Patch "net: tipc: Fix a sleep-in-atomic bug in tipc_msg_reverse" has been added to the 4.9-stable tree

Patch "net: tipc: Fix a sleep-in-atomic bug in tipc_msg_reverse" has been added to the 4.9-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    net: tipc: Fix a sleep-in-atomic bug in tipc_msg_reverse

to the 4.9-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     net-tipc-fix-a-sleep-in-atomic-bug-in-tipc_msg_reverse.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From foo@baz Thu Jun 29 18:57:46 CEST 2017
From: Jia-Ju Bai <baijiaju1990@163.com>
Date: Sat, 10 Jun 2017 17:03:35 +0800
Subject: net: tipc: Fix a sleep-in-atomic bug in tipc_msg_reverse

From: Jia-Ju Bai <baijiaju1990@163.com>


[ 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@163.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 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 */


Patches currently in stable-queue which might be from baijiaju1990@163.com are

queue-4.9/net-tipc-fix-a-sleep-in-atomic-bug-in-tipc_msg_reverse.patch
queue-4.9/net-caif-fix-a-sleep-in-atomic-bug-in-cfpkt_create_pfx.patch