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[109.81.89.112]) by smtp.gmail.com with UTF8SMTPSA id 5b1f17b1804b1-450cfbf42c1sm19208575e9.3.2025.05.29.05.26.32 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 29 May 2025 05:26:32 -0700 (PDT) Date: Thu, 29 May 2025 14:26:31 +0200 From: Michal Hocko To: "Kirill A. Shutemov" Cc: Andrew Morton , David Hildenbrand , lorenzo.stoakes@oracle.com, Liam.Howlett@oracle.com, vbabka@suse.cz, rppt@kernel.org, surenb@google.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Konstantin Khlebnikov Subject: Re: [PATCH] mm: Strictly check vmstat_text array size Message-ID: References: <20250529110541.2960330-1-kirill.shutemov@linux.intel.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250529110541.2960330-1-kirill.shutemov@linux.intel.com> On Thu 29-05-25 14:05:41, Kirill A. Shutemov wrote: > The /proc/vmstat displays counters from various sources. It is easy to > forget to add or remove a label when a new counter is added or removed. > > There is a BUILD_BUG_ON() function that catches missing labels. However, > for some reason, it ignores extra labels. > > Let's make the check strict. This would help to catch issues when > a counter is removed. > > Signed-off-by: Kirill A. Shutemov > Cc: Konstantin Khlebnikov LGTM Acked-by: Michal Hocko Not sure why we have gone with the current check TBH. > --- > mm/vmstat.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/mm/vmstat.c b/mm/vmstat.c > index ae9882063d89..0903adace423 100644 > --- a/mm/vmstat.c > +++ b/mm/vmstat.c > @@ -1867,7 +1867,7 @@ static void *vmstat_start(struct seq_file *m, loff_t *pos) > if (*pos >= NR_VMSTAT_ITEMS) > return NULL; > > - BUILD_BUG_ON(ARRAY_SIZE(vmstat_text) < NR_VMSTAT_ITEMS); > + BUILD_BUG_ON(ARRAY_SIZE(vmstat_text) != NR_VMSTAT_ITEMS); > fold_vm_numa_events(); > v = kmalloc_array(NR_VMSTAT_ITEMS, sizeof(unsigned long), GFP_KERNEL); > m->private = v; > -- > 2.47.2 -- Michal Hocko SUSE Labs