From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Sun, 20 May 2007 20:31:23 -0700 From: Andrew Morton Subject: Re: [PATCH 1/2] limit print_fatal_signal() rate (was: [RFC] log out-of-virtual-memory events) Message-Id: <20070520203123.5cde3224.akpm@linux-foundation.org> In-Reply-To: <464ED258.2010903@users.sourceforge.net> References: <464ED258.2010903@users.sourceforge.net> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: righiandr@users.sourceforge.net Cc: Bernd Eckenfels , linux-kernel@vger.kernel.org, Rik van Riel , linux-mm@kvack.org, Ingo Molnar List-ID: On Sat, 19 May 2007 12:33:04 +0200 (MEST) Andrea Righi wrote: > Bernd Eckenfels wrote: > > In article <464DCEAB.3090905@users.sourceforge.net> you wrote: > >> printk("%s/%d: potentially unexpected fatal signal %d.\n", > >> current->comm, current->pid, signr); > > > > can we have both KERN_WARNING please? > > > > Gruss > > Bernd > > Depends on print_fatal_signals patch. > > --- > > Limit the rate of print_fatal_signal() to avoid potential denial-of-service > attacks. > > Signed-off-by: Andrea Righi > > diff -urpN linux-2.6.22-rc1-mm1/kernel/signal.c linux-2.6.22-rc1-mm1-vm-log-enomem/kernel/signal.c > --- linux-2.6.22-rc1-mm1/kernel/signal.c 2007-05-19 11:25:24.000000000 +0200 > +++ linux-2.6.22-rc1-mm1-vm-log-enomem/kernel/signal.c 2007-05-19 11:30:00.000000000 +0200 > @@ -790,7 +790,10 @@ static void print_vmas(void) > > static void print_fatal_signal(struct pt_regs *regs, int signr) > { > - printk("%s/%d: potentially unexpected fatal signal %d.\n", > + if (unlikely(!printk_ratelimit())) > + return; > + > + printk(KERN_WARNING "%s/%d: potentially unexpected fatal signal %d.\n", > current->comm, current->pid, signr); > > #ifdef __i386__ Well OK. But vdso-print-fatal-signals.patch is designated not-for-mainline anyway. I think the DoS which you identify has been available for a very long time on ia64, x86_64 and perhaps others. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org