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=-11.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 A4E56C433E5 for ; Sun, 21 Mar 2021 05:34:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 725B361952 for ; Sun, 21 Mar 2021 05:34:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230031AbhCUF0s (ORCPT ); Sun, 21 Mar 2021 01:26:48 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46716 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229791AbhCUF0T (ORCPT ); Sun, 21 Mar 2021 01:26:19 -0400 Received: from mail-pf1-x429.google.com (mail-pf1-x429.google.com [IPv6:2607:f8b0:4864:20::429]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A448AC061574 for ; Sat, 20 Mar 2021 22:26:18 -0700 (PDT) Received: by mail-pf1-x429.google.com with SMTP id y5so8732064pfn.1 for ; Sat, 20 Mar 2021 22:26:18 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=Hh7shEFqN+4YQy0DWvjoXzsDlDCaLtw9ra44KHPWHkg=; b=CjBgjxTr+npHKRoZHWRNroG1zVN7+AkzcS/lmkSLNlF4EKxZnVNJjDShIuxxxAbDMP Zi7BM7SPsQiwW3sjUNxe7wSxx8345a5fj0NJPVkLBGCQUl1vmxZJ8jBKoC1wCrRzdvKX XajNGZiZipEMON2F1c0CexM5NZ+JccY+8RIow= 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; bh=Hh7shEFqN+4YQy0DWvjoXzsDlDCaLtw9ra44KHPWHkg=; b=h+9IFGxGTNiE6pzE7+pIUmDOzJ2NBIpxIuxftjsqKutDEeppIiNiS9vrBZ4p6ssanK hVwD/GU+40DcTpidl8T1AWWQqrtdoRB0SOzbl1bS3WRbrH+7hiQ92xyfFQVGQazV2Mr6 qRkdWmTWBLjBwR5INEoGtPnAlryD97anO208wcdv/lS2EuqeC4rnxBk2/jbGwb5jvQcJ t+EecUIOlFrGv7t0688WGaqt95P88Gc7xQV9oDrcF1JF8DILVfXi7i7ydJpTZ8/Wjbmm d9N42s/xpFsmu/rm+KRE2jIzNMVmVMGpUrkFGjRfJOoeHaSnYvoEDoD/VWV9VyNcKlU7 N1nA== X-Gm-Message-State: AOAM533S90t4/DATP/4MYbUphK43KnXbg5vGBjA3wYxlq2DD4eetT3AG r9cWdsj5BlSmCNXRPdUClqGEsQ== X-Google-Smtp-Source: ABdhPJzWtY3HUJYpBDSoqpysrTRhl3hfq3Gue+pAzMn1TblrjdoVsbczMaY8+SWExQl6c3ccUGZpXA== X-Received: by 2002:a63:1845:: with SMTP id 5mr18028063pgy.244.1616304378263; Sat, 20 Mar 2021 22:26:18 -0700 (PDT) Received: from google.com ([2409:10:2e40:5100:2dfa:a0a:77ff:3953]) by smtp.gmail.com with ESMTPSA id x190sm9815525pfx.60.2021.03.20.22.26.12 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 20 Mar 2021 22:26:17 -0700 (PDT) Date: Sun, 21 Mar 2021 14:26:10 +0900 From: Sergey Senozhatsky To: John Ogness Cc: Petr Mladek , Steven Rostedt , Thomas Gleixner , linux-kernel@vger.kernel.org, Michael Ellerman , Benjamin Herrenschmidt , Paul Mackerras , Eric Biederman , Nicholas Piggin , Christophe Leroy , Alistair Popple , Jordan Niethe , Peter Zijlstra , =?iso-8859-1?Q?C=E9dric?= Le Goater , Andrew Morton , Kees Cook , Yue Hu , Alexey Kardashevskiy , Rafael Aquini , Tiezhu Yang , "Guilherme G. Piccoli" , "Paul E. McKenney" , linuxppc-dev@lists.ozlabs.org, kexec@lists.infradead.org Subject: Re: [PATCH next v1 2/3] printk: remove safe buffers Message-ID: References: <20210316233326.10778-1-john.ogness@linutronix.de> <20210316233326.10778-3-john.ogness@linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210316233326.10778-3-john.ogness@linutronix.de> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On (21/03/17 00:33), John Ogness wrote: [..] > void printk_nmi_direct_enter(void) > { > @@ -324,27 +44,8 @@ void printk_nmi_direct_exit(void) > this_cpu_and(printk_context, ~PRINTK_NMI_DIRECT_CONTEXT_MASK); > } > > -#else > - > -static __printf(1, 0) int vprintk_nmi(const char *fmt, va_list args) > -{ > - return 0; > -} > - > #endif /* CONFIG_PRINTK_NMI */ > > -/* > - * Lock-less printk(), to avoid deadlocks should the printk() recurse > - * into itself. It uses a per-CPU buffer to store the message, just like > - * NMI. > - */ > -static __printf(1, 0) int vprintk_safe(const char *fmt, va_list args) > -{ > - struct printk_safe_seq_buf *s = this_cpu_ptr(&safe_print_seq); > - > - return printk_safe_log_store(s, fmt, args); > -} > - > /* Can be preempted by NMI. */ > void __printk_safe_enter(void) > { > @@ -369,7 +70,10 @@ __printf(1, 0) int vprintk_func(const char *fmt, va_list args) > * Use the main logbuf even in NMI. But avoid calling console > * drivers that might have their own locks. > */ > - if ((this_cpu_read(printk_context) & PRINTK_NMI_DIRECT_CONTEXT_MASK)) { > + if (this_cpu_read(printk_context) & > + (PRINTK_NMI_DIRECT_CONTEXT_MASK | > + PRINTK_NMI_CONTEXT_MASK | > + PRINTK_SAFE_CONTEXT_MASK)) { Do we need printk_nmi_direct_enter/exit() and PRINTK_NMI_DIRECT_CONTEXT_MASK? Seems like all printk_safe() paths are now DIRECT - we store messages to the prb, but don't call console drivers. -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=-8.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS 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 98332C433C1 for ; Sun, 21 Mar 2021 11:38:47 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (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 A48D5601FC for ; Sun, 21 Mar 2021 11:38:46 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A48D5601FC Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=chromium.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4F3FyD5ZPmz30BN for ; Sun, 21 Mar 2021 22:38:44 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; dkim=fail reason="signature verification failed" (1024-bit key; unprotected) header.d=chromium.org header.i=@chromium.org header.a=rsa-sha256 header.s=google header.b=CjBgjxTr; dkim-atps=neutral Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=chromium.org (client-ip=2607:f8b0:4864:20::42f; helo=mail-pf1-x42f.google.com; envelope-from=senozhatsky@chromium.org; receiver=) Authentication-Results: lists.ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=chromium.org header.i=@chromium.org header.a=rsa-sha256 header.s=google header.b=CjBgjxTr; dkim-atps=neutral Received: from mail-pf1-x42f.google.com (mail-pf1-x42f.google.com [IPv6:2607:f8b0:4864:20::42f]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4F35hc5NXSz2xfx for ; Sun, 21 Mar 2021 16:26:21 +1100 (AEDT) Received: by mail-pf1-x42f.google.com with SMTP id c204so8731205pfc.4 for ; Sat, 20 Mar 2021 22:26:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=Hh7shEFqN+4YQy0DWvjoXzsDlDCaLtw9ra44KHPWHkg=; b=CjBgjxTr+npHKRoZHWRNroG1zVN7+AkzcS/lmkSLNlF4EKxZnVNJjDShIuxxxAbDMP Zi7BM7SPsQiwW3sjUNxe7wSxx8345a5fj0NJPVkLBGCQUl1vmxZJ8jBKoC1wCrRzdvKX XajNGZiZipEMON2F1c0CexM5NZ+JccY+8RIow= 