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=-10.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,MAILING_LIST_MULTI,SPF_HELO_NONE,URIBL_BLOCKED autolearn=unavailable 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 032BAC48BE6 for ; Wed, 16 Jun 2021 22:13:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D181E61076 for ; Wed, 16 Jun 2021 22:13:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234194AbhFPWPt (ORCPT ); Wed, 16 Jun 2021 18:15:49 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:31626 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232258AbhFPWPo (ORCPT ); Wed, 16 Jun 2021 18:15:44 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1623881616; 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=ynFypKw6yaFTAwjszi5wGpSPgyHOdH7h2sszX4y3jj8=; b=IfXqqk5qaqrzRdlu5QqLvnvN/WViw6bq5BA+bUw0RjzLsxXPdoDKmN3jac/G/WbcEw7KHd fXuR7NVoEDsoHjmfEbPtLUr5p0u688UzX1aVFwuvlmf8bIcUGPOPqI/Swt+0lCdPfBWVva 9izL68n31TlNiBTocmkhXcyPeu5huNA= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-231-sP0V_TQWNIyTTK4aNmmkdg-1; Wed, 16 Jun 2021 18:13:33 -0400 X-MC-Unique: sP0V_TQWNIyTTK4aNmmkdg-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 867BA1084F41; Wed, 16 Jun 2021 22:13:31 +0000 (UTC) Received: from optiplex-fbsd (unknown [10.3.128.11]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 1BB4710016F4; Wed, 16 Jun 2021 22:13:28 +0000 (UTC) Date: Wed, 16 Jun 2021 18:13:26 -0400 From: Rafael Aquini To: Vlastimil Babka Cc: Georgi Djakov , akpm@linux-foundation.org, iamjoonsoo.kim@lge.com, rientjes@google.com, penberg@kernel.org, cl@linux.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, djakov@kernel.org Subject: Re: [PATCH] mm/slub: Add taint after the errors are printed Message-ID: References: <1623860738-146761-1-git-send-email-quic_c_gdjako@quicinc.com> <4b22baf7-582b-f1ae-a525-046a493ec85f@suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4b22baf7-582b-f1ae-a525-046a493ec85f@suse.cz> X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jun 16, 2021 at 06:34:41PM +0200, Vlastimil Babka wrote: > On 6/16/21 6:25 PM, Georgi Djakov wrote: > > When running the kernel with panic_on_taint, the usual slub debug error > > messages are not being printed when object corruption happens. That's > > because we panic in add_taint(), which is called before printing the > > additional information. This is a bit unfortunate as the error messages > > are actually very useful, especially before a panic. Let's fix this by > > moving add_taint() after the errors are printed on the console. > > > > Signed-off-by: Georgi Djakov > > Makes sense. > > While at it, I wonder if we should use LOCKDEP_STILL_OK instead of > LOCKDEP_NOW_UNRELIABLE. Isn't it too pessimistic to assume that some slab's > memory corruption hit some lock state? > Given there is noted corruption I don't think it's safe to assume otherwise.