Date: Wed, 29 Feb 2012 09:36:02 -0500 From: John Baldwin <jhb@freebsd.org> To: Konstantin Belousov <kostikbel@gmail.com> Cc: src-committers@freebsd.org, Pawel Jakub Dawidek <pjd@freebsd.org>, svn-src-all@freebsd.org, Mikolaj Golub <trociny@freebsd.org>, "Robert N. M. Watson" <rwatson@freebsd.org>, svn-src-head@freebsd.org, Julian Elischer <julian@freebsd.org> Subject: Re: svn commit: r232181 - in head/sys: kern sys Message-ID: <201202290936.02309.jhb@freebsd.org> In-Reply-To: <20120229132507.GB55074@deviant.kiev.zoral.com.ua> References: <201202261425.q1QEPm9g069102@svn.freebsd.org> <86mx81byt6.fsf@in138.ua3> <20120229132507.GB55074@deviant.kiev.zoral.com.ua>
next in thread | previous in thread | raw e-mail | index | archive | help
On Wednesday, February 29, 2012 8:25:07 am Konstantin Belousov wrote: > On Wed, Feb 29, 2012 at 02:37:25PM +0200, Mikolaj Golub wrote: > > > > On Wed, 29 Feb 2012 12:03:00 +0000 Robert N. M. Watson wrote: > > > > RNMW> I think the monitoring aspect of the patch is fine. > > > > RNMW> The bit I was worried about was external umask changes. This can cause > > RNMW> race conditions for applications that manage their umask -- for > > RNMW> example, bsdtar, if I recall correctly. It's one thing to use a > > RNMW> debugger to force an application to change its umask -- the developer > > RNMW> needs to know they are changing application behaviour. But exposing a > > RNMW> feature that can lead to correct applications but incorrect results is > > RNMW> a risky thing to do, hence my objection. > > > > RNMW> I think given the other objections, it would be wise to remove write > > RNMW> access to process umasks, but retain read access for procstat (which is > > RNMW> quite useful, I agree). > > > > I still don't see why having a sysctl RW is worse than asking users to run > > something like in the attach when they need to change umask for another > > process, but ok, if people don't like RW I will remove it. > > > What is done is attach is much worse then the sysctl, just because > debugger attach often causes spurious EINTR, indeed seriously disrupting > applications, as opposed to some uncertain damage that could be done in > theory. kgdb doesn't though, and presumably for umask you would change it via kgdb, so from the running process' perspective it would look the same as changing it via sysctl. -- John Baldwin
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?201202290936.02309.jhb>