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Subject[PATCH 3.4 142/176] MIPS: Fix kernel lockup or crash after CPU offline/online
Date
From: Hemmo Nieminen <hemmo.nieminen@iki.fi>

3.4.107-rc1 review patch. If anyone has any objections, please let me know.

------------------


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@iki.fi>
Signed-off-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Cc: David Daney <david.daney@cavium.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/8953/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
[lizf: Backported to 3.4: adjust context]
Signed-off-by: Zefan Li <lizefan@huawei.com>
---
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 ba9376b..7c2c1af 100644
--- a/arch/mips/kernel/smp.c
+++ b/arch/mips/kernel/smp.c
@@ -105,10 +105,10 @@ asmlinkage __cpuinit void start_secondary(void)
if ((read_c0_tcbind() & TCBIND_CURTC) == 0)
#endif /* CONFIG_MIPS_MT_SMTC */
cpu_probe();
- cpu_report();
per_cpu_trap_init();
mips_clockevent_init();
mp_ops->init_secondary();
+ cpu_report();

/*
* XXX parity protection should be folded in here when it's converted
--
1.9.1


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