This is a note to let you know that I've just added the patch titled
net: caif: Fix a sleep-in-atomic bug in cfpkt_create_pfx
to the 4.4-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-caif-fix-a-sleep-in-atomic-bug-in-cfpkt_create_pfx.patch
and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From foo@baz Thu Jun 29 19:38:17 CEST 2017
From: Jia-Ju Bai <baijiaju1990@xxxxxxx>
Date: Sat, 10 Jun 2017 16:49:39 +0800
Subject: net: caif: Fix a sleep-in-atomic bug in cfpkt_create_pfx
From: Jia-Ju Bai <baijiaju1990@xxxxxxx>
[ Upstream commit f146e872eb12ebbe92d8e583b2637e0741440db3 ]
The kernel may sleep under a rcu read lock in cfpkt_create_pfx, and the
function call path is:
cfcnfg_linkup_rsp (acquire the lock by rcu_read_lock)
cfctrl_linkdown_req
cfpkt_create
cfpkt_create_pfx
alloc_skb(GFP_KERNEL) --> may sleep
cfserl_receive (acquire the lock by rcu_read_lock)
cfpkt_split
cfpkt_create_pfx
alloc_skb(GFP_KERNEL) --> may sleep
There is "in_interrupt" in cfpkt_create_pfx to decide use "GFP_KERNEL" or
"GFP_ATOMIC". In this situation, "GFP_KERNEL" is used because the function
is called under a rcu read lock, instead in interrupt.
To fix it, only "GFP_ATOMIC" is used in cfpkt_create_pfx.
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/caif/cfpkt_skbuff.c | 6 +-----
1 file changed, 1 insertion(+), 5 deletions(-)
--- a/net/caif/cfpkt_skbuff.c
+++ b/net/caif/cfpkt_skbuff.c
@@ -81,11 +81,7 @@ static struct cfpkt *cfpkt_create_pfx(u1
{
struct sk_buff *skb;
- if (likely(in_interrupt()))
- skb = alloc_skb(len + pfx, GFP_ATOMIC);
- else
- skb = alloc_skb(len + pfx, GFP_KERNEL);
-
+ skb = alloc_skb(len + pfx, GFP_ATOMIC);
if (unlikely(skb == NULL))
return NULL;
Patches currently in stable-queue which might be from baijiaju1990@xxxxxxx are
queue-4.4/net-caif-fix-a-sleep-in-atomic-bug-in-cfpkt_create_pfx.patch