| Message ID | 1411545322-22940-2-git-send-email-frans.klaver@xsens.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Wed, Sep 24, 2014 at 09:55:21AM +0200, Frans Klaver wrote: > If the chosen baud rate is large enough (e.g. 3.5 megabaud), the > calculated n values in serial_omap_is_baud_mode16() may become 0. This > causes a division by zero when calculating the difference between > calculated and desired baud rates. To prevent this, cap the n13 and n16 > values on 1. > > Division by zero in kernel. > [<c00132e0>] (unwind_backtrace) from [<c00112ec>] (show_stack+0x10/0x14) > [<c00112ec>] (show_stack) from [<c01ed7bc>] (Ldiv0+0x8/0x10) > [<c01ed7bc>] (Ldiv0) from [<c023805c>] (serial_omap_baud_is_mode16+0x4c/0x68) > [<c023805c>] (serial_omap_baud_is_mode16) from [<c02396b4>] (serial_omap_set_termios+0x90/0x8d8) > [<c02396b4>] (serial_omap_set_termios) from [<c0230a0c>] (uart_change_speed+0xa4/0xa8) > [<c0230a0c>] (uart_change_speed) from [<c0231798>] (uart_set_termios+0xa0/0x1fc) > [<c0231798>] (uart_set_termios) from [<c022bb44>] (tty_set_termios+0x248/0x2c0) > [<c022bb44>] (tty_set_termios) from [<c022c17c>] (set_termios+0x248/0x29c) > [<c022c17c>] (set_termios) from [<c022c3e4>] (tty_mode_ioctl+0x1c8/0x4e8) > [<c022c3e4>] (tty_mode_ioctl) from [<c0227e70>] (tty_ioctl+0xa94/0xb18) > [<c0227e70>] (tty_ioctl) from [<c00cf45c>] (do_vfs_ioctl+0x4a0/0x560) > [<c00cf45c>] (do_vfs_ioctl) from [<c00cf568>] (SyS_ioctl+0x4c/0x74) > [<c00cf568>] (SyS_ioctl) from [<c000e480>] (ret_fast_syscall+0x0/0x30) > > Signed-off-by: Frans Klaver <frans.klaver@xsens.com> > --- > drivers/tty/serial/omap-serial.c | 12 ++++++++++-- > 1 file changed, 10 insertions(+), 2 deletions(-) Should this go to the stable kernel trees as well? thanks, greg k-h -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Wed, Sep 24, 2014 at 01:08:52AM -0700, Greg Kroah-Hartman wrote: > On Wed, Sep 24, 2014 at 09:55:21AM +0200, Frans Klaver wrote: > > If the chosen baud rate is large enough (e.g. 3.5 megabaud), the > > calculated n values in serial_omap_is_baud_mode16() may become 0. This > > causes a division by zero when calculating the difference between > > calculated and desired baud rates. To prevent this, cap the n13 and n16 > > values on 1. > > > > Division by zero in kernel. > > [<c00132e0>] (unwind_backtrace) from [<c00112ec>] (show_stack+0x10/0x14) > > [<c00112ec>] (show_stack) from [<c01ed7bc>] (Ldiv0+0x8/0x10) > > [<c01ed7bc>] (Ldiv0) from [<c023805c>] (serial_omap_baud_is_mode16+0x4c/0x68) > > [<c023805c>] (serial_omap_baud_is_mode16) from [<c02396b4>] (serial_omap_set_termios+0x90/0x8d8) > > [<c02396b4>] (serial_omap_set_termios) from [<c0230a0c>] (uart_change_speed+0xa4/0xa8) > > [<c0230a0c>] (uart_change_speed) from [<c0231798>] (uart_set_termios+0xa0/0x1fc) > > [<c0231798>] (uart_set_termios) from [<c022bb44>] (tty_set_termios+0x248/0x2c0) > > [<c022bb44>] (tty_set_termios) from [<c022c17c>] (set_termios+0x248/0x29c) > > [<c022c17c>] (set_termios) from [<c022c3e4>] (tty_mode_ioctl+0x1c8/0x4e8) > > [<c022c3e4>] (tty_mode_ioctl) from [<c0227e70>] (tty_ioctl+0xa94/0xb18) > > [<c0227e70>] (tty_ioctl) from [<c00cf45c>] (do_vfs_ioctl+0x4a0/0x560) > > [<c00cf45c>] (do_vfs_ioctl) from [<c00cf568>] (SyS_ioctl+0x4c/0x74) > > [<c00cf568>] (SyS_ioctl) from [<c000e480>] (ret_fast_syscall+0x0/0x30) > > > > Signed-off-by: Frans Klaver <frans.klaver@xsens.com> > > --- > > drivers/tty/serial/omap-serial.c | 12 ++++++++++-- > > 1 file changed, 10 insertions(+), 2 deletions(-) > > Should this go to the stable kernel trees as well? It's been there for a while. Introduced in 5fe2123647c1508 "OMAP/serial: Support 1Mbaud and similar baudrates that require Mode16 instead of Mode13" (v3.9). It's probably a good idea to do so. stable@... needs a cc? Frans -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Wed, Sep 24, 2014 at 10:41:11AM +0200, Frans Klaver wrote: > On Wed, Sep 24, 2014 at 01:08:52AM -0700, Greg Kroah-Hartman wrote: > > On Wed, Sep 24, 2014 at 09:55:21AM +0200, Frans Klaver wrote: > > > If the chosen baud rate is large enough (e.g. 3.5 megabaud), the > > > calculated n values in