netdev - [net-next:master 200/201] net/ipv4/inet_hashtables.c:620:13: warning: division by zero

Open Source and information security mailing list archives

Date:	Wed, 27 May 2015 12:09:26 +0800
From:	kbuild test robot <fengguang.wu@...el.com>
To:	Eric Dumazet <edumazet@...gle.com>
Cc:	kbuild-all@...org, netdev@...r.kernel.org
Subject: [net-next:master 200/201] net/ipv4/inet_hashtables.c:620:13:
 warning: division by zero

tree:   git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next.git master
head:   d6a4e26afb80c049e7f94e1b7b506dcda61eee88
commit: 095dc8e0c3686d586a01a50abc3e1bb9ac633054 [200/201] tcp: fix/cleanup inet_ehash_locks_alloc()
config: cris-etrax-100lx_v2_defconfig (attached as .config)
reproduce:
  wget https://git.kernel.org/cgit/linux/kernel/git/wfg/lkp-tests.git/plain/sbin/make.cross -O ~/bin/make.cross
  chmod +x ~/bin/make.cross
  git checkout 095dc8e0c3686d586a01a50abc3e1bb9ac633054
  # save the attached .config to linux build tree
  make.cross ARCH=cris 

All warnings:

   net/ipv4/inet_hashtables.c: In function 'inet_ehash_locks_alloc':
>> net/ipv4/inet_hashtables.c:620:13: warning: division by zero [-Wdiv-by-zero]

vim +620 net/ipv4/inet_hashtables.c

   604		int i;
   605	
   606		for (i = 0; i < INET_LHTABLE_SIZE; i++) {
   607			spin_lock_init(&h->listening_hash[i].lock);
   608			INIT_HLIST_NULLS_HEAD(&h->listening_hash[i].head,
   609					      i + LISTENING_NULLS_BASE);
   610			}
   611	}
   612	EXPORT_SYMBOL_GPL(inet_hashinfo_init);
   613	
   614	int inet_ehash_locks_alloc(struct inet_hashinfo *hashinfo)
   615	{
   616		unsigned int i, nblocks = 1;
   617	
   618		if (sizeof(spinlock_t) != 0) {
   619			/* allocate 2 cache lines or at least one spinlock per cpu */
 > 620			nblocks = max_t(unsigned int,
   621					2 * L1_CACHE_BYTES / sizeof(spinlock_t),
   622					1);
   623			nblocks = roundup_pow_of_two(nblocks * num_possible_cpus());
   624	
   625			/* no more locks than number of hash buckets */
   626			nblocks = min(nblocks, hashinfo->ehash_mask + 1);
   627	
   628			hashinfo->ehash_locks =	kmalloc_array(nblocks, sizeof(spinlock_t),

---
0-DAY kernel test infrastructure                Open Source Technology Center
http://lists.01.org/mailman/listinfo/kbuild                 Intel Corporation

View attachment ".config" of type "text/plain" (28812 bytes)

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives