This is a note to let you know that I've just added the patch titled
netfilter: nft_counter: Synchronize nft_counter_reset() against reader.
to the 5.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
netfilter-nft_counter-synchronize-nft_counter_reset-.patch
and it can be found in the queue-5.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 1384507cd1c1ae9ce8ae829a36111b5fcbed0094
Author: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
Date: Tue Aug 20 09:54:31 2024 +0200
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: d84701ecbcd6a ("netfilter: nft_counter: rework atomic dump and reset")
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
Reviewed-by: Florian Westphal <fw@xxxxxxxxx>
Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/net/netfilter/nft_counter.c b/net/netfilter/nft_counter.c
index f6d4d0fa23a62..bf829fabf2785 100644
--- a/net/netfilter/nft_counter.c
+++ b/net/netfilter/nft_counter.c
@@ -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();
}
