[PATCH 3.14 20/83] powerpc: Fix Oops in rtas_stop_self()

Greg Kroah-Hartman
2014-05-11T19:56:33Z

From: Li Zhong <zhong@linux.vnet.ibm.com>

commit 4fb8d027dca0236c811272d342cf185569d91311 upstream.

commit 41dd03a9 may cause Oops in rtas_stop_self().

The reason is that the rtas_args was moved into stack space. For a box
with more that 4GB RAM, the stack could easily be outside 32bit range,
but RTAS is 32bit.

So the patch moves rtas_args away from stack by adding static before
it.

Signed-off-by: Li Zhong <zhong@linux.vnet.ibm.com>
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
arch/powerpc/platforms/pseries/hotplug-cpu.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

--- a/arch/powerpc/platforms/pseries/hotplug-cpu.c
+++ b/arch/powerpc/platforms/pseries/hotplug-cpu.c
@@ -88,13 +88,14 @@ void set_default_offline_state(int cpu)

static void rtas_stop_self(void)
{
- struct rtas_args args = {
- .token = cpu_to_be32(rtas_stop_self_token),
+ static struct rtas_args args = {
.nargs = 0,
.nret = 1,
.rets = &args.args[0],
};

+ args.token = cpu_to_be32(rtas_stop_self_token);
+
local_irq_disable();

BUG_ON(rtas_stop_self_token == RTAS_UNKNOWN_SERVICE);