x86, kaslr: fix module lock ordering problem
x86, kaslr: fix module lock ordering problem

There was a potential lock ordering problem with the module kASLR patch
("x86, kaslr: randomize module base load address"). This patch removes
the usage of the module_mutex and creates a new mutex to protect the
module base address offset value.

Chain exists of:
  text_mutex --> kprobe_insn_slots.mutex --> module_mutex

[    0.515561]  Possible unsafe locking scenario:
[    0.515561]
[    0.515561]        CPU0                    CPU1
[    0.515561]        ----                    ----
[    0.515561]   lock(module_mutex);
[    0.515561]                                lock(kprobe_insn_slots.mutex);
[    0.515561]                                lock(module_mutex);
[    0.515561]   lock(text_mutex);
[    0.515561]
[    0.515561]  *** DEADLOCK ***

Reported-by: Fengguang Wu <24f7fe9d205c8a9f6ade0c2894e14303ca16087f@intel.com>
Signed-off-by: Andy Honig <bcabda073ed7d87908c47c148553c19de226e7ab@google.com>
Signed-off-by: Kees Cook <50cb10d2be062154b17ab4d66a4eab34f1cf1c84@chromium.org>
Reviewed-by: Masami Hiramatsu <60fcdccfd958d359debfe6e6e7417cd7f1aaa9e3@hitachi.com>
Signed-off-by: H. Peter Anvin <8a453bad9912ffe59bc0f0b8abe03df9be19379e@linux.intel.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs