Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754292AbbGXNDs (ORCPT ); Fri, 24 Jul 2015 09:03:48 -0400 Received: from smtprelay0233.hostedemail.com ([216.40.44.233]:46021 "EHLO smtprelay.hostedemail.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752721AbbGXNDp (ORCPT ); Fri, 24 Jul 2015 09:03:45 -0400 X-Session-Marker: 726F737465647440676F6F646D69732E6F7267 X-Spam-Summary: 2,0,0,,d41d8cd98f00b204,rostedt@goodmis.org,:::::::::::::::::,RULES_HIT:41:355:379:541:599:800:960:973:988:989:1260:1277:1311:1313:1314:1345:1359:1437:1515:1516:1518:1534:1540:1593:1594:1711:1730:1747:1777:1792:2393:2553:2559:2562:2918:3138:3139:3140:3141:3142:3352:3622:3865:3866:3867:3868:3871:3872:3874:4250:4321:5007:6261:7875:7903:7904:9038:10004:10400:10450:10455:10848:10967:11026:11232:11658:11914:12438:12517:12519:12663:12740:13069:13311:13357:14096:14097:19904:19999:21080,0,RBL:none,CacheIP:none,Bayesian:0.5,0.5,0.5,Netcheck:none,DomainCache:0,MSF:not bulk,SPF:fn,MSBL:0,DNSBL:none,Custom_rules:0:0:0 X-HE-Tag: glass03_35fa51074d03 X-Filterd-Recvd-Size: 2559 Date: Fri, 24 Jul 2015 09:03:42 -0400 From: Steven Rostedt To: Peter Zijlstra Cc: Linus Torvalds , Andy Lutomirski , X86 ML , "linux-kernel@vger.kernel.org" , Willy Tarreau , Borislav Petkov , Thomas Gleixner , Brian Gerst Subject: Re: Dealing with the NMI mess Message-ID: <20150724090342.6d11e16d@gandalf.local.home> In-Reply-To: <20150724124304.GH19282@twins.programming.kicks-ass.net> References: <20150723173105.6795c0dc@gandalf.local.home> <20150724081326.GO25159@twins.programming.kicks-ass.net> <20150724075841.40f209f4@gandalf.local.home> <20150724124304.GH19282@twins.programming.kicks-ass.net> X-Mailer: Claws Mail 3.11.1 (GTK+ 2.24.28; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1061 Lines: 31 On Fri, 24 Jul 2015 14:43:04 +0200 Peter Zijlstra wrote: > > I'm not too familiar with how to use hw breakpoints, but I'm guessing > > (correct me if I'm wrong) that breakpoints on code that trigger when > > executed, but watchpoints on data trigger when accessed. Then > > copy_from_user_inatomic() would only trigger on watchpoints (it's not > > executing that code, at least I hope it isn't!), and those wont bother > > us. > > These things can be: RW, W, X. > > Sure, hitting a user X watchpoint is going to be 'interesting', but its > fairly easy to hit a RW one. But do we care if we do hit one? The return from the #DB handler can use a RET. Right? -- Steve > > Just watch an on-stack variable and get perf to copy a huge chunk of > stack (like it does for the dwarf stuff). -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/