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=-8.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT 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 86A6BC32789 for ; Fri, 2 Nov 2018 13:32:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 404572081B for ; Fri, 2 Nov 2018 13:32:13 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 404572081B Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=I-love.SAKURA.ne.jp Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727790AbeKBWjV (ORCPT ); Fri, 2 Nov 2018 18:39:21 -0400 Received: from www262.sakura.ne.jp ([202.181.97.72]:55388 "EHLO www262.sakura.ne.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726026AbeKBWjV (ORCPT ); Fri, 2 Nov 2018 18:39:21 -0400 Received: from fsav105.sakura.ne.jp (fsav105.sakura.ne.jp [27.133.134.232]) by www262.sakura.ne.jp (8.15.2/8.15.2) with ESMTP id wA2DWAYE084888; Fri, 2 Nov 2018 22:32:10 +0900 (JST) (envelope-from penguin-kernel@I-love.SAKURA.ne.jp) Received: from www262.sakura.ne.jp (202.181.97.72) by fsav105.sakura.ne.jp (F-Secure/fsigk_smtp/530/fsav105.sakura.ne.jp); Fri, 02 Nov 2018 22:32:10 +0900 (JST) X-Virus-Status: clean(F-Secure/fsigk_smtp/530/fsav105.sakura.ne.jp) Received: from ccsecurity.localdomain (softbank060157065137.bbtec.net [60.157.65.137]) (authenticated bits=0) by www262.sakura.ne.jp (8.15.2/8.15.2) with ESMTPSA id wA2DW4kM084867 (version=TLSv1.2 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Fri, 2 Nov 2018 22:32:09 +0900 (JST) (envelope-from penguin-kernel@I-love.SAKURA.ne.jp) From: Tetsuo Handa To: Petr Mladek , Sergey Senozhatsky , Sergey Senozhatsky , Dmitriy Vyukov , Steven Rostedt Cc: Alexander Potapenko , Fengguang Wu , Josh Poimboeuf , LKML , Linus Torvalds , Andrew Morton , linux-mm@kvack.org, Ingo Molnar , Peter Zijlstra , Will Deacon , Tetsuo Handa Subject: [PATCH 2/3] mm: Use line-buffered printk() for show_free_areas(). Date: Fri, 2 Nov 2018 22:31:56 +0900 Message-Id: <1541165517-3557-2-git-send-email-penguin-kernel@I-love.SAKURA.ne.jp> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1541165517-3557-1-git-send-email-penguin-kernel@I-love.SAKURA.ne.jp> References: <1541165517-3557-1-git-send-email-penguin-kernel@I-love.SAKURA.ne.jp> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org syzbot is sometimes getting mixed output like below due to concurrent printk(). Mitigate such output by using line-buffered printk() API. Node 0 DMA: 1*4kB (U) 0*8kB 0*16kB 1*32kB syz-executor0: page allocation failure: order:0, mode:0x484020(GFP_ATOMIC|__GFP_COMP), nodemask=(null) (U) syz-executor0 cpuset= 2*64kB syz0 (U) mems_allowed=0 1*128kB CPU: 0 PID: 7592 Comm: syz-executor0 Not tainted 4.19.0-rc6+ #118 (U) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 1*256kB (U) Call Trace: 0*512kB 1*1024kB __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1c4/0x2b4 lib/dump_stack.c:113 (U) 1*2048kB warn_alloc.cold.119+0xb7/0x1bd mm/page_alloc.c:3426 (M) Signed-off-by: Tetsuo Handa Cc: Andrew Morton --- mm/page_alloc.c | 32 +++++++++++++++++--------------- 1 file changed, 17 insertions(+), 15 deletions(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index a919ba5..4411d5a 