BugLink: https://bugs.launchpad.net/bugs/1848589

[ Upstream commit c5e5c48c ]

The function free_module in file kernel/module.c as follow:

void free_module(struct module *mod) {
	......
	module_arch_cleanup(mod);
	......
	module_arch_freeing_init(mod);
	......
}

Both module_arch_cleanup and module_arch_freeing_init function
would free the mod->arch.init_unw_table, which cause double free.

Here, set mod->arch.init_unw_table = NULL after remove the unwind
table to avoid double free.
Signed-off-by: chenzefeng <chenzefeng2@huawei.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Connor Kuehl <connor.kuehl@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>