From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756144AbZKKBNG (ORCPT ); Tue, 10 Nov 2009 20:13:06 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755594AbZKKBNF (ORCPT ); Tue, 10 Nov 2009 20:13:05 -0500 Received: from gate.crashing.org ([63.228.1.57]:58507 "EHLO gate.crashing.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755473AbZKKBNE (ORCPT ); Tue, 10 Nov 2009 20:13:04 -0500 Subject: Re: [PATCH] powerpc: _exception: kill the obsolete code under is_global_init() From: Benjamin Herrenschmidt To: Oleg Nesterov Cc: Andrew Morton , Geert Uytterhoeven , Kumar Gala , Liu Yu , Roland McGrath , linux-kernel@vger.kernel.org In-Reply-To: <20091110002542.GA1312@redhat.com> References: <20091110002542.GA1312@redhat.com> Content-Type: text/plain; charset="UTF-8" Date: Wed, 11 Nov 2009 12:12:54 +1100 Message-ID: <1257901974.2140.11.camel@pasglop> Mime-Version: 1.0 X-Mailer: Evolution 2.28.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2009-11-10 at 01:25 +0100, Oleg Nesterov wrote: > The code under "if (is_global_init())" is bogus, and is_global_init() > itself is not right in mt case. > > Contrary to what the comment says, nowadays force_sig_info() does kill > init even if the handler is SIG_DFL. Note that force_sig_info() clears > SIGNAL_UNKILLABLE exactly for this case. > > Signed-off-by: Oleg Nesterov > --- Thanks. I'll take that one. Cheers, Ben. > arch/powerpc/kernel/traps.c | 22 ---------------------- > 1 file changed, 22 deletions(-) > > --- TH/arch/powerpc/kernel/traps.c~PPC_EXCEPTION_DONT_CK_INIT 2009-11-10 01:03:23.000000000 +0100 > +++ TH/arch/powerpc/kernel/traps.c 2009-11-10 01:06:41.000000000 +0100 > @@ -198,28 +198,6 @@ void _exception(int signr, struct pt_reg > info.si_code = code; > info.si_addr = (void __user *) addr; > force_sig_info(signr, &info, current); > - > - /* > - * Init gets no signals that it doesn't have a handler for. > - * That's all very well, but if it has caused a synchronous > - * exception and we ignore the resulting signal, it will just > - * generate the same exception over and over again and we get > - * nowhere. Better to kill it and let the kernel panic. > - */ > - if (is_global_init(current)) { > - __sighandler_t handler; > - > - spin_lock_irq(¤t->sighand->siglock); > - handler = current->sighand->action[signr-1].sa.sa_handler; > - spin_unlock_irq(¤t->sighand->siglock); > - if (handler == SIG_DFL) { > - /* init has generated a synchronous exception > - and it doesn't have a handler for the signal */ > - printk(KERN_CRIT "init has generated signal %d " > - "but has no handler for it\n", signr); > - do_exit(signr); > - } > - } > } > > #ifdef CONFIG_PPC64