MIPS: Fix kernel lockup or crash after CPU offline/online

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 <[email protected]>
Signed-off-by: Aaro Koskinen <[email protected]>
Cc: [email protected]
Cc: David Daney <[email protected]>
Cc: [email protected]
Cc: [email protected]
Patchwork: https://patchwork.linux-mips.org/patch/8953/
Signed-off-by: Ralf Baechle <[email protected]>

diff --git a/arch/mips/kernel/smp.c b/arch/mips/kernel/smp.c
index c94c4e92e17d4bb964a5ca8e7ae77523c4fa44a4..1c0d8c50b7e120482e7891c82653e49a5b63a953 100644 (file)
--- a/arch/mips/kernel/smp.c
+++ b/arch/mips/kernel/smp.c
@@ -123,10 +123,10 @@ 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