Messages in this thread Patch in this message | | | Date | Sun, 22 Mar 2009 21:14:36 +0100 | From | Oleg Nesterov <> | Subject | Re: 2.6.28, limiting cpu time doesn't work |
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On 03/19, Peter Lojkin wrote: > > after upgrade to 2.6.28 ulimit -t doesn't work. for example: > > bash# ulimit -t 3; cpuhog > > (where cpuhog is any program that continuously use cpu) > with 2.6.27.20 cpuhog gets killed after 3sec as expected. > with 2.6.28, 2.6.28.8, 2.6.29-rc8-git4 it's keep running indefinitely. > ulimit -a and /proc/<pid>/limits show that cputime limit was set correctly.
Found this message on http://bugzilla.kernel.org/show_bug.cgi?id=12911 ...
I _think_ posix_cpu_timers_init_group() is not right, it should copy cputime_expires->prof_exp.
Peter, any chance you can test the (uncompiled/untested) patch below?
Also, I assume that something like
$ ulimit -t 3 $ while true; do true; done
kills the shell correctly, yes? IOW, I suspect that ulimit works, but cpuhog never check RLIMIT_CPU because fastpath_timer_check() always returns 0 due to task_cputime_zero(&sig->cputime_expires) == T.
I'm afraid we need the fix fo 2.6.29 as well, but I am looking at rc3.
Hmm. check_process_timers() updates ->cputime_expires, but it never clears (say) cputime_expires.prof_exp, why? Can't we just do
if (cputime_gt(sig->cputime_expires.prof_exp, prof_expires)) sig->cputime_expires.prof_exp = prof_expires; at the end?
Oleg.
--- a/kernel/fork.c +++ b/kernel/fork.c @@ -790,9 +790,7 @@ static void posix_cpu_timers_init_group( sig->it_prof_incr = cputime_zero; /* Cached expiration times. */ - sig->cputime_expires.prof_exp = cputime_zero; - sig->cputime_expires.virt_exp = cputime_zero; - sig->cputime_expires.sched_exp = 0; + sig->cputime_expires = current->signal->cputime_expires; /* The timer lists. */ INIT_LIST_HEAD(&sig->cpu_timers[0]);
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