diff options
| author | Johan Hovold <johan@kernel.org> | 2021-07-14 11:04:27 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-07-21 13:53:26 +0300 |
| commit | 853a9ae29e978d37f5dfa72622a68c9ae3d7fa89 (patch) | |
| tree | c3f2b62c6447e6b7fae006107281233aa99dfcce /drivers/tty/serial/8250 | |
| parent | cc9ca4d95846cbbece48d9cd385550f8fba6a3c1 (diff) | |
| download | linux-853a9ae29e978d37f5dfa72622a68c9ae3d7fa89.tar.xz | |
serial: 8250: 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.
Add back an irqrestore-version of the sysrq port-unlock helper and use
it in the 8250 callbacks that need it.
Fixes: 75f4e830fa9c ("serial: do not restore interrupt state in sysrq helper")
Cc: stable@vger.kernel.org # 5.13
Cc: Joel Stanley <joel@jms.id.au>
Cc: Andrew Jeffery <andrew@aj.id.au>
Reported-by: kernel test robot <oliver.sang@intel.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://lore.kernel.org/r/20210714080427.28164-1-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty/serial/8250')
| -rw-r--r-- | drivers/tty/serial/8250/8250_aspeed_vuart.c | 5 | ||||
| -rw-r--r-- | drivers/tty/serial/8250/8250_fsl.c | 5 | ||||
| -rw-r--r-- | drivers/tty/serial/8250/8250_port.c | 5 |
3 files changed, 9 insertions, 6 deletions
diff --git a/drivers/tty/serial/8250/8250_aspeed_vuart.c b/drivers/tty/serial/8250/8250_aspeed_vuart.c index 4caab8714e2c..2350fb3bb5e4 100644 --- a/drivers/tty/serial/8250/8250_aspeed_vuart.c +++ b/drivers/tty/serial/8250/8250_aspeed_vuart.c @@ -329,6 +329,7 @@ static int aspeed_vuart_handle_irq(struct uart_port *port) { struct uart_8250_port *up = up_to_u8250p(port); unsigned int iir, lsr; + unsigned long flags; unsigned int space, count; iir = serial_port_in(port, UART_IIR); @@ -336,7 +337,7 @@ static int aspeed_vuart_handle_irq(struct uart_port *port) if (iir & UART_IIR_NO_INT) return 0; - spin_lock(&port->lock); + spin_lock_irqsave(&port->lock, flags); lsr = serial_port_in(port, UART_LSR); @@ -370,7 +371,7 @@ static int aspeed_vuart_handle_irq(struct uart_port *port) if (lsr & UART_LSR_THRE) serial8250_tx_chars(up); - uart_unlock_and_check_sysrq(port); + uart_unlock_and_check_sysrq_irqrestore(port, flags); return 1; } diff --git a/drivers/tty/serial/8250/8250_fsl.c b/drivers/tty/serial/8250/8250_fsl.c index 4e75d2e4f87c..fc65a2293ce9 100644 --- a/drivers/tty/serial/8250/8250_fsl.c +++ b/drivers/tty/serial/8250/8250_fsl.c @@ -30,10 +30,11 @@ struct fsl8250_data { int fsl8250_handle_irq(struct uart_port *port) { unsigned char lsr, orig_lsr; + unsigned long flags; unsigned int iir; struct uart_8250_port *up = up_to_u8250p(port); - spin_lock(&up->port.lock); + spin_lock_irqsave(&up->port.lock, flags); iir = port->serial_in(port, UART_IIR); if (iir & UART_IIR_NO_INT) { @@ -82,7 +83,7 @@ int fsl8250_handle_irq(struct uart_port *port) up->lsr_saved_flags = orig_lsr; - uart_unlock_and_check_sysrq(&up->port); + uart_unlock_and_check_sysrq_irqrestore(&up->port, flags); return 1; } diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c index 2e7000f79b03..1da29a219842 100644 --- a/drivers/tty/serial/8250/8250_port.c +++ b/drivers/tty/serial/8250/8250_port.c @@ -1899,11 +1899,12 @@ int serial8250_handle_irq(struct uart_port *port, unsigned int iir) unsigned char status; struct uart_8250_port *up = up_to_u8250p(port); bool skip_rx = false; + unsigned long flags; if (iir & UART_IIR_NO_INT) return 0; - spin_lock(&port->lock); + spin_lock_irqsave(&port->lock, flags); status = serial_port_in(port, UART_LSR); @@ -1929,7 +1930,7 @@ int serial8250_handle_irq(struct uart_port *port, unsigned int iir) (up->ier & UART_IER_THRI)) serial8250_tx_chars(up); - uart_unlock_and_check_sysrq(port); + uart_unlock_and_check_sysrq_irqrestore(port, flags); return 1; } |