startup()/shutdown() callbacks access SIFIVE_SERIAL_IE_OFFS. The register is also accessed from write() callback.
If console were printing and startup()/shutdown() callback gets called, its access to the register could be overwritten.
Add port->lock to startup()/shutdown() callbacks to make sure their access to SIFIVE_SERIAL_IE_OFFS is synchronized against write() callback.
Signed-off-by: Ryo Takakura ryotkkr98@gmail.com Cc: stable@vger.kernel.org --- drivers/tty/serial/sifive.c | 6 ++++++ 1 file changed, 6 insertions(+)
diff --git a/drivers/tty/serial/sifive.c b/drivers/tty/serial/sifive.c index 5904a2d4c..054a8e630 100644 --- a/drivers/tty/serial/sifive.c +++ b/drivers/tty/serial/sifive.c @@ -563,8 +563,11 @@ static void sifive_serial_break_ctl(struct uart_port *port, int break_state) static int sifive_serial_startup(struct uart_port *port) { struct sifive_serial_port *ssp = port_to_sifive_serial_port(port); + unsigned long flags;
+ uart_port_lock_irqsave(&ssp->port, &flags); __ssp_enable_rxwm(ssp); + uart_port_unlock_irqrestore(&ssp->port, flags);
return 0; } @@ -572,9 +575,12 @@ static int sifive_serial_startup(struct uart_port *port) static void sifive_serial_shutdown(struct uart_port *port) { struct sifive_serial_port *ssp = port_to_sifive_serial_port(port); + unsigned long flags;
+ uart_port_lock_irqsave(&ssp->port, &flags); __ssp_disable_rxwm(ssp); __ssp_disable_txwm(ssp); + uart_port_unlock_irqrestore(&ssp->port, flags); }
/**
On Sat, Apr 05, 2025 at 01:43:38PM +0900, Ryo Takakura wrote:
startup()/shutdown() callbacks access SIFIVE_SERIAL_IE_OFFS. The register is also accessed from write() callback.
If console were printing and startup()/shutdown() callback gets called, its access to the register could be overwritten.
Add port->lock to startup()/shutdown() callbacks to make sure their access to SIFIVE_SERIAL_IE_OFFS is synchronized against write() callback.
Signed-off-by: Ryo Takakura ryotkkr98@gmail.com Cc: stable@vger.kernel.org
What commit id does this fix?
Why does patch 1/2 need to go to stable, but patch 2/2 does not? Please do not mix changes like this in the same series, otherwise we have to split them up manually when we apply them to the different branches, right?
thanks,
greg k-h
Hi Greg, thanks for the comments!
On Sat, 5 Apr 2025 08:35:44 +0100, Greg KH wrote:
On Sat, Apr 05, 2025 at 01:43:38PM +0900, Ryo Takakura wrote:
startup()/shutdown() callbacks access SIFIVE_SERIAL_IE_OFFS. The register is also accessed from write() callback.
If console were printing and startup()/shutdown() callback gets called, its access to the register could be overwritten.
Add port->lock to startup()/shutdown() callbacks to make sure their access to SIFIVE_SERIAL_IE_OFFS is synchronized against write() callback.
Signed-off-by: Ryo Takakura ryotkkr98@gmail.com Cc: stable@vger.kernel.org
What commit id does this fix?
I believe the issue existed ever since the driver was added by commit 45c054d0815b ("tty: serial: add driver for the SiFive UART").
Why does patch 1/2 need to go to stable, but patch 2/2 does not? Please
The patch 2/2 has nothing to do with existing issue and its only the patch 1/2 that needs to go to stable as discussed [0].
do not mix changes like this in the same series, otherwise we have to split them up manually when we apply them to the different branches, right?
I see, I'll keep this in mind. Let me resend the two separately with 'Fixes:' tag for the patch 1/2.
Sincerely, Ryo Takakura
thanks,
greg k-h
[0] https://lore.kernel.org/lkml/84sen2fo4b.fsf@jogness.linutronix.de/
linux-stable-mirror@lists.linaro.org
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Greg KH -
Ryo Takakura