[kbuild] [net-next:master 96/108] net/tipc/node.c:258 tipc_node_detach_link() error: buffer overflow 'n_ptr->links' 2 <= 2

[Dan Carpenter]

This is a style question and not a real bug:

Which is better:

OPTION #1: ignore static checker warnings

        for (i = 0; i < ARRAY_SIZE(x); i++) {
                if (found)
                        break;
        }
        x[i] = 0;


OPTION #2: stop on the last element

        for (i = 0; i < ARRAY_SIZE(x) - 1; i++) {
                if (found)
                        break;
        }
        x[i] = 0;


OPTION #3: add a bogus error test

        for (i = 0; i < ARRAY_SIZE(x); i++) {
                if (found)
                        break;
        }
        if (i == ARRAY_SIZE(x))
                return;
        x[i] = 0;

OPTION #4: convoluted code

        for (i = 0; i < ARRAY_SIZE(x); i++) {
                if (!found)
                        continue;
                x[i] = 0;
                break;
        }

It's not clear to me what the right answer is...

regards,
dan carpenter

-----

Hi Jon,

FYI, there are new smatch warnings show up in

tree:   git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next.git master
head:   d4f2fa6ad61ec1db713569a179183df4d0fc6ae7
commit: 7d33939f475d403e79124e3143d7951dcfe8629f [96/108] tipc: delay delete of 
link when failover is needed
:::::: branch date: 5 hours ago
:::::: commit date: 5 hours ago

net/tipc/node.c:258 tipc_node_detach_link() error: buffer overflow 
'n_ptr->links' 2 <= 2

git remote add net-next 
git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next.git
git remote update net-next
git checkout 7d33939f475d403e79124e3143d7951dcfe8629f
vim +258 net/tipc/node.c

b97bf3fd Per Liden       2006-01-02  242  
a18c4bc3 Paul Gortmaker  2011-12-29  243  void tipc_node_attach_link(struct 
tipc_node *n_ptr, struct tipc_link *l_ptr)
b97bf3fd Per Liden       2006-01-02  244  {
37b9c08a Allan Stephens  2011-02-28  245        
n_ptr->links[l_ptr->b_ptr->identity] = l_ptr;
37b9c08a Allan Stephens  2011-02-28  246        atomic_inc(&tipc_num_links);
37b9c08a Allan Stephens  2011-02-28  247        n_ptr->link_cnt++;
b97bf3fd Per Liden       2006-01-02  248  }
b97bf3fd Per Liden       2006-01-02  249  
a18c4bc3 Paul Gortmaker  2011-12-29  250  void tipc_node_detach_link(struct 
tipc_node *n_ptr, struct tipc_link *l_ptr)
b97bf3fd Per Liden       2006-01-02  251  {
7d33939f Jon Paul Maloy  2014-02-13  252        int i;
7d33939f Jon Paul Maloy  2014-02-13  253  
7d33939f Jon Paul Maloy  2014-02-13  254        for (i = 0; i < MAX_BEARERS; 
i++) {
7d33939f Jon Paul Maloy  2014-02-13  255                if (l_ptr == 
n_ptr->links[i])
7d33939f Jon Paul Maloy  2014-02-13  256                        break;
7d33939f Jon Paul Maloy  2014-02-13  257        }
7d33939f Jon Paul Maloy  2014-02-13 @258        n_ptr->links[i] = NULL;
d1bcb115 Allan Stephens  2011-02-25  259        atomic_dec(&tipc_num_links);
b97bf3fd Per Liden       2006-01-02  260        n_ptr->link_cnt--;
b97bf3fd Per Liden       2006-01-02  261  }
b97bf3fd Per Liden       2006-01-02  262  
6c00055a David S. Miller 2008-09-02  263  static void 
node_established_contact(struct tipc_node *n_ptr)
b97bf3fd Per Liden       2006-01-02  264  {
51a8e4de Allan Stephens  2010-12-31  265        
tipc_k_signal((Handler)tipc_named_node_up, n_ptr->addr);
c64f7a6a Jon Maloy       2012-11-16  266        n_ptr->bclink.oos_state = 0;

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