From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753382AbcHBKWr (ORCPT ); Tue, 2 Aug 2016 06:22:47 -0400 Received: from mail-db5eur01on0107.outbound.protection.outlook.com ([104.47.2.107]:23440 "EHLO EUR01-DB5-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752121AbcHBKWj (ORCPT ); Tue, 2 Aug 2016 06:22:39 -0400 Authentication-Results: spf=none (sender IP is ) smtp.mailfrom=aryabinin@virtuozzo.com; Subject: Re: [PATCH] kasan: avoid overflowing quarantine size on low memory systems To: Alexander Potapenko , Dmitry Vyukov References: <1470063563-96266-1-git-send-email-glider@google.com> <57A06F23.9080804@virtuozzo.com> CC: Kostya Serebryany , Andrey Konovalov , Christoph Lameter , Andrew Morton , Steven Rostedt , Joonsoo Kim , Joonsoo Kim , Kuthonuzo Luruo , kasan-dev , LKML , "linux-mm@kvack.org" From: Andrey Ryabinin Message-ID: <57A074AF.3040505@virtuozzo.com> Date: Tue, 2 Aug 2016 13:23:43 +0300 User-Agent: Mozilla/5.0 (X11; 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I'd suggest pr_warn_once(); >> >> >> I would suggest to just do something useful. Setting quarantine >> new_quarantine_size to 0 looks fine. >> What would user do with this warning? Number of CPUs and amount of >> memory are generally fixed. Why is it an issue for end user at all? We >> still have some quarantine per-cpu. A WARNING means a [non-critical] >> kernel bug. E.g. syzkaller will catch each and every boot of such >> system as a bug. > How about printk_once then? > Silently setting the quarantine size to zero may puzzle the user. > Nope, user will not notice anything. So keeping it silent would be better. Plus it's very unlikely that this will ever happen in real life.