| Message ID | 20241205143033.2695333-1-linux@roeck-us.net |
|---|---|
| State | New |
| Headers | show |
| Series | tty: serial: Work around warning backtrace in serial8250_set_defaults | expand |
On Thu, Dec 05, 2024 at 06:30:33AM -0800, Guenter Roeck wrote: > Commit 7c7e6c8924e7 ("tty: serial: handle HAS_IOPORT dependencies") > triggers warning backtraces on a number of platforms which don't support > IO ports. > > WARNING: CPU: 0 PID: 0 at drivers/tty/serial/8250/8250_port.c:470 serial8250_set_defaults+0x148/0x1d8 > Unsupported UART type 0 > > The problem is seen because serial8250_set_defaults() is called for > all members of the serial8250_ports[] array even if that array is > not initialized. > > Work around the problem by only displaying the warning if the port > type is not 0 (UPIO_PORT) or if iobase is set for the port. > > Fixes: 7c7e6c8924e7 ("tty: serial: handle HAS_IOPORT dependencies") > Acked-by: Arnd Bergmann <arnd@arndb.de> > Cc: Niklas Schnelle <schnelle@linux.ibm.com> > Signed-off-by: Guenter Roeck <linux@roeck-us.net> > --- > A complete fix will require a sequence of patches, which will have to be > tested thoroughly and is thus not 6.13 material. This patch doesn't fix > the underlying problem, but it is good enough for 6.13, or at least not > worse than 6.12, while at the same time avoiding the warning backtrace. This works on OpenRISC where I was seeing the issue. Has someone comitted to work on the root cause? Tested-by: Stafford Horne <shorne@gmail.com> > drivers/tty/serial/8250/8250_port.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c > index 4d63d80e78a9..649e74e9b52f 100644 > --- a/drivers/tty/serial/8250/8250_port.c > +++ b/drivers/tty/serial/8250/8250_port.c > @@ -467,7 +467,8 @@ static void set_io_from_upio(struct uart_port *p) > break; > #endif > default: > - WARN(1, "Unsupported UART type %x\n", p->iotype); > + WARN(p->iotype != UPIO_PORT || p->iobase, > + "Unsupported UART type %x\n", p->iotype); > p->serial_in = no_serial_in; > p->serial_out = no_serial_out; > } > -- > 2.45.2 > >
On Thu, Dec 05, 2024 at 07:12:42PM +0000, Stafford Horne wrote: > On Thu, Dec 05, 2024 at 06:30:33AM -0800, Guenter Roeck wrote: > > Commit 7c7e6c8924e7 ("tty: serial: handle HAS_IOPORT dependencies") > > triggers warning backtraces on a number of platforms which don't support > > IO ports. > > > > WARNING: CPU: 0 PID: 0 at drivers/tty/serial/8250/8250_port.c:470 serial8250_set_defaults+0x148/0x1d8 > > Unsupported UART type 0 > > > > The problem is seen because serial8250_set_defaults() is called for > > all members of the serial8250_ports[] array even if that array is > > not initialized. > > > > Work around the problem by only displaying the warning if the port > > type is not 0 (UPIO_PORT) or if iobase is set for the port. > > > > Fixes: 7c7e6c8924e7 ("tty: serial: handle HAS_IOPORT dependencies") > > Acked-by: Arnd Bergmann <arnd@arndb.de> > > Cc: Niklas Schnelle <schnelle@linux.ibm.com> > > Signed-off-by: Guenter Roeck <linux@roeck-us.net> > > --- > > A complete fix will require a sequence of patches, which will have to be > > tested thoroughly and is thus not 6.13 material. This patch doesn't fix > > the underlying problem, but it is good enough for 6.13, or at least not > > worse than 6.12, while at the same time avoiding the warning backtrace. > > This works on OpenRISC where I was seeing the issue. Has someone comitted to > work on the root cause? > Yes, Arnd is working on it. Guenter > Tested-by: Stafford Horne <shorne@gmail.com> > > > drivers/tty/serial/8250/8250_port.c | 3 ++- > > 1 file changed, 2 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c > > index 4d63d80e78a9..649e74e9b52f 100644 > > --- a/drivers/tty/serial/8250/8250_port.c > > +++ b/drivers/tty/serial/8250/8250_port.c > > @@ -467,7 +467,8 @@ static void set_io_from_upio(struct uart_port *p) > > break; > > #endif > > default: > > - WARN(1, "Unsupported UART type %x\n", p->iotype); > > + WARN(p->iotype != UPIO_PORT || p->iobase, > > + "Unsupported UART type %x\n", p->iotype); > > p->serial_in = no_serial_in; > > p->serial_out = no_serial_out; > > } > > -- > > 2.45.2 > > > >
On Thu, Dec 05, 2024 at 06:30:33AM -0800, Guenter Roeck wrote: > Commit 7c7e6c8924e7 ("tty: serial: handle HAS_IOPORT dependencies") > triggers warning backtraces on a number of platforms which don't support > IO ports. > > WARNING: CPU: 0 PID: 0 at drivers/tty/serial/8250/8250_port.c:470 serial8250_set_defaults+0x148/0x1d8 > Unsupported UART type 0 > > The problem is seen because serial8250_set_defaults() is called for > all members of the serial8250_ports[] array even if that array is > not initialized. > > Work around the problem by only displaying the warning if the port > type is not 0 (UPIO_PORT) or if iobase is set for the port. > > Fixes: 7c7e6c8924e7 ("tty: serial: handle HAS_IOPORT dependencies") > Acked-by: Arnd Bergmann <arnd@arndb.de> > Cc: Niklas Schnelle <schnelle@linux.ibm.com> > Signed-off-by: Guenter Roeck <linux@roeck-us.net> > --- > A complete fix will require a sequence of patches, which will have to be > tested thoroughly and is thus not 6.13 material. This patch doesn't fix > the underlying problem, but it is good enough for 6.13, or at least not > worse than 6.12, while at the same time avoiding the warning backtrace. Thanks, I'll take this for now. greg k-h
diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c index 4d63d80e78a9..649e74e9b52f 100644 --- a/drivers/tty/serial/8250/8250_port.c +++ b/drivers/tty/serial/8250/8250_port.c @@ -467,7 +467,8 @@ static void set_io_from_upio(struct uart_port *p) break; #endif default: - WARN(1, "Unsupported UART type %x\n", p->iotype); + WARN(p->iotype != UPIO_PORT || p->iobase, + "Unsupported UART type %x\n", p->iotype); p->serial_in = no_serial_in; p->serial_out = no_serial_out; }
Commit 7c7e6c8924e7 ("tty: serial: handle HAS_IOPORT dependencies") triggers warning backtraces on a number of platforms which don't support IO ports. WARNING: CPU: 0 PID: 0 at drivers/tty/serial/8250/8250_port.c:470 serial8250_set_defaults+0x148/0x1d8 Unsupported UART type 0 The problem is seen because serial8250_set_defaults() is called for all members of the serial8250_ports[] array even if that array is not initialized. Work around the problem by only displaying the warning if the port type is not 0 (UPIO_PORT) or if iobase is set for the port. Fixes: 7c7e6c8924e7 ("tty: serial: handle HAS_IOPORT dependencies") Acked-by: Arnd Bergmann <arnd@arndb.de> Cc: Niklas Schnelle <schnelle@linux.ibm.com> Signed-off-by: Guenter Roeck <linux@roeck-us.net> --- A complete fix will require a sequence of patches, which will have to be tested thoroughly and is thus not 6.13 material. This patch doesn't fix the underlying problem, but it is good enough for 6.13, or at least not worse than 6.12, while at the same time avoiding the warning backtrace. drivers/tty/serial/8250/8250_port.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)