Commit 4cfb0485 authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller

net: fix possible deadlock in sum_frag_mem_limit

Dave Jones reported a lockdep splat occurring in IP defrag code.

commit 6d7b857d (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: default avatarDave Jones <davej@redhat.com>
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent e2f8d555
...@@ -114,7 +114,13 @@ static inline void init_frag_mem_limit(struct netns_frags *nf) ...@@ -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) 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) static inline void inet_frag_lru_move(struct inet_frag_queue *q)
......
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