From 4cfb04854d053e4d6391d7f84495f48082342362 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Fri, 22 Feb 2013 07:43:35 +0000 Subject: [PATCH] net: fix possible deadlock in sum_frag_mem_limit Dave Jones reported a lockdep splat occurring in IP defrag code. commit 6d7b857d541ecd1d (net: use lib/percpu_counter API for fragmentation mem accounting) added a possible deadlock. Because percpu_counter_sum_positive() needs to acquire a lock that can be used from softirq, we need to disable BH in sum_frag_mem_limit() Reported-by: Dave Jones Signed-off-by: Eric Dumazet Cc: Jesper Dangaard Brouer Signed-off-by: David S. Miller --- include/net/inet_frag.h | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/include/net/inet_frag.h b/include/net/inet_frag.h index 3f237db0a426..76c3fe5ecc2e 100644 --- a/include/net/inet_frag.h +++ b/include/net/inet_frag.h @@ -114,7 +114,13 @@ static inline void init_frag_mem_limit(struct netns_frags *nf) static inline int sum_frag_mem_limit(struct netns_frags *nf) { - return percpu_counter_sum_positive(&nf->mem); + int res; + + local_bh_disable(); + res = percpu_counter_sum_positive(&nf->mem); + local_bh_enable(); + + return res; } static inline void inet_frag_lru_move(struct inet_frag_queue *q) -- 2.34.1