This is a note to let you know that I've just added the patch titled
serial: fsl_lpuart: delete timer on shutdown
to my tty git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty.git
in the tty-next branch.
The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)
The patch will also be merged in the next major kernel release
during the merge window.
If you have any questions about this process, please let me know.
>From 4a8588a1cf867333187d9ff071e6fbdab587d194 Mon Sep 17 00:00:00 2001
From: Stefan Agner <stefan@xxxxxxxx>
Date: Sat, 10 Jan 2015 01:08:58 +0100
Subject: serial: fsl_lpuart: delete timer on shutdown
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@xxxxxxxx>
Cc: stable <stable@xxxxxxxxxxxxxxx> # 3.14
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/tty/serial/fsl_lpuart.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c
index e7cde3a9566d..29932b73c004 100644
--- a/drivers/tty/serial/fsl_lpuart.c
+++ b/drivers/tty/serial/fsl_lpuart.c
@@ -506,9 +506,6 @@ static inline void lpuart_prepare_rx(struct lpuart_port *sport)
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_port *port)
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_port *port)
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);
}
--
2.2.2
--
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