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    SubjectRe: [PATCH 1/2] posix-timers: fix RLIMIT_CPU && fork()
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    On Fri, 2009-03-27 at 01:06 +0100, Oleg Nesterov wrote:
    > See http://bugzilla.kernel.org/show_bug.cgi?id=12911
    >
    > copy_signal() copies signal->rlim, but RLIMIT_CPU is "lost". Because
    > posix_cpu_timers_init_group() sets cputime_expires.prof_exp = 0 and thus
    > fastpath_timer_check() returns false unless we have other expired cpu timers.
    >
    > Change copy_signal() to set cputime_expires.prof_exp if we have RLIMIT_CPU.
    > Also, set cputimer.running = 1 in that case. This is not strictly necessary,
    > but imho makes sense.

    The other site that enables is also syncs the timer with the clock, but
    since we're doing clone_signal, I presume there isn't much of a thread
    group to sync to anyway.

    Looks good, thanks for looking into this.

    Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>

    > Reported-by: Peter Lojkin <ia6432@inbox.ru>
    > Signed-off-by: Oleg Nesterov <oleg@redhat.com>
    >
    > --- 6.29/kernel/fork.c~1_FORK 2009-03-23 18:14:34.000000000 +0100
    > +++ 6.29/kernel/fork.c 2009-03-27 00:25:52.000000000 +0100
    > @@ -808,6 +808,12 @@ static void posix_cpu_timers_init_group(
    > sig->cputime_expires.virt_exp = cputime_zero;
    > sig->cputime_expires.sched_exp = 0;
    >
    > + if (sig->rlim[RLIMIT_CPU].rlim_cur != RLIM_INFINITY) {
    > + sig->cputime_expires.prof_exp =
    > + secs_to_cputime(sig->rlim[RLIMIT_CPU].rlim_cur);
    > + sig->cputimer.running = 1;
    > + }
    > +
    > /* The timer lists. */
    > INIT_LIST_HEAD(&sig->cpu_timers[0]);
    > INIT_LIST_HEAD(&sig->cpu_timers[1]);
    > @@ -823,11 +829,8 @@ static int copy_signal(unsigned long clo
    > atomic_inc(&current->signal->live);
    > return 0;
    > }
    > - sig = kmem_cache_alloc(signal_cachep, GFP_KERNEL);
    > -
    > - if (sig)
    > - posix_cpu_timers_init_group(sig);
    >
    > + sig = kmem_cache_alloc(signal_cachep, GFP_KERNEL);
    > tsk->signal = sig;
    > if (!sig)
    > return -ENOMEM;
    > @@ -865,6 +868,8 @@ static int copy_signal(unsigned long clo
    > memcpy(sig->rlim, current->signal->rlim, sizeof sig->rlim);
    > task_unlock(current->group_leader);
    >
    > + posix_cpu_timers_init_group(sig);
    > +
    > acct_init_pacct(&sig->pacct);
    >
    > tty_audit_fork(sig);
    >



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