From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 15E0E4E376E for ; Tue, 3 Mar 2026 16:23:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772555037; cv=none; b=qvIrHOwu+EAB6emlnExalOWxmnCUGp23LBjf2qY9VP6A4nVTN4BAl5zOQXupOTjEfhBQcrP3HQO1UzIzt7em7Mp+yWFMmPZDR5/U5sAMYF2UCjPyf0RasXf3ocPEhsXTDM27NQ7l1uY/QLv+O40J4MaaPXbH5HvIaBvsa7MHjc4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772555037; c=relaxed/simple; bh=zhqnPolAH4hQGlL7XelTk63vWvZyXRYQdMV/ytS0bMo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=C9wnZqy8mu2tep3Z1KDX9i9UcdMDUXwE7/Yyu0HhYnXi/hYcuUHNX5fjwXz0gWmeDF8X/618EZO7c0vozeD9N1VB172qEWxD07QkJcSUymxko17p7TUJnS4HjFOLLFaZjHowECN5LXDOQI3IrevEMLcQ5DQZ2X//N1/3QzgbvQ4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=thHbq060; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="thHbq060" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7A7DDC2BCAF; Tue, 3 Mar 2026 16:23:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1772555036; bh=zhqnPolAH4hQGlL7XelTk63vWvZyXRYQdMV/ytS0bMo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=thHbq060YB17Q0C5DVuZt0HXYlgX2jt1eqJ1xrMYm57sPE64GveaKLS/lFY8L0LW6 rNRHSiTAbKwxOVK2kanPx0BRr4oUvTiQfHjcDtA6UY9ez3ZE/FCSbDiptw9G/QsAt4 hDD/LhG2BBVL6DVrRWpmBT5WEBOz7iUSUAMVeUkc5Zs1wf+tNMn8Eu9pyb/jTkX0gk oegP1g37KA894Lr2sNKmnl/zpChL5vpnMJYeKL/lRJLDKE9kC1TpW0P1bt9DJfY2c2 CHBOHc5nZVHyS+iNd7By0KzDYMLKfxr7ZQXmbPrD/nF3zjn4aExiRvNaAjAwVUJYzl VG8iuPaPni99w== From: Jakub Kicinski To: davem@davemloft.net Cc: netdev@vger.kernel.org, edumazet@google.com, pabeni@redhat.com, andrew+netdev@lunn.ch, horms@kernel.org, Jakub Kicinski Subject: [PATCH net 4/5] nfc: nci: clear NCI_DATA_EXCHANGE before calling completion callback Date: Tue, 3 Mar 2026 08:23:44 -0800 Message-ID: <20260303162346.2071888-5-kuba@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260303162346.2071888-1-kuba@kernel.org> References: <20260303162346.2071888-1-kuba@kernel.org> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 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 --- net/nfc/nci/data.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/net/nfc/nci/data.c b/net/nfc/nci/data.c index 78f4131af3cf..efb001b41aa8 100644 --- a/net/nfc/nci/data.c +++ b/net/nfc/nci/data.c @@ -33,7 +33,8 @@ void nci_data_exchange_complete(struct nci_dev *ndev, struct sk_buff *skb, conn_info = nci_get_conn_info_by_conn_id(ndev, conn_id); if (!conn_info) { kfree_skb(skb); - goto exit; + clear_bit(NCI_DATA_EXCHANGE, &ndev->flags); + return; } cb = conn_info->data_exchange_cb; @@ -45,6 +46,12 @@ void nci_data_exchange_complete(struct nci_dev *ndev, struct sk_buff *skb, timer_delete_sync(&ndev->data_timer); clear_bit(NCI_DATA_EXCHANGE_TO, &ndev->flags); + /* Mark the exchange as done before calling the callback. + * The callback (e.g. rawsock_data_exchange_complete) may + * want to immediately queue another data exchange. + */ + clear_bit(NCI_DATA_EXCHANGE, &ndev->flags); + if (cb) { /* forward skb to nfc core */ cb(cb_context, skb, err); @@ -54,9 +61,6 @@ void nci_data_exchange_complete(struct nci_dev *ndev, struct sk_buff *skb, /* no waiting callback, free skb */ kfree_skb(skb); } - -exit: - clear_bit(NCI_DATA_EXCHANGE, &ndev->flags); } /* ----------------- NCI TX Data ----------------- */ -- 2.53.0