Date: Sun, 24 Aug 2008 06:00:10 +0000 From: "Poul-Henning Kamp" <phk@phk.freebsd.dk> To: "M. Warner Losh" <imp@bsdimp.com> Cc: freebsd-usb@freebsd.org Subject: Re: usb4bsd patch review Message-ID: <13745.1219557610@critter.freebsd.dk> In-Reply-To: Your message of "Sat, 23 Aug 2008 22:39:51 CST." <20080823.223951.-962047221.imp@bsdimp.com>
next in thread | previous in thread | raw e-mail | index | archive | help
In message <20080823.223951.-962047221.imp@bsdimp.com>, "M. Warner Losh" writes : >In message: <10826.1219511738@critter.freebsd.dk> > "Poul-Henning Kamp" <phk@phk.freebsd.dk> writes: >: In message <20080823.100155.1310242209.imp@bsdimp.com>, "M. Warner Losh" writes >: : >: >: >While this may be a good idea, I'm hesitant about races that it may >: >introduce. This is the classic point of attack: do something between >: >steps of a formerly atomic operation that was made non-atomic. I >: >can't think of anything off the top of my head, but I'm still >: >concerned. >: >: We have ways of closing the race if need be, but they're all slightly >: kludgy, but I am not overly concerned about those races as long as >: the default is to not give access. > >I guess I'm worried about a device that comes and goes and comes back >and there being some difference between the two that causes us to >bogusly do something to the new device that was appropriate for the >old one, but not the new one... That scenario is always present as far as I can tell... -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk@FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence.
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?13745.1219557610>