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; bh=Hh7shEFqN+4YQy0DWvjoXzsDlDCaLtw9ra44KHPWHkg=; b=PjkGNoS8O06TSycG5dfNg1ZKciNlvCbnM5amvuVNdcKdpD4u1WhcrKJjLrNt5IRNce 0O3t+Ow13gq0wzWrFA2I8dEeBDmzQ/wtsdPazGRPRGTx02n2/D74LAs0Uh8JZoImS/W7 gR2/ARuzh+v9c4BDEc5oZ8zbjve8ccWm1QaSi0SBFuCLzA8PPxQBoT5gwqjN+8TbEyw2 baO99aB4I5Ff3qIvhhmVlD/8i/owTtdf2CZXybNWlOrsQCXUq5ynh8ui4WfdM6Yc6rp5 vW7LgE2HvE9EBYK411nBbAjR1Y70PoofxGzKFkizHYw0TpgQuBaFUpCuZCo8KHVeZ8hp GPCA== X-Gm-Message-State: AOAM531K92wDDZWYZKGvfjNc4k+zkGN8gHX8yLV5YJl2LLCLYcMYNhOZ +Uwqy5w36KlmMqFF8HqqQTOSQw== X-Google-Smtp-Source: ABdhPJzWtY3HUJYpBDSoqpysrTRhl3hfq3Gue+pAzMn1TblrjdoVsbczMaY8+SWExQl6c3ccUGZpXA== X-Received: by 2002:a63:1845:: with SMTP id 5mr18028063pgy.244.1616304378263; Sat, 20 Mar 2021 22:26:18 -0700 (PDT) Received: from google.com ([2409:10:2e40:5100:2dfa:a0a:77ff:3953]) by smtp.gmail.com with ESMTPSA id x190sm9815525pfx.60.2021.03.20.22.26.12 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 20 Mar 2021 22:26:17 -0700 (PDT) Date: Sun, 21 Mar 2021 14:26:10 +0900 From: Sergey Senozhatsky To: John Ogness Subject: Re: [PATCH next v1 2/3] printk: remove safe buffers Message-ID: References: <20210316233326.10778-1-john.ogness@linutronix.de> <20210316233326.10778-3-john.ogness@linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210316233326.10778-3-john.ogness@linutronix.de> X-Mailman-Approved-At: Sun, 21 Mar 2021 22:38:19 +1100 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: Rafael Aquini , Peter Zijlstra , Paul Mackerras , Tiezhu Yang , Alexey Kardashevskiy , Yue Hu , Jordan Niethe , Petr Mladek , Kees Cook , "Paul E. McKenney" , Alistair Popple , "Guilherme G. Piccoli" , Nicholas Piggin , Steven Rostedt , Thomas Gleixner , kexec@lists.infradead.org, linux-kernel@vger.kernel.org, Eric Biederman , Andrew Morton , linuxppc-dev@lists.ozlabs.org, =?iso-8859-1?Q?C=E9dric?= Le Goater Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On (21/03/17 00:33), John Ogness wrote: [..] > void printk_nmi_direct_enter(void) > { > @@ -324,27 +44,8 @@ void printk_nmi_direct_exit(void) > this_cpu_and(printk_context, ~PRINTK_NMI_DIRECT_CONTEXT_MASK); > } > > -#else > - > -static __printf(1, 0) int vprintk_nmi(const char *fmt, va_list args) > -{ > - return 0; > -} > - > #endif /* CONFIG_PRINTK_NMI */ > > -/* > - * Lock-less printk(), to avoid deadlocks should the printk() recurse > - * into itself. It uses a per-CPU buffer to store the message, just like > - * NMI. > - */ > -static __printf(1, 0) int vprintk_safe(const char *fmt, va_list args) > -{ > - struct printk_safe_seq_buf *s = this_cpu_ptr(&safe_print_seq); > - > - return printk_safe_log_store(s, fmt, args); > -} > - > /* Can be preempted by NMI. */ > void __printk_safe_enter(void) > { > @@ -369,7 +70,10 @@ __printf(1, 0) int vprintk_func(const char *fmt, va_list args) > * Use the main logbuf even in NMI. But avoid calling console > * drivers that might have their own locks. > */ > - if ((this_cpu_read(printk_context) & PRINTK_NMI_DIRECT_CONTEXT_MASK)) { > + if (this_cpu_read(printk_context) & > + (PRINTK_NMI_DIRECT_CONTEXT_MASK | > + PRINTK_NMI_CONTEXT_MASK | > + PRINTK_SAFE_CONTEXT_MASK)) { Do we need printk_nmi_direct_enter/exit() and PRINTK_NMI_DIRECT_CONTEXT_MASK? Seems like all printk_safe() paths are now DIRECT - we store messages to the prb, but don't call console drivers. -ss From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail-pf1-x42b.google.com ([2607:f8b0:4864:20::42b]) by desiato.infradead.org with esmtps (Exim 4.94 #2 (Red Hat Linux)) id 1lNqbV-009cYZ-9m for kexec@lists.infradead.org; Sun, 21 Mar 2021 05:26:23 +0000 Received: by mail-pf1-x42b.google.com with SMTP id x26so8724052pfn.0 for ; Sat, 20 Mar 2021 22:26:19 -0700 (PDT) Date: Sun, 21 Mar 2021 14:26:10 +0900 From: Sergey Senozhatsky Subject: Re: [PATCH next v1 2/3] printk: remove safe buffers Message-ID: References: <20210316233326.10778-1-john.ogness@linutronix.de> <20210316233326.10778-3-john.ogness@linutronix.de> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20210316233326.10778-3-john.ogness@linutronix.de> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "kexec" Errors-To: kexec-bounces+dwmw2=infradead.org@lists.infradead.org To: John Ogness Cc: Petr Mladek , Steven Rostedt , Thomas Gleixner , linux-kernel@vger.kernel.org, Michael Ellerman , Benjamin Herrenschmidt , Paul Mackerras , Eric Biederman , Nicholas Piggin , Christophe Leroy , Alistair Popple , Jordan Niethe , Peter Zijlstra , =?iso-8859-1?Q?C=E9dric?= Le Goater , Andrew Morton , Kees Cook , Yue Hu , Alexey Kardashevskiy , Rafael Aquini , Tiezhu Yang , "Guilherme G. Piccoli" , "Paul E. McKenney" , linuxppc-dev@lists.ozlabs.org, kexec@lists.infradead.org On (21/03/17 00:33), John Ogness wrote: [..] > void printk_nmi_direct_enter(void) > { > @@ -324,27 +44,8 @@ void printk_nmi_direct_exit(void) > this_cpu_and(printk_context, ~PRINTK_NMI_DIRECT_CONTEXT_MASK); > } > > -#else > - > -static __printf(1, 0) int vprintk_nmi(const char *fmt, va_list args) > -{ > - return 0; > -} > - > #endif /* CONFIG_PRINTK_NMI */ > > -/* > - * Lock-less printk(), to avoid deadlocks should the printk() recurse > - * into itself. It uses a per-CPU buffer to store the message, just like > - * NMI. > - */ > -static __printf(1, 0) int vprintk_safe(const char *fmt, va_list args) > -{ > - struct printk_safe_seq_buf *s = this_cpu_ptr(&safe_print_seq); > - > - return printk_safe_log_store(s, fmt, args); > -} > - > /* Can be preempted by NMI. */ > void __printk_safe_enter(void) > { > @@ -369,7 +70,10 @@ __printf(1, 0) int vprintk_func(const char *fmt, va_list args) > * Use the main logbuf even in NMI. But avoid calling console > * drivers that might have their own locks. > */ > - if ((this_cpu_read(printk_context) & PRINTK_NMI_DIRECT_CONTEXT_MASK)) { > + if (this_cpu_read(printk_context) & > + (PRINTK_NMI_DIRECT_CONTEXT_MASK | > + PRINTK_NMI_CONTEXT_MASK | > + PRINTK_SAFE_CONTEXT_MASK)) { Do we need printk_nmi_direct_enter/exit() and PRINTK_NMI_DIRECT_CONTEXT_MASK? Seems like all printk_safe() paths are now DIRECT - we store messages to the prb, but don't call console drivers. -ss _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec