| From 4a8588a1cf867333187d9ff071e6fbdab587d194 Mon Sep 17 00:00:00 2001 |
| From: Stefan Agner <stefan@agner.ch> |
| Date: Sat, 10 Jan 2015 01:08:58 +0100 |
| Subject: serial: fsl_lpuart: delete timer on shutdown |
| |
| From: Stefan Agner <stefan@agner.ch> |
| |
| commit 4a8588a1cf867333187d9ff071e6fbdab587d194 upstream. |
| |
| If the serial port gets closed while a RX transfer is in progress, |
| the timer might fire after the serial port shutdown finished. This |
| leads in a NULL pointer dereference: |
| |
| [ 7.508324] Unable to handle kernel NULL pointer dereference at virtual address 00000000 |
| [ 7.516590] pgd = 86348000 |
| [ 7.519445] [00000000] *pgd=86179831, *pte=00000000, *ppte=00000000 |
| [ 7.526145] Internal error: Oops: 17 [#1] ARM |
| [ 7.530611] Modules linked in: |
| [ 7.533876] CPU: 0 PID: 123 Comm: systemd Not tainted 3.19.0-rc3-00004-g5b11ea7 #1778 |
| [ 7.541827] Hardware name: Freescale Vybrid VF610 (Device Tree) |
| [ 7.547862] task: 861c3400 ti: 86ac8000 task.ti: 86ac8000 |
| [ 7.553392] PC is at lpuart_timer_func+0x24/0xf8 |
| [ 7.558127] LR is at lpuart_timer_func+0x20/0xf8 |
| [ 7.562857] pc : [<802df99c>] lr : [<802df998>] psr: 600b0113 |
| [ 7.562857] sp : 86ac9b90 ip : 86ac9b90 fp : 86ac9bbc |
| [ 7.574467] r10: 80817180 r9 : 80817b98 r8 : 80817998 |
| [ 7.579803] r7 : 807acee0 r6 : 86989000 r5 : 00000100 r4 : 86997210 |
| [ 7.586444] r3 : 86ac8000 r2 : 86ac9bc0 r1 : 86997210 r0 : 00000000 |
| [ 7.593085] Flags: nZCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment user |
| [ 7.600341] Control: 10c5387d Table: 86348059 DAC: 00000015 |
| [ 7.606203] Process systemd (pid: 123, stack limit = 0x86ac8230) |
| |
| Setup the timer on UART startup which allows to delete the timer |
| unconditionally on shutdown. This also saves the initialization |
| on each transfer. |
| |
| Signed-off-by: Stefan Agner <stefan@agner.ch> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| drivers/tty/serial/fsl_lpuart.c | 7 ++++--- |
| 1 file changed, 4 insertions(+), 3 deletions(-) |
| |
| --- a/drivers/tty/serial/fsl_lpuart.c |
| +++ b/drivers/tty/serial/fsl_lpuart.c |
| @@ -506,9 +506,6 @@ static inline void lpuart_prepare_rx(str |
| |
| spin_lock_irqsave(&sport->port.lock, flags); |
| |
| - init_timer(&sport->lpuart_timer); |
| - sport->lpuart_timer.function = lpuart_timer_func; |
| - sport->lpuart_timer.data = (unsigned long)sport; |
| sport->lpuart_timer.expires = jiffies + sport->dma_rx_timeout; |
| add_timer(&sport->lpuart_timer); |
| |
| @@ -1106,6 +1103,8 @@ static int lpuart_startup(struct uart_po |
| sport->lpuart_dma_use = false; |
| } else { |
| sport->lpuart_dma_use = true; |
| + setup_timer(&sport->lpuart_timer, lpuart_timer_func, |
| + (unsigned long)sport); |
| temp = readb(port->membase + UARTCR5); |
| writeb(temp | UARTCR5_TDMAS, port->membase + UARTCR5); |
| } |
| @@ -1180,6 +1179,8 @@ static void lpuart_shutdown(struct uart_ |
| devm_free_irq(port->dev, port->irq, sport); |
| |
| if (sport->lpuart_dma_use) { |
| + del_timer_sync(&sport->lpuart_timer); |
| + |
| lpuart_dma_tx_free(port); |
| lpuart_dma_rx_free(port); |
| } |