From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 57DF7C6377B for ; Wed, 21 Jul 2021 20:36:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3D01761003 for ; Wed, 21 Jul 2021 20:36:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232446AbhGUTze (ORCPT ); Wed, 21 Jul 2021 15:55:34 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56134 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229803AbhGUTzd (ORCPT ); Wed, 21 Jul 2021 15:55:33 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C1DF4C061575 for ; Wed, 21 Jul 2021 13:36:09 -0700 (PDT) From: Thomas Gleixner DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1626899767; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=VhovpCDMe6qYvpY3LIzNmgTjkTz8Q04ycc21UN9oufA=; b=UK2zeV1RXy7ul4dkcmxFImbE+m20gPvafLWpJWzJAa3oXMdMVmeebh4GCvJ78W4BYf0tjk zUzEZFtJ6/QxSCe54orsYwW4i3DaIVeq/wkBMoO802pvXH0iKj22d7DB1ArfRGZce/xve4 TcM3uFqtlNW5vcz+Sv6jTqQvvr5NAB+XKlILVK45Cqas9lahn95Huo2uBx/YpIyrZdcOw6 npeGcYZxaR2z7Q9MgI66+cP1IRJIY4vyQ6RNMWSqfUyz01XVUbDDV2W/7FwXypedHZmu1F s3wLinTjvHdaymPek8hBjdceSkV+Ajvnxw8m7kJcnaLPprRfKVsRvGl32XKbTQ== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1626899767; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=VhovpCDMe6qYvpY3LIzNmgTjkTz8Q04ycc21UN9oufA=; b=Q35vB6KKP75fXv/myH8LmcYww7OrbBTlhpEwSNfivsguyeXXnjE3o+He2KvQ5eLfvMsIlB n0JxhQgFkY8mPdDQ== To: Rik van Riel , linux-kernel@vger.kernel.org Cc: Dave Hansen , Andy Lutomirski , kernel-team@fb.com, Peter Zijlstra , Ingo Molnar , Borislav Petkov , x86@kernel.org Subject: Re: [PATCH] x86,mm: print likely CPU at segfault time In-Reply-To: <20210719150041.3c719c94@imladris.surriel.com> References: <20210719150041.3c719c94@imladris.surriel.com> Date: Wed, 21 Jul 2021 22:36:07 +0200 Message-ID: <87sg07pfpk.ffs@nanos.tec.linutronix.de> MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Rik, On Mon, Jul 19 2021 at 15:00, Rik van Riel wrote: > > Adding a printk to show_signal_msg() achieves that purpose. It isn't > perfect since the task might get rescheduled on another CPU between > when the fault hit and when the message is printed, but it should be > good enough to show correlation between userspace and kernel errors > when dealing with a bad CPU. we could collect the cpu number in do_*_addr_fault() before interrupts are enabled and just hand it through. There are only a few callchains which end up in __bad_area_nosemaphore(). Thanks, tglx