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Commit 963bfa57 authored by Sebastian Andrzej Siewior's avatar Sebastian Andrzej Siewior Committed by Greg Kroah-Hartman
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netfilter: nft_counter: Synchronize nft_counter_reset() against reader. 



[ Upstream commit a0b39e2dc7017ac667b70bdeee5293e410fab2fb ]

nft_counter_reset() resets the counter by subtracting the previously
retrieved value from the counter. This is a write operation on the
counter and as such it requires to be performed with a write sequence of
nft_counter_seq to serialize against its possible reader.

Update the packets/ bytes within write-sequence of nft_counter_seq.

Fixes: d84701ec ("netfilter: nft_counter: rework atomic dump and reset")
Signed-off-by: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: default avatarFlorian Westphal <fw@strlen.de>
Signed-off-by: default avatarPablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent 6633b178

net/netfilter/nft_counter.c

+5 −0
Original line number Diff line number Diff line
@@ -105,11 +105,16 @@ static void nft_counter_reset(struct nft_counter_percpu_priv *priv, 
			      struct nft_counter *total)

{

	struct nft_counter *this_cpu;

	seqcount_t *myseq;



	local_bh_disable();

	this_cpu = this_cpu_ptr(priv->counter);

	myseq = this_cpu_ptr(&nft_counter_seq);



	write_seqcount_begin(myseq);

	this_cpu->packets -= total->packets;

	this_cpu->bytes -= total->bytes;

	write_seqcount_end(myseq);

	local_bh_enable();

}