This is a note to let you know that I've just added the patch titled

net: Fix hlist corruptions in inet_evict_bucket()

to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: net-fix-hlist-corruptions-in-inet_evict_bucket.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@vger.kernel.org know about it.

From foo@baz Thu Mar 29 08:33:08 CEST 2018

From: Kirill Tkhai ktkhai@virtuozzo.com Date: Tue, 6 Mar 2018 18:46:39 +0300 Subject: net: Fix hlist corruptions in inet_evict_bucket()

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; }

Patches currently in stable-queue which might be from ktkhai@virtuozzo.com are

queue-4.4/net-fix-hlist-corruptions-in-inet_evict_bucket.patch