[ Upstream commit 1c41860864c8ae0387ef7d44f0000e99cbb2e06d ]

When doing unwind_frame() in the context of pseudo nmi (need enable
CONFIG_ARM64_PSEUDO_NMI), reaching the bottom of the stack (fp == 0,
pc != 0), function on_sdei_stack() will return true while the sdei acpi
table is not inited in fact. This will cause a "NULL pointer dereference"
oops when going on.
Reviewed-by: NJulien Thierry <julien.thierry@arm.com>
Signed-off-by: NWei Li <liwei391@huawei.com>
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NSasha Levin <sashal@kernel.org>