com>
To:	Alan Cox <alan@...rguk.ukuu.org.uk>
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?

On Fri, May 22, 2009 at 4:43 PM, Alan Cox <alan@...rguk.ukuu.org.uk> wrote:
>> 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.
>
> Thats surely up to you to get your lock file usage right. The kernel
> isn't there to play mother to crap programming.

Who is "me" in this case? Assuming that those writing the userspace programs
are cooperative though, I agree. We can declare that whatever program does not
play by the (userspace locking) rules is crap and either fix it (if open source)
or refuse to install it / complain (if closed source).

>
>> So, if there is a clean / acceptable way to handle the reset issue in userspace
>
> Firstly can you explain *why* you think there is a problem ?
>

I admit this could be a bias from the way I imagined the whole thing
to work before
this discussion. I think I can see how a userspace locking scheme based on port
numbers could avoid also the reset problem.

Thanks,
Pantelis
--
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/