serial_omap_is_baud_mode16() may become 0. This > > > causes a division by zero when calculating the difference between > > > calculated and desired baud rates. To prevent this, cap the n13 and n16 > > > values on 1. > > > > > > Division by zero in kernel. > > > [<c00132e0>] (unwind_backtrace) from [<c00112ec>] (show_stack+0x10/0x14) > > > [<c00112ec>] (show_stack) from [<c01ed7bc>] (Ldiv0+0x8/0x10) > > > [<c01ed7bc>] (Ldiv0) from [<c023805c>] (serial_omap_baud_is_mode16+0x4c/0x68) > > > [<c023805c>] (serial_omap_baud_is_mode16) from [<c02396b4>] (serial_omap_set_termios+0x90/0x8d8) > > > [<c02396b4>] (serial_omap_set_termios) from [<c0230a0c>] (uart_change_speed+0xa4/0xa8) > > > [<c0230a0c>] (uart_change_speed) from [<c0231798>] (uart_set_termios+0xa0/0x1fc) > > > [<c0231798>] (uart_set_termios) from [<c022bb44>] (tty_set_termios+0x248/0x2c0) > > > [<c022bb44>] (tty_set_termios) from [<c022c17c>] (set_termios+0x248/0x29c) > > > [<c022c17c>] (set_termios) from [<c022c3e4>] (tty_mode_ioctl+0x1c8/0x4e8) > > > [<c022c3e4>] (tty_mode_ioctl) from [<c0227e70>] (tty_ioctl+0xa94/0xb18) > > > [<c0227e70>] (tty_ioctl) from [<c00cf45c>] (do_vfs_ioctl+0x4a0/0x560) > > > [<c00cf45c>] (do_vfs_ioctl) from [<c00cf568>] (SyS_ioctl+0x4c/0x74) > > > [<c00cf568>] (SyS_ioctl) from [<c000e480>] (ret_fast_syscall+0x0/0x30) > > > > > > Signed-off-by: Frans Klaver <frans.klaver@xsens.com> > > > --- > > > drivers/tty/serial/omap-serial.c | 12 ++++++++++-- > > > 1 file changed, 10 insertions(+), 2 deletions(-) > > > > Should this go to the stable kernel trees as well? > > It's been there for a while. Introduced in 5fe2123647c1508 "OMAP/serial: > Support 1Mbaud and similar baudrates that require Mode16 instead of > Mode13" (v3.9). It's probably a good idea to do so. stable@... needs a > cc? And would it be enough to just resend this particular patch in that case? -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/tty/serial/omap-serial.c b/drivers/tty/serial/omap-serial.c index d017cec..e454b7c 100644 --- a/drivers/tty/serial/omap-serial.c +++ b/drivers/tty/serial/omap-serial.c @@ -254,8 +254,16 @@ serial_omap_baud_is_mode16(struct uart_port *port, unsigned int baud) { unsigned int n13 = port->uartclk / (13 * baud); unsigned int n16 = port->uartclk / (16 * baud); - int baudAbsDiff13 = baud - (port->uartclk / (13 * n13)); - int baudAbsDiff16 = baud - (port->uartclk / (16 * n16)); + int baudAbsDiff13; + int baudAbsDiff16; + + if (n13 == 0) + n13 = 1; + if (n16 == 0) + n16 = 1; + + baudAbsDiff13 = baud - (port->uartclk / (13 * n13)); + baudAbsDiff16 = baud - (port->uartclk / (16 * n16)); if (baudAbsDiff13 < 0) baudAbsDiff13 = -baudAbsDiff13; if (baudAbsDiff16 < 0)
If the chosen baud rate is large enough (e.g. 3.5 megabaud), the calculated n values in serial_omap_is_baud_mode16() may become 0. This causes a division by zero when calculating the difference between calculated and desired baud rates. To prevent this, cap the n13 and n16 values on 1. Division by zero in kernel. [<c00132e0>] (unwind_backtrace) from [<c00112ec>] (show_stack+0x10/0x14) [<c00112ec>] (show_stack) from [<c01ed7bc>] (Ldiv0+0x8/0x10) [<c01ed7bc>] (Ldiv0) from [<c023805c>] (serial_omap_baud_is_mode16+0x4c/0x68) [<c023805c>] (serial_omap_baud_is_mode16) from [<c02396b4>] (serial_omap_set_termios+0x90/0x8d8) [<c02396b4>] (serial_omap_set_termios) from [<c0230a0c>] (uart_change_speed+0xa4/0xa8) [<c0230a0c>] (uart_change_speed) from [<c0231798>] (uart_set_termios+0xa0/0x1fc) [<c0231798>] (uart_set_termios) from [<c022bb44>] (tty_set_termios+0x248/0x2c0) [<c022bb44>] (tty_set_termios) from [<c022c17c>] (set_termios+0x248/0x29c) [<c022c17c>] (set_termios) from [<c022c3e4>] (tty_mode_ioctl+0x1c8/0x4e8) [<c022c3e4>] (tty_mode_ioctl) from [<c0227e70>] (tty_ioctl+0xa94/0xb18) [<c0227e70>] (tty_ioctl) from [<c00cf45c>] (do_vfs_ioctl+0x4a0/0x560) [<c00cf45c>] (do_vfs_ioctl) from [<c00cf568>] (SyS_ioctl+0x4c/0x74) [<c00cf568>] (SyS_ioctl) from [<c000e480>] (ret_fast_syscall+0x0/0x30) Signed-off-by: Frans Klaver <frans.klaver@xsens.com> --- drivers/tty/serial/omap-serial.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-)