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 A35F13AA4FD; Mon, 23 Mar 2026 15:00:06 +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=1774278006; cv=none; b=RIu+Dfd4/PGpBCL6kTuWRJu4Kxpayo3zYghUTV+jksfcklyDnNd4vEb7j8Dt7khq3hY7iOUrO4W71DybYx8koS9Ia9t8RC735+pg5sHRYuSYe5hnH4e9yaELium5CRYofNhaDjsNay1Oa7fEp1pGr8OaHW+i5SxgN0nCACxSsk0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774278006; c=relaxed/simple; bh=mZEQ0Ye4b3E71FSwd5QtTB2O93ThNh6f3DKlbrhaLpg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=qkGWzDC7Ye4TLVycNmcf9hMM8Zae9Wz0d4Q+o0Ff/qBzIzbEfU4ea5MXDFYb8k4HcvUhRif5II4m6kZMTMyVkoHtnKppu9tLqq3GcRQE4XzUVzJrU6V4rKdn2/RVYG5HKnFpLjGdPZxjlHCwW62pkxHgHj6mMBRgWb3wpJB77Qk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=M/zf0Ik7; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="M/zf0Ik7" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1DEF0C4CEF7; Mon, 23 Mar 2026 15:00:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1774278006; bh=mZEQ0Ye4b3E71FSwd5QtTB2O93ThNh6f3DKlbrhaLpg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=M/zf0Ik7Kqt63TNf9W/psWjYGON+As8WFMwp87M+jQl+BKlvTV/Chuo89FacZzjo+ QJCYru/7GWOYrQquGOVISulaAByiY5jk1eQ+nYnnFtAGysVjrjCL4dKYWbqXgQQffS tz2N3i5cwLD2BOc1zTNCeczeLhlygk/U76SSDrp0= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Joe Damato , Jakub Kicinski , Sasha Levin Subject: [PATCH 6.6 170/567] nfc: nci: clear NCI_DATA_EXCHANGE before calling completion callback Date: Mon, 23 Mar 2026 14:41:30 +0100 Message-ID: <20260323134538.039410718@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260323134533.749096647@linuxfoundation.org> References: <20260323134533.749096647@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jakub Kicinski [ Upstream commit 0efdc02f4f6d52f8ca5d5889560f325a836ce0a8 ] 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") Reviewed-by: Joe Damato Link: https://patch.msgid.link/20260303162346.2071888-5-kuba@kernel.org Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- 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 3d36ea5701f02..7a3fb2a397a1e 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, del_timer_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 ----------------- */ -- 2.51.0