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    Subject[PATCH 4.14 195/218] serial: msm_serial: disable interrupts in __msm_console_write()
    Date
    From: John Ogness <john.ogness@linutronix.de>

    [ Upstream commit aabdbb1b7a5819e18c403334a31fb0cc2c06ad41 ]

    __msm_console_write() assumes that interrupts are disabled, but
    with threaded console printers it is possible that the write()
    callback of the console is called with interrupts enabled.

    Explicitly disable interrupts using local_irq_save() to preserve
    the assumed context.

    Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
    Reviewed-by: Petr Mladek <pmladek@suse.com>
    Signed-off-by: John Ogness <john.ogness@linutronix.de>
    Link: https://lore.kernel.org/r/20220506213324.470461-1-john.ogness@linutronix.de
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    drivers/tty/serial/msm_serial.c | 5 +++++
    1 file changed, 5 insertions(+)

    diff --git a/drivers/tty/serial/msm_serial.c b/drivers/tty/serial/msm_serial.c
    index 7848e9455950..3df3716caa56 100644
    --- a/drivers/tty/serial/msm_serial.c
    +++ b/drivers/tty/serial/msm_serial.c
    @@ -1587,6 +1587,7 @@ static inline struct uart_port *msm_get_port_from_line(unsigned int line)
    static void __msm_console_write(struct uart_port *port, const char *s,
    unsigned int count, bool is_uartdm)
    {
    + unsigned long flags;
    int i;
    int num_newlines = 0;
    bool replaced = false;
    @@ -1604,6 +1605,8 @@ static void __msm_console_write(struct uart_port *port, const char *s,
    num_newlines++;
    count += num_newlines;

    + local_irq_save(flags);
    +
    if (port->sysrq)
    locked = 0;
    else if (oops_in_progress)
    @@ -1649,6 +1652,8 @@ static void __msm_console_write(struct uart_port *port, const char *s,

    if (locked)
    spin_unlock(&port->lock);
    +
    + local_irq_restore(flags);
    }

    static void msm_console_write(struct console *co, const char *s,
    --
    2.35.1


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