4.19-stable review patch. If anyone has any objections, please let me know.
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From: Sebastian Andrzej Siewior bigeasy@linutronix.de
[ 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: d84701ecbcd6a ("netfilter: nft_counter: rework atomic dump and reset") Signed-off-by: Sebastian Andrzej Siewior bigeasy@linutronix.de Reviewed-by: Florian Westphal fw@strlen.de Signed-off-by: Pablo Neira Ayuso pablo@netfilter.org Signed-off-by: Sasha Levin sashal@kernel.org --- net/netfilter/nft_counter.c | 5 +++++ 1 file changed, 5 insertions(+)
diff --git a/net/netfilter/nft_counter.c b/net/netfilter/nft_counter.c index a61d7edfc290d..b4a4ed00506f1 100644 --- a/net/netfilter/nft_counter.c +++ b/net/netfilter/nft_counter.c @@ -108,11 +108,16 @@ static void nft_counter_reset(struct nft_counter_percpu_priv __percpu *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(); }