Hi Johan, Yes, there is no deadlock. my fault. I forget the local_irq_save() plus spin_lock() is spin_lock_irqsave(). Thanks for your review. please ignore this patch. Best regards Dillon On Mon, Apr 12, 2021 at 9:08 PM Johan Hovold <johan@xxxxxxxxxx> wrote: > > On Mon, Apr 12, 2021 at 05:31:38PM +0800, dillon.minfei@xxxxxxxxx wrote: > > From: dillon min <dillon.minfei@xxxxxxxxx> > > > > To avoid potential deadlock in spin_lock usage, use spin_lock_irqsave, > > spin_trylock_irqsave(), spin_unlock_irqrestore() in process context. > > This doesn't make much sense as console_write can be called in any > context. And where's the deadlock you claim to be fixing here? > > > remove unused local_irq_save/restore call. > > > > Cc: Alexandre Torgue <alexandre.torgue@xxxxxxxxxxx> > > Cc: Maxime Coquelin <mcoquelin.stm32@xxxxxxxxx> > > Cc: Gerald Baeza <gerald.baeza@xxxxxxxxxxx> > > Cc: Erwan Le Ray <erwan.leray@xxxxxxxxxxx> > > Reported-by: kernel test robot <lkp@xxxxxxxxx> > > Signed-off-by: dillon min <dillon.minfei@xxxxxxxxx> > > --- > > v2: remove unused code from stm32_usart_threaded_interrupt() according from > > Greg's review. > > > > drivers/tty/serial/stm32-usart.c | 8 +++----- > > 1 file changed, 3 insertions(+), 5 deletions(-) > > > > diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c > > index b3675cf25a69..b1ba5e36e36e 100644 > > --- a/drivers/tty/serial/stm32-usart.c > > +++ b/drivers/tty/serial/stm32-usart.c > > @@ -1354,13 +1354,12 @@ static void stm32_usart_console_write(struct console *co, const char *s, > > u32 old_cr1, new_cr1; > > int locked = 1; > > > > - local_irq_save(flags); > > if (port->sysrq) > > locked = 0; > > else if (oops_in_progress) > > - locked = spin_trylock(&port->lock); > > + locked = spin_trylock_irqsave(&port->lock, flags); > > else > > - spin_lock(&port->lock); > > + spin_lock_irqsave(&port->lock, flags); > > > > /* Save and disable interrupts, enable the transmitter */ > > old_cr1 = readl_relaxed(port->membase + ofs->cr1); > > @@ -1374,8 +1373,7 @@ static void stm32_usart_console_write(struct console *co, const char *s, > > writel_relaxed(old_cr1, port->membase + ofs->cr1); > > > > if (locked) > > - spin_unlock(&port->lock); > > - local_irq_restore(flags); > > + spin_unlock_irqrestore(&port->lock, flags); > > } > > > > static int stm32_usart_console_setup(struct console *co, char *options) > > Johan
