posix-timers: fix RLIMIT_CPU && fork() (6279a751) · Commits · 戴 / test

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>

kernel/fork.c

+9 −4

Original line number	Diff line number	Diff line
		@@ -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);

		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 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);

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