| From | Greg Kroah-Hartman <> | Subject | [PATCH 3.19 006/123] net_sched: fix struct tc_u_hnode layout in u32 | Date | Tue, 24 Mar 2015 16:45:15 +0100 |
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3.19-stable review patch. If anyone has any objections, please let me know.
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From: WANG Cong <xiyou.wangcong@gmail.com>
[ Upstream commit 5778d39d070b4ac5f889928175b7f2d53ae7504e ]
We dynamically allocate divisor+1 entries for ->ht[] in tc_u_hnode:
ht = kzalloc(sizeof(*ht) + divisor*sizeof(void *), GFP_KERNEL);
So ->ht is supposed to be the last field of this struct, however this is broken, since an rcu head is appended after it.
Fixes: 1ce87720d456 ("net: sched: make cls_u32 lockless") Cc: Jamal Hadi Salim <jhs@mojatatu.com> Cc: John Fastabend <john.fastabend@gmail.com> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- net/sched/cls_u32.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
--- a/net/sched/cls_u32.c +++ b/net/sched/cls_u32.c @@ -78,8 +78,11 @@ struct tc_u_hnode { struct tc_u_common *tp_c; int refcnt; unsigned int divisor; - struct tc_u_knode __rcu *ht[1]; struct rcu_head rcu; + /* The 'ht' field MUST be the last field in structure to allow for + * more entries allocated at end of structure. + */ + struct tc_u_knode __rcu *ht[1]; }; struct tc_u_common {
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