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

Submitted by Jia-Ju Bai on June 10, 2017, 9:03 a.m.

Details

Message ID 1497085415-630-1-git-send-email-baijiaju1990@163.com
State Accepted
Delegated to: David Miller
Headers show

Commit Message

Jia-Ju Bai June 10, 2017, 9:03 a.m.
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>
---
 net/tipc/msg.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Jon Paul Maloy June 10, 2017, 1:18 p.m.
Acked.

///jon


> -----Original Message-----
> From: Jia-Ju Bai [mailto:baijiaju1990@163.com]
> Sent: Saturday, June 10, 2017 05:04
> To: Jon Maloy <jon.maloy@ericsson.com>; Ying Xue
> <ying.xue@windriver.com>; davem@davemloft.net
> Cc: netdev@vger.kernel.org; tipc-discussion@lists.sourceforge.net; linux-
> kernel@vger.kernel.org; Jia-Ju Bai <baijiaju1990@163.com>
> Subject: [PATCH] net: tipc: Fix a sleep-in-atomic bug in tipc_msg_reverse
> 
> 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>
> ---
>  net/tipc/msg.c |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/net/tipc/msg.c b/net/tipc/msg.c index 312ef7d..ab30876 100644
> --- a/net/tipc/msg.c
> +++ b/net/tipc/msg.c
> @@ -508,7 +508,7 @@ bool tipc_msg_reverse(u32 own_node,  struct
> sk_buff **skb, int err)
>  	}
> 
>  	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 */
> --
> 1.7.9.5
>
David Miller June 10, 2017, 10:21 p.m.
From: Jia-Ju Bai <baijiaju1990@163.com>
Date: Sat, 10 Jun 2017 17:03:35 +0800

> 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>

Applied and queued up for -stable.

Patch hide | download patch | download mbox

diff --git a/net/tipc/msg.c b/net/tipc/msg.c
index 312ef7d..ab30876 100644
--- a/net/tipc/msg.c
+++ b/net/tipc/msg.c
@@ -508,7 +508,7 @@  bool tipc_msg_reverse(u32 own_node,  struct sk_buff **skb, int err)
 	}
 
 	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 */