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authorPeter Zijlstra <peterz@infradead.org>2021-03-18 11:29:56 +0100
committerPeter Zijlstra <peterz@infradead.org>2021-03-19 13:16:44 +0100
commit698bacefe993ad2922c9d3b1380591ad489355e9 (patch)
treedb3411741a396904c002645ecbcfce546a29e4f4
parent68b1eddd421d2b16c6655eceb48918a1e896bbbc (diff)
downloadlinux-stericsson-698bacefe993ad2922c9d3b1380591ad489355e9.tar.gz
static_call: Align static_call_is_init() patching condition
The intent is to avoid writing init code after init (because the text might have been freed). The code is needlessly different between jump_label and static_call and not obviously correct. The existing code relies on the fact that the module loader clears the init layout, such that within_module_init() always fails, while jump_label relies on the module state which is more obvious and matches the kernel logic. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Jarkko Sakkinen <jarkko@kernel.org> Tested-by: Sumit Garg <sumit.garg@linaro.org> Link: https://lkml.kernel.org/r/20210318113610.636651340@infradead.org
-rw-r--r--kernel/static_call.c14
1 files changed, 4 insertions, 10 deletions
diff --git a/kernel/static_call.c b/kernel/static_call.c
index 080c8a9ddfaf..fc2259047be2 100644
--- a/kernel/static_call.c
+++ b/kernel/static_call.c
@@ -149,6 +149,7 @@ void __static_call_update(struct static_call_key *key, void *tramp, void *func)
};
for (site_mod = &first; site_mod; site_mod = site_mod->next) {
+ bool init = system_state < SYSTEM_RUNNING;
struct module *mod = site_mod->mod;
if (!site_mod->sites) {
@@ -168,6 +169,7 @@ void __static_call_update(struct static_call_key *key, void *tramp, void *func)
if (mod) {
stop = mod->static_call_sites +
mod->num_static_call_sites;
+ init = mod->state == MODULE_STATE_COMING;
}
#endif
@@ -175,16 +177,8 @@ void __static_call_update(struct static_call_key *key, void *tramp, void *func)
site < stop && static_call_key(site) == key; site++) {
void *site_addr = static_call_addr(site);
- if (static_call_is_init(site)) {
- /*
- * Don't write to call sites which were in
- * initmem and have since been freed.
- */
- if (!mod && system_state >= SYSTEM_RUNNING)
- continue;
- if (mod && !within_module_init((unsigned long)site_addr, mod))
- continue;
- }
+ if (!init && static_call_is_init(site))
+ continue;
if (!kernel_text_address((unsigned long)site_addr)) {
WARN_ONCE(1, "can't patch static call site at %pS",