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| author | Jakub Kicinski <kuba@kernel.org> | 2026-03-03 08:23:44 -0800 |
|---|---|---|
| committer | Sasha Levin <sashal@kernel.org> | 2026-03-12 07:09:57 -0400 |
| commit | 28c9be1ef8bb183e207978c487beafb3a99dafe4 (patch) | |
| tree | ce98c19365c3f004861fdef284c37d52bf089bed | |
| parent | d05f55d68ebdebb2b0a8480d766eaae88c8c92de (diff) | |
| download | linux-28c9be1ef8bb183e207978c487beafb3a99dafe4.tar.gz linux-28c9be1ef8bb183e207978c487beafb3a99dafe4.tar.bz2 linux-28c9be1ef8bb183e207978c487beafb3a99dafe4.zip | |
nfc: nci: clear NCI_DATA_EXCHANGE before calling completion callback
[ 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 <joe@dama.to>
Link: https://patch.msgid.link/20260303162346.2071888-5-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -rw-r--r-- | net/nfc/nci/data.c | 12 |
1 files changed, 8 insertions, 4 deletions
diff --git a/net/nfc/nci/data.c b/net/nfc/nci/data.c index 78f4131af3cf..5f98c73db5af 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 ----------------- */ |