linux-kernel - Re: [RFC] Per-thread getrusage

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: <200801281354.12387.sripathik@in.ibm.com>
Date:	Mon, 28 Jan 2008 13:54:12 +0530
From:	Sripathi Kodi <sripathik@...ibm.com>
To:	Andrew Morton <akpm@...ux-foundation.org>
Cc:	Vinay Sridhar <vinay@...ux.vnet.ibm.com>,
	linux-kernel@...r.kernel.org, libc-alpha@...rceware.org,
	drepper@...hat.com, wli@...omorphy.com,
	"Eric W. Biederman" <ebiederm@...ssion.com>,
	Pavel Emelyanov <xemul@...nvz.org>
Subject: Re: [RFC] Per-thread getrusage

Hi Andrew,

On Monday 28 January 2008 11:22, Andrew Morton wrote:
> 	On Thu, 17 Jan 2008 13:57:05 +0530 Vinay Sridhar 
<vinay@...ux.vnet.ibm.com> wrote:
> > Hi All,
> >
> > Last year, there was discussion about per-thread getrusage by
> > adding RUSAGE_THREAD flag to getrusage(). Please refer to the
> > thread http://lkml.org/lkml/2007/4/4/308. Ulrich had suggested that
> > we should design a better user-space API. Specifically, we need a
> > pthread_getrusage interface in the thread library, which accepts
> > pthread_t, converts pthread_t into the corresponding tid and passes
> > it down to the syscall.
> >
> > There are two ways to implement this in the kernel:
> > 1) Introduce an additional parameter 'tid' to sys_getrusage() and
> > put code in glibc to handle getrusage() and pthread_getrusage()
> > calls correctly.
> > 2) Introduce a new system call to handle pthread_getrusage() and
> > leave sys_getrusage() untouched.
> >
> > We implemented the second idea above, simply because it avoids
> > touching any existing code. We have implemented a new syscall,
> > thread_getrusage() and we have exposed pthread_getrusage() API to
> > applications.
> >
> > Could you please share your thoughts on this? Does the approach
> > look alright? The code is hardly complete. It is just a prototype
> > that works on IA32 at the moment.
> >
> > ...
> >
> > +asmlinkage long sys_thread_getrusage(int tid, struct rusage __user
> > *ru);
>
> What happens if `tid' refers to a thread in a different pid
> namespace?

The code was only meant to be a base for discussions. It surely needs 
work. Our idea for the final version was to be able to read a thread's 
rusage from another thread strictly within the same process. The idea 
came from applications that need a cost enforcement mechanism. Having a 
mechanism for a thread to read it's own usage is essential. If there is 
a way to read other threads' rusage, it is even better.

Does Roland's patch (http://lkml.org/lkml/2008/1/18/589) look good to go 
in, provided Ulrich's comment (http://lkml.org/lkml/2008/1/19/15) is 
addressed?

Thanks,
Sripathi.
--
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/