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -4694,10 +4694,10 @@ unsigned long nr_free_pagecache_pages(void) return nr_free_zone_pages(gfp_zone(GFP_HIGHUSER_MOVABLE)); } -static inline void show_node(struct zone *zone) +static inline void show_node(struct zone *zone, struct printk_buffer *buf) { if (IS_ENABLED(CONFIG_NUMA)) - printk("Node %d ", zone_to_nid(zone)); + printk_buffered(buf, "Node %d ", zone_to_nid(zone)); } long si_mem_available(void) @@ -4814,7 +4814,7 @@ static bool show_mem_node_skip(unsigned int flags, int nid, nodemask_t *nodemask #define K(x) ((x) << (PAGE_SHIFT-10)) -static void show_migration_types(unsigned char type) +static void show_migration_types(unsigned char type, struct printk_buffer *buf) { static const char types[MIGRATE_TYPES] = { [MIGRATE_UNMOVABLE] = 'U', @@ -4838,7 +4838,7 @@ static void show_migration_types(unsigned char type) } *p = '\0'; - printk(KERN_CONT "(%s) ", tmp); + printk_buffered(buf, "(%s) ", tmp); } /* @@ -4852,6 +4852,7 @@ static void show_migration_types(unsigned char type) */ void show_free_areas(unsigned int filter, nodemask_t *nodemask) { + struct printk_buffer *buf = get_printk_buffer(); unsigned long free_pcp = 0; int cpu; struct zone *zone; @@ -4950,8 +4951,8 @@ void show_free_areas(unsigned int filter, nodemask_t *nodemask) for_each_online_cpu(cpu) free_pcp += per_cpu_ptr(zone->pageset, cpu)->pcp.count; - show_node(zone); - printk(KERN_CONT + show_node(zone, buf); + printk_buffered(buf, "%s" " free:%lukB" " min:%lukB" @@ -4993,10 +4994,10 @@ void show_free_areas(unsigned int filter, nodemask_t *nodemask) K(free_pcp), K(this_cpu_read(zone->pageset->pcp.count)), K(zone_page_state(zone, NR_FREE_CMA_PAGES))); - printk("lowmem_reserve[]:"); + printk_buffered(buf, "lowmem_reserve[]:"); for (i = 0; i < MAX_NR_ZONES; i++) - printk(KERN_CONT " %ld", zone->lowmem_reserve[i]); - printk(KERN_CONT "\n"); + printk_buffered(buf, " %ld", zone->lowmem_reserve[i]); + printk_buffered(buf, "\n"); } for_each_populated_zone(zone) { @@ -5006,8 +5007,8 @@ void show_free_areas(unsigned int filter, nodemask_t *nodemask) if (show_mem_node_skip(filter, zone_to_nid(zone), nodemask)) continue; - show_node(zone); - printk(KERN_CONT "%s: ", zone->name); + show_node(zone, buf); + printk_buffered(buf, "%s: ", zone->name); spin_lock_irqsave(&zone->lock, flags); for (order = 0; order < MAX_ORDER; order++) { @@ -5025,12 +5026,12 @@ void show_free_areas(unsigned int filter, nodemask_t *nodemask) } spin_unlock_irqrestore(&zone->lock, flags); for (order = 0; order < MAX_ORDER; order++) { - printk(KERN_CONT "%lu*%lukB ", - nr[order], K(1UL) << order); + printk_buffered(buf, "%lu*%lukB ", + nr[order], K(1UL) << order); if (nr[order]) - show_migration_types(types[order]); + show_migration_types(types[order], buf); } - printk(KERN_CONT "= %lukB\n", K(total)); + printk_buffered(buf, "= %lukB\n", K(total)); } hugetlb_show_meminfo(); @@ -5038,6 +5039,7 @@ void show_free_areas(unsigned int filter, nodemask_t *nodemask) printk("%ld total pagecache pages\n", global_node_page_state(NR_FILE_PAGES)); show_swap_cache_info(); + put_printk_buffer(buf); } static void zoneref_set_zone(struct zone *zone, struct zoneref *zoneref) -- 1.8.3.1