5.4-stable review patch. If anyone has any objections, please let me know.
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From: Krzysztof Kozlowski krzysztof.kozlowski@linaro.org
commit fc27ab48904ceb7e4792f0c400f1ef175edf16fe upstream.
Setting tty->disc_data before opening the NCI device means we need to clean it up on error paths. This also opens some short window if device starts sending data, even before NCIUARTSETDRIVER IOCTL succeeded (broken hardware?). Close the window by exposing tty->disc_data only on the success path, when opening of the NCI device and try_module_get() succeeds.
The code differs in error path in one aspect: tty->disc_data won't be ever assigned thus NULL-ified. This however should not be relevant difference, because of "tty->disc_data=NULL" in nci_uart_tty_open().
Cc: Linus Torvalds torvalds@linuxfoundation.org Fixes: 9961127d4bce ("NFC: nci: add generic uart support") Cc: stable@vger.kernel.org Signed-off-by: Krzysztof Kozlowski krzysztof.kozlowski@linaro.org Reviewed-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Link: https://patch.msgid.link/20250618073649.25049-2-krzysztof.kozlowski@linaro.o... Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/nfc/nci/uart.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)
--- a/net/nfc/nci/uart.c +++ b/net/nfc/nci/uart.c @@ -131,22 +131,22 @@ static int nci_uart_set_driver(struct tt
memcpy(nu, nci_uart_drivers[driver], sizeof(struct nci_uart)); nu->tty = tty; - tty->disc_data = nu; skb_queue_head_init(&nu->tx_q); INIT_WORK(&nu->write_work, nci_uart_write_work); spin_lock_init(&nu->rx_lock);
ret = nu->ops.open(nu); if (ret) { - tty->disc_data = NULL; kfree(nu); + return ret; } else if (!try_module_get(nu->owner)) { nu->ops.close(nu); - tty->disc_data = NULL; kfree(nu); return -ENOENT; } - return ret; + tty->disc_data = nu; + + return 0; }
/* ------ LDISC part ------ */