This is a note to let you know that I have just added a patch titled
MIPS: Fix kernel lockup or crash after CPU offline/online
to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree
which can be found at:
http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.16.y-queue
This patch is scheduled to be released in version 3.16.7-ckt7.
If you, or anyone else, feels it should not be added to this tree, please
reply to this email.
For more information about the 3.16.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable
Thanks.
-Luis
------
>From a5ff5fd2a9a92431e99609f294fcd102bf4b2a58 Mon Sep 17 00:00:00 2001
From: Hemmo Nieminen <hemmo.nieminen@xxxxxx>
Date: Thu, 15 Jan 2015 23:01:59 +0200
Subject: MIPS: Fix kernel lockup or crash after CPU offline/online
commit c7754e75100ed5e3068ac5085747f2bfc386c8d6 upstream.
As printk() invocation can cause e.g. a TLB miss, printk() cannot be
called before the exception handlers have been properly initialized.
This can happen e.g. when netconsole has been loaded as a kernel module
and the TLB table has been cleared when a CPU was offline.
Call cpu_report() in start_secondary() only after the exception handlers
have been initialized to fix this.
Without the patch the kernel will randomly either lockup or crash
after a CPU is onlined and the console driver is a module.
Signed-off-by: Hemmo Nieminen <hemmo.nieminen@xxxxxx>
Signed-off-by: Aaro Koskinen <aaro.koskinen@xxxxxx>
Cc: David Daney <david.daney@xxxxxxxxxx>
Cc: linux-mips@xxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
Patchwork: https://patchwork.linux-mips.org/patch/8953/
Signed-off-by: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
Signed-off-by: Luis Henriques <luis.henriques@xxxxxxxxxxxxx>
---
arch/mips/kernel/smp.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/mips/kernel/smp.c b/arch/mips/kernel/smp.c
index 9bad52ede903..9bc3561b6901 100644
--- a/arch/mips/kernel/smp.c
+++ b/arch/mips/kernel/smp.c
@@ -101,10 +101,10 @@ asmlinkage void start_secondary(void)
unsigned int cpu;
cpu_probe();
- cpu_report();
per_cpu_trap_init(false);
mips_clockevent_init();
mp_ops->init_secondary();
+ cpu_report();
/*
* XXX parity protection should be folded in here when it's converted
--
2.1.4
