This is a note to let you know that I've just added the patch titled

    sunsu: Fix panic in case of nonexistent port at "console=ttySY" cmdline 
option

to the 3.4-stable tree which can be found at:
    
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     
sunsu-fix-panic-in-case-of-nonexistent-port-at-console-ttysy-cmdline-option.patch
and it can be found in the queue-3.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.


>From cef913bccdef37f6e3f2c3052614ebfc73609d48 Mon Sep 17 00:00:00 2001
From: Tkhai Kirill <[email protected]>
Date: Sat, 23 Feb 2013 23:01:15 +0000
Subject: sunsu: Fix panic in case of nonexistent port at "console=ttySY" 
cmdline option


From: Tkhai Kirill <[email protected]>

[ Upstream commit cb29529ea0030e60ef1bbbf8399a43d397a51526 ]

If a machine has X (X < 4) sunsu ports and cmdline
option "console=ttySY" is passed, where X < Y <= 4,
than the following panic happens:

Unable to handle kernel NULL pointer dereference
TPC: <sunsu_console_setup+0x78/0xe0>
RPC: <sunsu_console_setup+0x74/0xe0>
I7: <register_console+0x378/0x3e0>
Call Trace:
 [0000000000453a38] register_console+0x378/0x3e0
 [0000000000576fa0] uart_add_one_port+0x2e0/0x340
 [000000000057af40] su_probe+0x160/0x2e0
 [00000000005b8a4c] platform_drv_probe+0xc/0x20
 [00000000005b6c2c] driver_probe_device+0x12c/0x220
 [00000000005b6da8] __driver_attach+0x88/0xa0
 [00000000005b4df4] bus_for_each_dev+0x54/0xa0
 [00000000005b5a54] bus_add_driver+0x154/0x260
 [00000000005b7190] driver_register+0x50/0x180
 [00000000006d250c] sunsu_init+0x18c/0x1e0
 [00000000006c2668] do_one_initcall+0xe8/0x160
 [00000000006c282c] kernel_init_freeable+0x12c/0x1e0
 [0000000000603764] kernel_init+0x4/0x100
 [0000000000405f64] ret_from_syscall+0x1c/0x2c
 [0000000000000000]           (null)

1)Fix the panic;
2)Increment registered port number every successful
probe.

Signed-off-by: Kirill Tkhai <[email protected]>
CC: David Miller <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
 drivers/tty/serial/sunsu.c |   21 +++++++++------------
 1 file changed, 9 insertions(+), 12 deletions(-)

--- a/drivers/tty/serial/sunsu.c
+++ b/drivers/tty/serial/sunsu.c
@@ -968,6 +968,7 @@ static struct uart_ops sunsu_pops = {
 #define UART_NR        4
 
 static struct uart_sunsu_port sunsu_ports[UART_NR];
+static int nr_inst; /* Number of already registered ports */
 
 #ifdef CONFIG_SERIO
 
@@ -1337,13 +1338,8 @@ static int __init sunsu_console_setup(st
        printk("Console: ttyS%d (SU)\n",
               (sunsu_reg.minor - 64) + co->index);
 
-       /*
-        * Check whether an invalid uart number has been specified, and
-        * if so, search for the first available port that does have
-        * console support.
-        */
-       if (co->index >= UART_NR)
-               co->index = 0;
+       if (co->index > nr_inst)
+               return -ENODEV;
        port = &sunsu_ports[co->index].port;
 
        /*
@@ -1408,7 +1404,6 @@ static enum su_type __devinit su_get_typ
 
 static int __devinit su_probe(struct platform_device *op)
 {
-       static int inst;
        struct device_node *dp = op->dev.of_node;
        struct uart_sunsu_port *up;
        struct resource *rp;
@@ -1418,16 +1413,16 @@ static int __devinit su_probe(struct pla
 
        type = su_get_type(dp);
        if (type == SU_PORT_PORT) {
-               if (inst >= UART_NR)
+               if (nr_inst >= UART_NR)
                        return -EINVAL;
-               up = &sunsu_ports[inst];
+               up = &sunsu_ports[nr_inst];
        } else {
                up = kzalloc(sizeof(*up), GFP_KERNEL);
                if (!up)
                        return -ENOMEM;
        }
 
-       up->port.line = inst;
+       up->port.line = nr_inst;
 
        spin_lock_init(&up->port.lock);
 
@@ -1461,6 +1456,8 @@ static int __devinit su_probe(struct pla
                }
                dev_set_drvdata(&op->dev, up);
 
+               nr_inst++;
+
                return 0;
        }
 
@@ -1488,7 +1485,7 @@ static int __devinit su_probe(struct pla
 
        dev_set_drvdata(&op->dev, up);
 
-       inst++;
+       nr_inst++;
 
        return 0;
 


Patches currently in stable-queue which might be from [email protected] are

queue-3.4/sunsu-fix-panic-in-case-of-nonexistent-port-at-console-ttysy-cmdline-option.patch
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