From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-it1-f200.google.com (mail-it1-f200.google.com [209.85.166.200]) by kanga.kvack.org (Postfix) with ESMTP id 003F16B0266 for ; Mon, 15 Oct 2018 14:38:47 -0400 (EDT) Received: by mail-it1-f200.google.com with SMTP id m67-v6so18173926ita.8 for ; Mon, 15 Oct 2018 11:38:47 -0700 (PDT) Received: from mail-sor-f65.google.com (mail-sor-f65.google.com. [209.85.220.65]) by mx.google.com with SMTPS id k14-v6sor5177950iog.54.2018.10.15.11.38.47 for (Google Transport Security); Mon, 15 Oct 2018 11:38:47 -0700 (PDT) From: Yu Zhao Subject: [PATCH] mm: detect numbers of vmstat keys/values mismatch Date: Mon, 15 Oct 2018 12:38:41 -0600 Message-Id: <20181015183841.114341-1-yuzhao@google.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton , Michal Hocko Cc: Jan Kara , David Rientjes , Kemi Wang , Greg Kroah-Hartman , Steven Rostedt , Roman Gushchin , Kees Cook , Jann Horn , Andrey Ryabinin , Sebastian Andrzej Siewior , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Yu Zhao There were mismatches between number of vmstat keys and number of vmstat values. They were fixed recently by: commit 58bc4c34d249 ("mm/vmstat.c: skip NR_TLB_REMOTE_FLUSH* properly") commit 28e2c4bb99aa ("mm/vmstat.c: fix outdated vmstat_text") Add a BUILD_BUG_ON to detect such mismatch and hopefully prevent it from happening again. Signed-off-by: Yu Zhao --- include/linux/vmstat.h | 4 ++++ mm/vmstat.c | 18 ++++++++---------- 2 files changed, 12 insertions(+), 10 deletions(-) diff --git a/include/linux/vmstat.h b/include/linux/vmstat.h index f25cef84b41d..33fdd37124cb 100644 --- a/include/linux/vmstat.h +++ b/include/linux/vmstat.h @@ -78,6 +78,10 @@ extern void vm_events_fold_cpu(int cpu); #else +struct vm_event_state { + unsigned long event[0]; +}; + /* Disable counters */ static inline void count_vm_event(enum vm_event_item item) { diff --git a/mm/vmstat.c b/mm/vmstat.c index 7878da76abf2..7ebf871b4cc9 100644 --- a/mm/vmstat.c +++ b/mm/vmstat.c @@ -1647,23 +1647,21 @@ enum writeback_stat_item { NR_VM_WRITEBACK_STAT_ITEMS, }; +#define NR_VM_STAT_ITEMS (NR_VM_ZONE_STAT_ITEMS + NR_VM_NUMA_STAT_ITEMS + \ + NR_VM_NODE_STAT_ITEMS + NR_VM_WRITEBACK_STAT_ITEMS + \ + ARRAY_SIZE(((struct vm_event_state *)0)->event)) + static void *vmstat_start(struct seq_file *m, loff_t *pos) { + int i; unsigned long *v; - int i, stat_items_size; + + BUILD_BUG_ON(ARRAY_SIZE(vmstat_text) != NR_VM_STAT_ITEMS); if (*pos >= ARRAY_SIZE(vmstat_text)) return NULL; - stat_items_size = NR_VM_ZONE_STAT_ITEMS * sizeof(unsigned long) + - NR_VM_NUMA_STAT_ITEMS * sizeof(unsigned long) + - NR_VM_NODE_STAT_ITEMS * sizeof(unsigned long) + - NR_VM_WRITEBACK_STAT_ITEMS * sizeof(unsigned long); - -#ifdef CONFIG_VM_EVENT_COUNTERS - stat_items_size += sizeof(struct vm_event_state); -#endif - v = kmalloc(stat_items_size, GFP_KERNEL); + v = kmalloc_array(NR_VM_STAT_ITEMS, sizeof(unsigned long), GFP_KERNEL); m->private = v; if (!v) return ERR_PTR(-ENOMEM); -- 2.19.1.331.ge82ca0e54c-goog