diff options
| author | Johan Hovold <johan@kernel.org> | 2023-02-27 09:50:46 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-03-09 17:08:05 +0100 |
| commit | 6e01f9a594ee0f69fb52cc8d11971612b4817f0b (patch) | |
| tree | 1cb46949b7c06282af9477dec03e5281abfd8f91 | |
| parent | 32e293be736b853f168cd065d9cbc1b0c69f545d (diff) | |
| download | lwn-6e01f9a594ee0f69fb52cc8d11971612b4817f0b.tar.gz lwn-6e01f9a594ee0f69fb52cc8d11971612b4817f0b.zip | |
serial: 8250_fsl: fix handle_irq locking
The 8250 handle_irq callback is not just called from the interrupt
handler but also from a timer callback when polling (e.g. for ports
without an interrupt line). Consequently the callback must explicitly
disable interrupts to avoid a potential deadlock with another interrupt
in polled mode.
Fix up the two paths in the freescale callback that failed to re-enable
interrupts when polling.
Fixes: 853a9ae29e97 ("serial: 8250: fix handle_irq locking")
Cc: stable@vger.kernel.org # 5.13
Reported-by: Dan Carpenter <error27@gmail.com>
Link: https://lore.kernel.org/r/Y/xYzqp4ogmOF5t0@kili
Signed-off-by: Johan Hovold <johan@kernel.org>
Acked-by: Jiri Slaby <jirislaby@kernel.org>
Link: https://lore.kernel.org/r/20230227085046.24282-1-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/tty/serial/8250/8250_fsl.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/tty/serial/8250/8250_fsl.c b/drivers/tty/serial/8250/8250_fsl.c index 8aad15622a2e..8adfaa183f77 100644 --- a/drivers/tty/serial/8250/8250_fsl.c +++ b/drivers/tty/serial/8250/8250_fsl.c @@ -34,7 +34,7 @@ int fsl8250_handle_irq(struct uart_port *port) iir = port->serial_in(port, UART_IIR); if (iir & UART_IIR_NO_INT) { - spin_unlock(&up->port.lock); + spin_unlock_irqrestore(&up->port.lock, flags); return 0; } @@ -42,7 +42,7 @@ int fsl8250_handle_irq(struct uart_port *port) if (unlikely(up->lsr_saved_flags & UART_LSR_BI)) { up->lsr_saved_flags &= ~UART_LSR_BI; port->serial_in(port, UART_RX); - spin_unlock(&up->port.lock); + spin_unlock_irqrestore(&up->port.lock, flags); return 1; } |