From: Peter Zijlstra peterz@infradead.org
[ Upstream commit 698bacefe993ad2922c9d3b1380591ad489355e9 ]
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 Signed-off-by: Sasha Levin sashal@kernel.org --- kernel/static_call.c | 14 ++++---------- 1 file changed, 4 insertions(+), 10 deletions(-)
diff --git a/kernel/static_call.c b/kernel/static_call.c index 84565c2a41b8..781ff0fd031d 100644 --- a/kernel/static_call.c +++ b/kernel/static_call.c @@ -144,6 +144,7 @@ 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) { @@ -163,6 +164,7 @@ 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
@@ -170,16 +172,8 @@ 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",