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From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: Pavel Kankovsky <peak@argo.troja.mff.cuni.cz>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: Linux kernel file offset pointer races
Date: Fri, 06 Aug 2004 13:56:36 +0100	[thread overview]
Message-ID: <1091796995.16306.20.camel@localhost.localdomain> (raw)
In-Reply-To: <20040804214056.6369.0@argo.troja.mff.cuni.cz>

On Mer, 2004-08-04 at 21:36, Pavel Kankovsky wrote:
> IMHO, the proper fix is to serialize all operations modifying a shared
> file pointer (file->f_pos): read(), readv(), write(), writev(),
> lseek()/llseek(). As far as I can tell, this is required by POSIX:

Not if you want to get any useful work done. No Unix does this. The
situation with multiple parallel lseek/read/writes is somewhat undefined
anyway since you don't know if the seek or the write occurred first in
user space.

O_APPEND is a bit different, as are pread/pwrite but those are dealt
with using locking for files.



  reply	other threads:[~2004-08-06 13:59 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <Pine.LNX.4.44.0408041220550.26961-100000@isec.pl>
2004-08-04 20:36 ` Linux kernel file offset pointer races Pavel Kankovsky
2004-08-06 12:56   ` Alan Cox [this message]
2004-08-07 12:38     ` Amon Ott
2004-08-07 13:18       ` viro
2004-08-07 16:02         ` Amon Ott
2004-08-12 21:38     ` Pavel Kankovsky
2004-08-12 21:12       ` Alan Cox
2004-08-18 11:03         ` Pavel Kankovsky

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