From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-oi0-f72.google.com (mail-oi0-f72.google.com [209.85.218.72]) by kanga.kvack.org (Postfix) with ESMTP id BDF616B025E for ; Mon, 17 Oct 2016 04:13:35 -0400 (EDT) Received: by mail-oi0-f72.google.com with SMTP id t73so356661191oie.5 for ; Mon, 17 Oct 2016 01:13:35 -0700 (PDT) Received: from EUR03-DB5-obe.outbound.protection.outlook.com (mail-eopbgr40123.outbound.protection.outlook.com. [40.107.4.123]) by mx.google.com with ESMTPS id g68si10808242otb.98.2016.10.17.01.13.34 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Mon, 17 Oct 2016 01:13:34 -0700 (PDT) Subject: Re: [PATCH] kasan: support panic_on_warn References: <1476465002-2728-1-git-send-email-dvyukov@google.com> From: Andrey Ryabinin Message-ID: <2b39f90e-2c67-fafb-dc48-f642c62bead6@virtuozzo.com> Date: Mon, 17 Oct 2016 11:13:42 +0300 MIME-Version: 1.0 In-Reply-To: <1476465002-2728-1-git-send-email-dvyukov@google.com> Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Dmitry Vyukov , akpm@linux-foundation.org, glider@google.com Cc: kasan-dev@googlegroups.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org On 10/14/2016 08:10 PM, Dmitry Vyukov wrote: > If user sets panic_on_warn, he wants kernel to panic if there is > anything barely wrong with the kernel. KASAN-detected errors > are definitely not less benign than an arbitrary kernel WARNING. > > Panic after KASAN errors if panic_on_warn is set. > > We use this for continuous fuzzing where we want kernel to stop > and reboot on any error. > > Signed-off-by: Dmitry Vyukov > Cc: kasan-dev@googlegroups.com > Cc: Andrey Ryabinin > Cc: Alexander Potapenko > Cc: Andrew Morton > Cc: linux-mm@kvack.org > Cc: linux-kernel@vger.kernel.org > --- > mm/kasan/report.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/mm/kasan/report.c b/mm/kasan/report.c > index 24c1211..ca0bd48 100644 > --- a/mm/kasan/report.c > +++ b/mm/kasan/report.c > @@ -133,6 +133,10 @@ static void kasan_end_report(unsigned long *flags) > pr_err("==================================================================\n"); > add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE); > spin_unlock_irqrestore(&report_lock, *flags); > + if (panic_on_warn) { > + panic_on_warn = 0; Why we need to reset panic_on_warn? I assume this was copied from __warn(). AFAIU in __warn() this protects from recursion: __warn() -> painc() ->__warn() -> panic() -> ... which is possible if WARN_ON() triggered in panic(). But KASAN is protected from such recursion via kasan_disable_current(). > + panic("panic_on_warn set ...\n"); > + } > kasan_enable_current(); > } > > -- 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