3.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Geert Uytterhoeven <ge...@linux-m68k.org>
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 <ge...@linux-m68k.org>
Cc: Finn Thain <fth...@telegraphics.com.au>
Cc: Benjamin Herrenschmidt <b...@kernel.crashing.org>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
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);
--
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