Re: [PATCH v2] futex: mark get_robust_list as deprecated

[Cyrill Gorcunov]

On Fri, Aug 03, 2012 at 12:17:43PM +0200, richard -rw- weinberger wrote:
> On Thu, Aug 2, 2012 at 1:11 PM, Eric W. Biederman <ebiederm@xxxxxxxxxxxx> wrote:
> > richard -rw- weinberger <richard.weinberger@xxxxxxxxx> writes:
> >
> >> On Fri, Mar 23, 2012 at 8:08 PM, Kees Cook <keescook@xxxxxxxxxxxx> wrote:
> >>> Notify get_robust_list users that the syscall is going away.
> >>>
> >>> Suggested-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> >>> Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
> >>> ---
> >>
> >> I'm using this system call in an application and noticed that's marked
> >> as deprecated now.
> >> My application collects all kind of information from crashing programs.
> >> It's installed in /proc/sys/kernel/core_pattern.
> >>
> >> If program X is crashing it executes get_robust_list(X) to get the
> >> address of the robust list
> >> and reads the list from /proc/X/mem.
> >>
> >> Is there another way to get the robust list from another program (by it's pid)?
> >
> > The folks doing checkpoint/restart claim to not need this, so there
> > might be a way either that or they just haven't hit this problem yet.
> >
> > What you are doing sounds like a reasonable use of get_robust_list to me.
> >
> 
> CRIU folks, how do you deal with futex robust lists?

Well, I believe we were over-optimistic in claiming that we don't need this
syscall (to be fair I think we simply yet not faced the problem Eric points).
So we need some way to fetch this address and set it back. If get_robust_list
get deprecated maybe we could print it out in /proc/pid/stat or something?

	Cyrill
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/