From: Peter Zijlstra peterz@infradead.org
mainline inclusion from mainline-v5.11-rc1 commit 55d2eba8e7cd439c11cdb204898c2d384227629b category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I61CQ3
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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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.... Signed-off-by: Wang ShaoBo bobo.shaobowang@huawei.com Reviewed-by: Xie XiuQi xiexiuqi@huawei.com Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com --- kernel/jump_label.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/kernel/jump_label.c b/kernel/jump_label.c index 7470cdc432a0..600dbdab24e7 100644 --- a/kernel/jump_label.c +++ b/kernel/jump_label.c @@ -823,6 +823,7 @@ int jump_label_text_reserved(void *start, void *end) static void jump_label_update(struct static_key *key) { struct jump_entry *stop = __stop___jump_table; + bool init = system_state < SYSTEM_RUNNING; struct jump_entry *entry; #ifdef CONFIG_MODULES struct module *mod; @@ -834,15 +835,16 @@ static void jump_label_update(struct static_key *key)
preempt_disable(); mod = __module_address((unsigned long)key); - if (mod) + if (mod) { stop = mod->jump_entries + mod->num_jump_entries; + init = mod->state == MODULE_STATE_COMING; + } preempt_enable(); #endif entry = static_key_entries(key); /* if there are no users, entry can be NULL */ if (entry) - __jump_label_update(key, entry, stop, - system_state < SYSTEM_RUNNING); + __jump_label_update(key, entry, stop, init); }
#ifdef CONFIG_STATIC_KEYS_SELFTEST