5.15-stable review patch. If anyone has any objections, please let me know.
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From: Ryo Takakura ryotkkr98@gmail.com
commit e1ca3ff28ab1e2c1e70713ef3fa7943c725742c3 upstream.
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.
Fixes: 45c054d0815b ("tty: serial: add driver for the SiFive UART") Signed-off-by: Ryo Takakura ryotkkr98@gmail.com Reviewed-by: Petr Mladek pmladek@suse.com Cc: stable@vger.kernel.org Reviewed-by: John Ogness john.ogness@linutronix.de Rule: add Link: https://lore.kernel.org/stable/20250330003522.386632-1-ryotkkr98%40gmail.com Link: https://lore.kernel.org/r/20250412001847.183221-1-ryotkkr98@gmail.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/tty/serial/sifive.c | 6 ++++++ 1 file changed, 6 insertions(+)
--- a/drivers/tty/serial/sifive.c +++ b/drivers/tty/serial/sifive.c @@ -595,8 +595,11 @@ static void sifive_serial_break_ctl(stru 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; } @@ -604,9 +607,12 @@ static int sifive_serial_startup(struct 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); }
/**