On 06/08, KOSAKI Motohiro wrote: > > Oleg pointed out oom_kill.c has force_sig() abuse. force_sig() mean > ignore signal mask. but SIGKILL itself is not maskable. Yes. And we have other reasons to avoid force_sig(). It should be used only for synchronous signals. But, > @@ -399,7 +399,7 @@ static int __oom_kill_process(struct task_struct *p, struct mem_cgroup *mem) > p->rt.time_slice = HZ; > set_tsk_thread_flag(p, TIF_MEMDIE); > > - force_sig(SIGKILL, p); > + send_sig(SIGKILL, p, 1); This is not right, we need send_sig(SIGKILL, p, 0). Better yet, send_sig_info(SIGKILL, SEND_SIG_NOINFO). I think send_sig() should die. The reason is that si_fromuser() must be true, otherwise we can't kill the SIGNAL_UNKILLABLE (sub-namespace inits) tasks. Oh. This reminds me, we really need the trivial (but annoying) cleanups here. The usage of SEND_SIG_ constants is messy, and they should be renamed at least. And in fact, we need the new one which acts like SEND_SIG_FORCED but si_fromuser(). We do not want to allocate the memory when the caller is oom_kill or zap_pid_ns_processes(). OK. I'll send the simple patch which adds the new helper with the comment. send_sigkill() or kernel_kill_task(), or do you see a better name? Oleg. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>