Messages in this thread | | | From | Jessica Frazelle <> | Date | Tue, 7 Feb 2017 14:56:53 -0800 | Subject | Re: /proc/timer_list leaks the real pids of the associated processes |
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So I used to use this "feature" as a hack to see if something was running in a k8s cluster or not because fluentd gives a lot of things away. Runc basically decided to mask this file so it stopped happening though. But I think namespace aware is the right decision.
On Tue, Feb 7, 2017 at 2:48 PM Thomas Gleixner <tglx@linutronix.de> wrote: > > On Fri, 3 Feb 2017, Kees Cook wrote: > > > On Fri, Feb 3, 2017 at 2:29 PM, Xing Gao <xgao01@email.wm.edu> wrote: > > > Dear Thomas and Kees, > > > > > > I posted a bug report on bugzilla, and John asked me to send it the lkml. > > > > > > Here is the link, https://bugzilla.kernel.org/show_bug.cgi?id=193921 > > > > > > Please cc to me when you reply this email. > > > > > > And please check the information below. > > > > > > The pseudo file /proc/timer_list leaks the real pids of the associated > > > processes. > > > > > > The function print_timer(kernel/time/timer_list.c) displays > > > timer->start_pid, which is set inside the function > > > __timer_stats_timer_set_start_info (kernel/time/timer.c). This is the real > > > pid, rather than the pid in the pid namespace. If the user within a > > > container retrieves the content of /proc/timer_list, this file will leak the > > > real pid of the associated process. > > > > I feel like this has been pointed out before, but I can't find the > > email about it. Regardless, yeah, this looks true: > > > > SEQ_printf(m, ", %s/%d", tmp, timer->start_pid); > > > > #11: <0000000000000000>, hrtimer_wakeup, S:01, do_nanosleep, cron/2570 > > > > Seems like this should be made namespace aware... (and why is this > > file needed at all? Seems like it should live in debugfs not proc). > > I'm fine with that. > > The TIMER_STATS stuff should go away completely. If people are interested > in that information they can use the tracer which gives way better > data than that file. > > Thanks, > > tglx > .
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