diff options
| author | Johannes Thumshirn <jthumshirn@suse.de> | 2015-08-06 09:16:37 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2015-09-21 10:10:53 -0700 |
| commit | f803126238a4d14067455a5a083055478a29a833 (patch) | |
| tree | d66d7021551a8e0bf6a4f00a5681f2a55e0a3aef | |
| parent | e611a710330e4c255b17500c9824fbaacb4d1e4a (diff) | |
tty: serial: men_z135_uart.c: Fix race between IRQ and set_termios()
commit 8117e347406278fd399b077add4e638cd017ae2d upstream.
Fix panic caused by a race between men_z135_intr() and men_z135_set_termios().
men_z135_intr() and men_z135_set_termios() both hold the struct uart_port::lock
spinlock, but men_z135_intr() does a spin_lock_irqsave() and
men_z135_set_termios() does a normal spin_lock(), which can lead to a deadlock
when an interrupt is called while the lock is being helt by
men_z135_set_termios().
This was discovered using a insmod, hardware looppback send/receive, rmmod
stress test.
Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Cc: Andreas Werner <andreas.werner@men.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/tty/serial/men_z135_uart.c | 9 |
1 files changed, 4 insertions, 5 deletions
diff --git a/drivers/tty/serial/men_z135_uart.c b/drivers/tty/serial/men_z135_uart.c index 35c55505b3eb..5a41b8fbb10a 100644 --- a/drivers/tty/serial/men_z135_uart.c +++ b/drivers/tty/serial/men_z135_uart.c @@ -392,7 +392,6 @@ static irqreturn_t men_z135_intr(int irq, void *data) struct men_z135_port *uart = (struct men_z135_port *)data; struct uart_port *port = &uart->port; bool handled = false; - unsigned long flags; int irq_id; uart->stat_reg = ioread32(port->membase + MEN_Z135_STAT_REG); @@ -401,7 +400,7 @@ static irqreturn_t men_z135_intr(int irq, void *data) if (!irq_id) goto out; - spin_lock_irqsave(&port->lock, flags); + spin_lock(&port->lock); /* It's save to write to IIR[7:6] RXC[9:8] */ iowrite8(irq_id, port->membase + MEN_Z135_STAT_REG); @@ -427,7 +426,7 @@ static irqreturn_t men_z135_intr(int irq, void *data) handled = true; } - spin_unlock_irqrestore(&port->lock, flags); + spin_unlock(&port->lock); out: return IRQ_RETVAL(handled); } @@ -717,7 +716,7 @@ static void men_z135_set_termios(struct uart_port *port, baud = uart_get_baud_rate(port, termios, old, 0, uart_freq / 16); - spin_lock(&port->lock); + spin_lock_irq(&port->lock); if (tty_termios_baud_rate(termios)) tty_termios_encode_baud_rate(termios, baud, baud); @@ -725,7 +724,7 @@ static void men_z135_set_termios(struct uart_port *port, iowrite32(bd_reg, port->membase + MEN_Z135_BAUD_REG); uart_update_timeout(port, termios->c_cflag, baud); - spin_unlock(&port->lock); + spin_unlock_irq(&port->lock); } static const char *men_z135_type(struct uart_port *port) |