| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.4 164/241] cxgb3/l2t: Fix undefined behaviour | Date | Sun, 9 Jun 2019 18:41:46 +0200 |
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[ Upstream commit 76497732932f15e7323dc805e8ea8dc11bb587cf ]
The use of zero-sized array causes undefined behaviour when it is not the last member in a structure. As it happens to be in this case.
Also, the current code makes use of a language extension to the C90 standard, but the preferred mechanism to declare variable-length types such as this one is a flexible array member, introduced in C99:
struct foo { int stuff; struct boo array[]; };
By making use of the mechanism above, we will get a compiler warning in case the flexible array does not occur last. Which is beneficial to cultivate a high-quality code.
Fixes: e48f129c2f20 ("[SCSI] cxgb3i: convert cdev->l2opt to use rcu to prevent NULL dereference") Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org> --- drivers/net/ethernet/chelsio/cxgb3/l2t.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/net/ethernet/chelsio/cxgb3/l2t.h b/drivers/net/ethernet/chelsio/cxgb3/l2t.h index 8cffcdfd56782..38b5858c335a9 100644 --- a/drivers/net/ethernet/chelsio/cxgb3/l2t.h +++ b/drivers/net/ethernet/chelsio/cxgb3/l2t.h @@ -75,8 +75,8 @@ struct l2t_data { struct l2t_entry *rover; /* starting point for next allocation */ atomic_t nfree; /* number of free entries */ rwlock_t lock; - struct l2t_entry l2tab[0]; struct rcu_head rcu_head; /* to handle rcu cleanup */ + struct l2t_entry l2tab[]; }; typedef void (*arp_failure_handler_func)(struct t3cdev * dev, -- 2.20.1
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