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=-3.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 C6D7FC433E1 for ; Tue, 9 Jun 2020 04:32:00 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 88C1E207F9 for ; Tue, 9 Jun 2020 04:32:00 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="jBHUbyfo" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 88C1E207F9 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 2B3E46B009E; Tue, 9 Jun 2020 00:32:00 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 2657C6B00A0; Tue, 9 Jun 2020 00:32:00 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 17C696B00A1; Tue, 9 Jun 2020 00:32:00 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0130.hostedemail.com [216.40.44.130]) by kanga.kvack.org (Postfix) with ESMTP id F24CB6B009E for ; Tue, 9 Jun 2020 00:31:59 -0400 (EDT) Received: from smtpin08.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id B6639181ABEA4 for ; Tue, 9 Jun 2020 04:31:59 +0000 (UTC) X-FDA: 76908400758.08.rate73_000a7f126dbf Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin08.hostedemail.com (Postfix) with ESMTP id 919BF1819E627 for ; Tue, 9 Jun 2020 04:31:59 +0000 (UTC) X-HE-Tag: rate73_000a7f126dbf X-Filterd-Recvd-Size: 4711 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf25.hostedemail.com (Postfix) with ESMTP for ; Tue, 9 Jun 2020 04:31:59 +0000 (UTC) Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 2CB6620801; Tue, 9 Jun 2020 04:31:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591677118; bh=P0DlStunjxQkafwZoy5zsQayPjtOtLFFIoQYXvzpv/U=; h=Date:From:To:Subject:In-Reply-To:From; b=jBHUbyfoqxFJtqKWzGl/AIWj3Nm8CTfqIj6ClHaf3YxrwCSaqV813vF9QAFaMmuUB ccHN/KAfNfUkDCb7PbMxNJEqhfg20tjpbqRIKBa38X9A50619CDvNaTVOF2Pz1IK2H /pK2Qy8FlUaivwsd94JxHXqnVPNAiRqA1O/G2IAs= Date: Mon, 08 Jun 2020 21:31:57 -0700 From: Andrew Morton To: akpm@linux-foundation.org, bp@alien8.de, dima@arista.com, hpa@zytor.com, linux-mm@kvack.org, mingo@redhat.com, mm-commits@vger.kernel.org, tglx@linutronix.de, torvalds@linux-foundation.org Subject: [patch 40/93] x86: add missing const qualifiers for log_lvl Message-ID: <20200609043157.IJpJcnNBO%akpm@linux-foundation.org> In-Reply-To: <20200608212922.5b7fa74ca3f4e2444441b7f9@linux-foundation.org> User-Agent: s-nail v14.8.16 X-Rspamd-Queue-Id: 919BF1819E627 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam03 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: From: Dmitry Safonov Subject: x86: add missing const qualifiers for log_lvl Currently, the log-level of show_stack() depends on a platform realization. It creates situations where the headers are printed with lower log level or higher than the stacktrace (depending on a platform or user). Furthermore, it forces the logic decision from user to an architecture side. In result, some users as sysrq/kdb/etc are doing tricks with temporary rising console_loglevel while printing their messages. And in result it not only may print unwanted messages from other CPUs, but also omit printing at all in the unlucky case where the printk() was deferred. Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems an easier approach than introducing more printk buffers. Also, it will consolidate printings with headers. Keep log_lvl const show_trace_log_lvl() and printk_stack_address() as the new generic show_stack_loglvl() wants to have a proper const qualifier. And gcc rightfully produces warnings in case it's not keept: arch/x86/kernel/dumpstack.c: In function `show_stack': arch/x86/kernel/dumpstack.c:294:37: warning: passing argument 4 of `show_trace_log_lv ' discards `const' qualifier from pointer target type [-Wdiscarded-qualifiers] 294 | show_trace_log_lvl(task, NULL, sp, loglvl); | ^~~~~~ arch/x86/kernel/dumpstack.c:163:32: note: expected `char *' but argument is of type `const char *' 163 | unsigned long *stack, char *log_lvl) | ~~~~~~^~~~~~~ [1]: https://lore.kernel.org/lkml/20190528002412.1625-1-dima@arista.com/T/#u Link: http://lkml.kernel.org/r/20200418201944.482088-41-dima@arista.com Signed-off-by: Dmitry Safonov Cc: Borislav Petkov Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: Thomas Gleixner Signed-off-by: Andrew Morton --- arch/x86/include/asm/stacktrace.h | 2 +- arch/x86/kernel/dumpstack.c | 4 ++-- 2 files changed, 3 insertions(+), 3 deletions(-) --- a/arch/x86/include/asm/stacktrace.h~x86-add-missing-const-qualifiers-for-log_lvl +++ a/arch/x86/include/asm/stacktrace.h @@ -87,7 +87,7 @@ get_stack_pointer(struct task_struct *ta } void show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs, - unsigned long *stack, char *log_lvl); + unsigned long *stack, const char *log_lvl); /* The form of the top of the frame on the stack */ struct stack_frame { --- a/arch/x86/kernel/dumpstack.c~x86-add-missing-const-qualifiers-for-log_lvl +++ a/arch/x86/kernel/dumpstack.c @@ -65,7 +65,7 @@ bool in_entry_stack(unsigned long *stack } static void printk_stack_address(unsigned long address, int reliable, - char *log_lvl) + const char *log_lvl) { touch_nmi_watchdog(); printk("%s %s%pB\n", log_lvl, reliable ? "" : "? ", (void *)address); @@ -160,7 +160,7 @@ static void show_regs_if_on_stack(struct } void show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs, - unsigned long *stack, char *log_lvl) + unsigned long *stack, const char *log_lvl) { struct unwind_state state; struct stack_info stack_info = {0}; _