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posix-timers: fix RLIMIT_CPU && fork()

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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.

Reported-by: Peter Lojkin <ia6432@inbox.ru>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Peter Lojkin <ia6432@inbox.ru>
Cc: Roland McGrath <roland@redhat.com>
Cc: stable@kernel.org
LKML-Reference: <20090327000607.GA10104@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Oleg Nesterov 2009-03-27 01:06:07 +01:00 committed by Ingo Molnar
parent 633fe795b8
commit 6279a751fe
1 changed files with 9 additions and 4 deletions
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13
kernel/fork.c
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@ -808,6 +808,12 @@ static void posix_cpu_timers_init_group(struct signal_struct *sig)
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 clone_flags, struct task_struct *tsk)
atomic_inc(&current->signal->live);
return 0;
}
sig = kmem_cache_alloc(signal_cachep, GFP_KERNEL);
if (sig)
posix_cpu_timers_init_group(sig);
tsk->signal = sig;
if (!sig)
return -ENOMEM;
@ -865,6 +868,8 @@ static int copy_signal(unsigned long clone_flags, struct task_struct *tsk)
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);