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serial: 8250_lpss: do not touch uninitialized line in ehl_serial_exit()

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lpss8250_probe() calls lpss->board->exit() on its error path. For the
EHL board, that is ehl_serial_exit() and it does:
serial8250_get_port(lpss->data.line)->dma = NULL;

But when lpss8250_dma_setup() or serial8250_register_8250_port() fails,
lpss->data.line was never assigned. As lpss is kzalloc()ed, line is 0
and ehl_serial_exit() clears the dma pointer of an unrelated port --
serial8250_ports[0], i.e. ttyS0, which is often the console.

Initialize lpss->data.line to -1 in probe and skip the clearing in
ehl_serial_exit() if no port was registered.

Fixes: 5318f70da7 ("serial: 8250_lpss: Balance reference count for PCI DMA device")
Signed-off-by: Jiri Slaby (SUSE) <jirislaby@kernel.org>
Assisted-by: LLM
Cc: "Ilpo Järvinen" <ilpo.jarvinen@linux.intel.com>
Cc: stable@kernel.org
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: linux-serial@vger.kernel.org
Link: https://patch.msgid.link/f389df34aaa538270313ebd4cea75c2baaf46b95.1791873876.git.jirislaby@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Jiri Slaby (SUSE) 2026-10-13 08:48:49 +02:00 committed by Greg Kroah-Hartman
parent 33d337816e
commit 3e3ae95a3d
1 changed files with 4 additions and 3 deletions
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7
drivers/tty/serial/8250/8250_lpss.c
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@ -183,9 +183,8 @@ static int ehl_serial_setup(struct lpss8250 *lpss, struct uart_port *port)
static void ehl_serial_exit(struct lpss8250 *lpss)
{
struct uart_8250_port *up = serial8250_get_port(lpss->data.line);
up->dma = NULL;
if (lpss->data.line >= 0)
serial8250_get_port(lpss->data.line)->dma = NULL;
}
#ifdef CONFIG_SERIAL_8250_DMA
@ -329,6 +328,8 @@ static int lpss8250_probe(struct pci_dev *pdev, const struct pci_device_id *id)
return ret;
lpss->board = (struct lpss8250_board *)id->driver_data;
/* for tests in lpss->board->exit() */
lpss->data.line = -1;
memset(&uart, 0, sizeof(struct uart_8250_port));