4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Jia-Ju Bai <baijiaju1990@xxxxxxx>
[ Upstream commit 343eba69c6968190d8654b857aea952fed9a6749 ]
The kernel may sleep under a rcu read lock in tipc_msg_reverse, and the
function call path is:
tipc_l2_rcv_msg (acquire the lock by rcu_read_lock)
tipc_rcv
tipc_sk_rcv
tipc_msg_reverse
pskb_expand_head(GFP_KERNEL) --> may sleep
tipc_node_broadcast
tipc_node_xmit_skb
tipc_node_xmit
tipc_sk_rcv
tipc_msg_reverse
pskb_expand_head(GFP_KERNEL) --> may sleep
To fix it, "GFP_KERNEL" is replaced with "GFP_ATOMIC".
Signed-off-by: Jia-Ju Bai <baijiaju1990@xxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/tipc/msg.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/net/tipc/msg.c
+++ b/net/tipc/msg.c
@@ -508,7 +508,7 @@ bool tipc_msg_reverse(u32 own_node, str
}
if (skb_cloned(_skb) &&
- pskb_expand_head(_skb, BUF_HEADROOM, BUF_TAILROOM, GFP_KERNEL))
+ pskb_expand_head(_skb, BUF_HEADROOM, BUF_TAILROOM, GFP_ATOMIC))
goto exit;
/* Now reverse the concerned fields */