From: Joe Damato <joe@dama.to>
To: Jakub Kicinski <kuba@kernel.org>
Cc: davem@davemloft.net, netdev@vger.kernel.org, edumazet@google.com,
pabeni@redhat.com, andrew+netdev@lunn.ch, horms@kernel.org
Subject: Re: [PATCH net 4/5] nfc: nci: clear NCI_DATA_EXCHANGE before calling completion callback
Date: Tue, 3 Mar 2026 14:46:36 -0800 [thread overview]
Message-ID: <aadkzLW8Ba1Ej46V@devvm20253.cco0.facebook.com> (raw)
In-Reply-To: <20260303162346.2071888-5-kuba@kernel.org>
On Tue, Mar 03, 2026 at 08:23:44AM -0800, Jakub Kicinski wrote:
> Move clear_bit(NCI_DATA_EXCHANGE) before invoking the data exchange
> callback in nci_data_exchange_complete().
>
> The callback (e.g. rawsock_data_exchange_complete) may immediately
> schedule another data exchange via schedule_work(tx_work). On a
> multi-CPU system, tx_work can run and reach nci_transceive() before
> the current nci_data_exchange_complete() clears the flag, causing
> test_and_set_bit(NCI_DATA_EXCHANGE) to return -EBUSY and the new
> transfer to fail.
>
> This causes intermittent flakes in nci/nci_dev in NIPA:
>
> # # RUN NCI.NCI1_0.t4t_tag_read ...
> # # t4t_tag_read: Test terminated by timeout
> # # FAIL NCI.NCI1_0.t4t_tag_read
> # not ok 3 NCI.NCI1_0.t4t_tag_read
>
> Fixes: 38f04c6b1b68 ("NFC: protect nci_data_exchange transactions")
> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
> ---
> net/nfc/nci/data.c | 12 ++++++++----
> 1 file changed, 8 insertions(+), 4 deletions(-)
Reviewed-by: Joe Damato <joe@dama.to>
next prev parent reply other threads:[~2026-03-03 22:46 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-03 16:23 [PATCH net 0/5] nfc: fix leaks and races surfaced by NIPA Jakub Kicinski
2026-03-03 16:23 ` [PATCH net 1/5] nfc: nci: free skb on nci_transceive early error paths Jakub Kicinski
2026-03-03 21:02 ` Joe Damato
2026-03-03 16:23 ` [PATCH net 2/5] nfc: digital: free skb on digital_in_send " Jakub Kicinski
2026-03-03 21:04 ` Joe Damato
2026-03-03 16:23 ` [PATCH net 3/5] nfc: nci: complete pending data exchange on device close Jakub Kicinski
2026-03-03 22:03 ` Joe Damato
2026-03-03 16:23 ` [PATCH net 4/5] nfc: nci: clear NCI_DATA_EXCHANGE before calling completion callback Jakub Kicinski
2026-03-03 22:46 ` Joe Damato [this message]
2026-03-03 16:23 ` [PATCH net 5/5] nfc: rawsock: cancel tx_work before socket teardown Jakub Kicinski
2026-03-03 22:51 ` Joe Damato
2026-03-24 13:31 ` Guenter Roeck
2026-03-05 2:40 ` [PATCH net 0/5] nfc: fix leaks and races surfaced by NIPA patchwork-bot+netdevbpf
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