4.4-stable review patch. If anyone has any objections, please let me know.
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From: Kirill Tkhai ktkhai@virtuozzo.com
[ Upstream commit a560002437d3646dafccecb1bf32d1685112ddda ]
inet_evict_bucket() iterates global list, and several tasks may call it in parallel. All of them hash the same fq->list_evictor to different lists, which leads to list corruption.
This patch makes fq be hashed to expired list only if this has not been made yet by another task. Since inet_frag_alloc() allocates fq using kmem_cache_zalloc(), we may rely on list_evictor is initially unhashed.
The problem seems to exist before async pernet_operations, as there was possible to have exit method to be executed in parallel with inet_frags::frags_work, so I add two Fixes tags. This also may go to stable.
Fixes: d1fe19444d82 "inet: frag: don't re-use chainlist for evictor" Fixes: f84c6821aa54 "net: Convert pernet_subsys, registered from inet_init()" Signed-off-by: Kirill Tkhai ktkhai@virtuozzo.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/ipv4/inet_fragment.c | 3 +++ 1 file changed, 3 insertions(+)
--- a/net/ipv4/inet_fragment.c +++ b/net/ipv4/inet_fragment.c @@ -119,6 +119,9 @@ out:
static bool inet_fragq_should_evict(const struct inet_frag_queue *q) { + if (!hlist_unhashed(&q->list_evictor)) + return false; + return q->net->low_thresh == 0 || frag_mem_limit(q->net) >= q->net->low_thresh; }