3.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> commit dc1dc2f8a5dd863bf2e79f338fc3ae29e99c683a upstream. When booting a multi-platform m68k kernel on a non-Mac with "console=ttyS0" on the kernel command line, it crashes with: Unable to handle kernel NULL pointer dereference at virtual address (null) Oops: 00000000 PC: [<0013ad28>] __pmz_startup+0x32/0x2a0 ... Call Trace: [<002c5d3e>] pmz_console_setup+0x64/0xe4 The normal tty driver doesn't crash, because init_pmz() checks pmz_ports_count again after calling pmz_probe(). In the serial console initialization path, pmz_console_init() doesn't do this, causing the driver to crash later. Add a check for pmz_ports_count to fix this. Signed-off-by: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> Cc: Finn Thain <fthain@xxxxxxxxxxxxxxxxxxx> Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/tty/serial/pmac_zilog.c | 3 +++ 1 file changed, 3 insertions(+) --- a/drivers/tty/serial/pmac_zilog.c +++ b/drivers/tty/serial/pmac_zilog.c @@ -2051,6 +2051,9 @@ static int __init pmz_console_init(void) /* Probe ports */ pmz_probe(); + if (pmz_ports_count == 0) + return -ENODEV; + /* TODO: Autoprobe console based on OF */ /* pmz_console.index = i; */ register_console(&pmz_console); -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html