jump_label: Fix usage in module __init

When the static_key is part of the module, and the module calls
static_key_inc/enable() from it's __init section *AND* has a
static_branch_*() user in that very same __init section, things go
wobbly.

If the static_key lives outside the module, jump_label_add_module()
would append this module's sites to the key and jump_label_update()
would take the static_key_linked() branch and all would be fine.

If all the sites are outside of __init, then everything will be fine
too.

However, when all is aligned just as described above,
jump_label_update() calls __jump_label_update(.init = false) and we'll
not update sites in __init text.

Fixes: 19483677684b ("jump_label: Annotate entries that operate on __init code earlier")
Reported-by: Dexuan Cui <decui@microsoft.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Tested-by: Jessica Yu <jeyu@kernel.org>
Link: https://lkml.kernel.org/r/20201216135435.GV3092@hirez.programming.kicks-ass.net

+5 -3
+5 -3
kernel/jump_label.c
··· 793 793 static void jump_label_update(struct static_key *key) 794 794 { 795 795 struct jump_entry *stop = __stop___jump_table; 796 + bool init = system_state < SYSTEM_RUNNING; 796 797 struct jump_entry *entry; 797 798 #ifdef CONFIG_MODULES 798 799 struct module *mod; ··· 805 804 806 805 preempt_disable(); 807 806 mod = __module_address((unsigned long)key); 808 - if (mod) 807 + if (mod) { 809 808 stop = mod->jump_entries + mod->num_jump_entries; 809 + init = mod->state == MODULE_STATE_COMING; 810 + } 810 811 preempt_enable(); 811 812 #endif 812 813 entry = static_key_entries(key); 813 814 /* if there are no users, entry can be NULL */ 814 815 if (entry) 815 - __jump_label_update(key, entry, stop, 816 - system_state < SYSTEM_RUNNING); 816 + __jump_label_update(key, entry, stop, init); 817 817 } 818 818 819 819 #ifdef CONFIG_STATIC_KEYS_SELFTEST