From f146e872eb12ebbe92d8e583b2637e0741440db3 Mon Sep 17 00:00:00 2001 From: Jia-Ju Bai Date: Sat, 10 Jun 2017 16:49:39 +0800 Subject: [PATCH] net: caif: Fix a sleep-in-atomic bug in cfpkt_create_pfx 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 Signed-off-by: David S. Miller --- net/caif/cfpkt_skbuff.c | 6 +----- 1 file changed, 1 insertion(+), 5 deletions(-) diff --git a/net/caif/cfpkt_skbuff.c b/net/caif/cfpkt_skbuff.c index 59ce1fcc220c..71b6ab240dea 100644 --- a/net/caif/cfpkt_skbuff.c +++ b/net/caif/cfpkt_skbuff.c @@ -81,11 +81,7 @@ static struct cfpkt *cfpkt_create_pfx(u16 len, u16 pfx) { 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;