ARM64: check stack pointer in get_wchan

get_wchan() is lockless. Task may wakeup at any time and change its own stack,
thus each next stack frame may be overwritten and filled with random stuff.

Signed-off-by: Konstantin Khlebnikov <k.khlebnikov@samsung.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Git-commit: 408c3658b0d49315974ce8b5aed385c8e1527595
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git


Signed-off-by: Ian Maund <imaund@codeaurora.org>