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=-2.3 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT autolearn=ham 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 E4923C04A6B for ; Fri, 10 May 2019 05:07:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B2BF62177B for ; Fri, 10 May 2019 05:07:16 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="c0UMDkfB" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727001AbfEJFHP (ORCPT ); Fri, 10 May 2019 01:07:15 -0400 Received: from mail-pl1-f195.google.com ([209.85.214.195]:45334 "EHLO mail-pl1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726587AbfEJFHO (ORCPT ); Fri, 10 May 2019 01:07:14 -0400 Received: by mail-pl1-f195.google.com with SMTP id a5so2226545pls.12; Thu, 09 May 2019 22:07:14 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=FjMDX6OXptCPbOEPZorERjXrFHT+sQLeZXg4fcoOVO4=; b=c0UMDkfB6tTjOuuL7w77f9bWKLRAazsReBhnmqpNGDM0k59e6X/kl3C4Pe6J9eHUen VFAkbAqGjUIJBx7hvW7Fh6dqtrYSHH9XX2PvuEVj32Jy9VNtfv95QPZNAgVJgPRL3BKO OyB6K6sIcnJOt80RK+9Kgdu4JyMQCO4sdI1JvFP7WzWDVWm7oHYsqPIL5NCA8RM1tJ12 ggKw4hwLADwL4j8sXY2gT6/wneNWSju7qCVIsYvNXQPH+QrW25KdR1AYG7U4Rz8in6rI qNWUTknwUpjjpgfRE8r4QpfQla/BLjPtT0IOYTbpCwB99LwTtNvLRfDE7OPzwXu3cz1B Lx1w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=FjMDX6OXptCPbOEPZorERjXrFHT+sQLeZXg4fcoOVO4=; b=qP0NRHx+jxEvRyzVqhIgI8yrfGIw9S+AyBlNh6wYpKYOvQAkGiCRNOWtPUIEvl9Yz3 pDPrg5z4P6992n747ySDUd7zKsScagwK1PLzctMf6g0LUoJM0y/ehmrCa67P3IbSDspq p0X+fDRdju5GguLGKLJ0Y+I0IkHpWqSu5e6+rsHeQx5xyVfEbRyJw6Y9ersmj50DBkA+ qTgyWJVlP0Y+AZj+yWUKCATyO9xvtdl/vLyfOdRua+1efSLtRrVOOZuN0dY5criaXAg5 zHgdB4+fbG22Hbd9dSUxW9Li6zeyasWejB80NjnhBQ9eWouTemxtLZ/yYKo4zAgi+i+S x78g== X-Gm-Message-State: APjAAAVRjkQ4g/n489TF531osDJFiVkMdMixsQCctb6etXmiNbU8gqvf ZPtNBWsQYjT3PuuDvLZkw0g= X-Google-Smtp-Source: APXvYqzNL5x5L+kA/IjbOlsUuaCt+dnLaiieinMh/bSrZ4GSD+ciNLFNHlYGUDHIszX5LplSP6e0cA== X-Received: by 2002:a17:902:8c85:: with SMTP id t5mr10664151plo.23.1557464834204; Thu, 09 May 2019 22:07:14 -0700 (PDT) Received: from localhost ([39.7.15.25]) by smtp.gmail.com with ESMTPSA id d67sm5741186pfa.35.2019.05.09.22.07.12 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Thu, 09 May 2019 22:07:13 -0700 (PDT) Date: Fri, 10 May 2019 14:07:09 +0900 From: Sergey Senozhatsky To: Linus Torvalds Cc: Sergey Senozhatsky , Petr Mladek , Andy Shevchenko , Rasmus Villemoes , "Tobin C . Harding" , Michal Hocko , Sergey Senozhatsky , Steven Rostedt , linux-kernel@vger.kernel.org, Michael Ellerman , linuxppc-dev@lists.ozlabs.org, Russell Currey , Christophe Leroy , Stephen Rothwell , Heiko Carstens , linux-arch@vger.kernel.org, linux-s390@vger.kernel.org, Martin Schwidefsky Subject: Re: [PATCH] vsprintf: Do not break early boot with probing addresses Message-ID: <20190510050709.GA1831@jagdpanzerIV> References: <20190509121923.8339-1-pmladek@suse.com> <20190510043200.GC15652@jagdpanzerIV> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.11.4 (2019-03-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On (05/09/19 21:47), Linus Torvalds wrote: > [ Sorry about html and mobile crud, I'm not at the computer right now ] > How about we just undo the whole misguided probe_kernel_address() thing? But the problem will remain - %pS/%pF on PPC (and some other arch-s) do dereference_function_descriptor(), which calls probe_kernel_address(). So if probe_kernel_address() starts to dump_stack(), then we are heading towards stack overflow. Unless I'm totally missing something. -ss 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=-2.0 required=3.0 tests=DKIM_ADSP_CUSTOM_MED, DKIM_INVALID,DKIM_SIGNED,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT 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 0E47EC04A6B for ; Fri, 10 May 2019 05:08:40 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 4C9D82177B for ; Fri, 10 May 2019 05:08:39 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="c0UMDkfB" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4C9D82177B Authentication-Results: mail.kernel.org; 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Thu, 09 May 2019 22:07:14 -0700 (PDT) Received: from localhost ([39.7.15.25]) by smtp.gmail.com with ESMTPSA id d67sm5741186pfa.35.2019.05.09.22.07.12 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Thu, 09 May 2019 22:07:13 -0700 (PDT) Date: Fri, 10 May 2019 14:07:09 +0900 From: Sergey Senozhatsky To: Linus Torvalds Subject: Re: [PATCH] vsprintf: Do not break early boot with probing addresses Message-ID: <20190510050709.GA1831@jagdpanzerIV> References: <20190509121923.8339-1-pmladek@suse.com> <20190510043200.GC15652@jagdpanzerIV> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.11.4 (2019-03-13) X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Petr Mladek , linux-arch@vger.kernel.org, Sergey Senozhatsky , Heiko Carstens , linux-s390@vger.kernel.org, Rasmus Villemoes , linux-kernel@vger.kernel.org, Steven Rostedt , Michal Hocko , Sergey Senozhatsky , Stephen Rothwell , Andy Shevchenko , linuxppc-dev@lists.ozlabs.org, Martin Schwidefsky , "Tobin C . Harding" Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On (05/09/19 21:47), Linus Torvalds wrote: > [ Sorry about html and mobile crud, I'm not at the computer right now ] > How about we just undo the whole misguided probe_kernel_address() thing? But the problem will remain - %pS/%pF on PPC (and some other arch-s) do dereference_function_descriptor(), which calls probe_kernel_address(). So if probe_kernel_address() starts to dump_stack(), then we are heading towards stack overflow. Unless I'm totally missing something. -ss