static_call: Fix static_call_update() sanity check

Sites that match init_section_contains() get marked as INIT. For
built-in code init_sections contains both __init and __exit text. OTOH
kernel_text_address() only explicitly includes __init text (and there
are no __exit text markers).

Match what jump_label already does and ignore the warning for INIT
sites. Also see the excellent changelog for commit: 8f35eaa5f2de
("jump_label: Don't warn on __exit jump entries")

Fixes: 9183c3f9ed710 ("static_call: Add inline static call infrastructure")
Reported-by: Sumit Garg <sumit.garg@linaro.org>
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/20210318113610.739542434@infradead.org

diff --git a/kernel/jump_label.c b/kernel/jump_label.c
index c6a39d662935e494decf97a6f09b3f5ebda4975b..ba39fbb1f8e7382c4b0bd7ffd785618574a8e270 100644 (file)
--- a/kernel/jump_label.c
+++ b/kernel/jump_label.c
@@ -407,6 +407,14 @@ static bool jump_label_can_update(struct jump_entry *entry, bool init)
                return false;
 
        if (!kernel_text_address(jump_entry_code(entry))) {
+               /*
+                * This skips patching built-in __exit, which
+                * is part of init_section_contains() but is
+                * not part of kernel_text_address().
+                *
+                * Skipping built-in __exit is fine since it
+                * will never be executed.
+                */
                WARN_ONCE(!jump_entry_is_init(entry),
                          "can't patch jump_label at %pS",
                          (void *)jump_entry_code(entry));

diff --git a/kernel/static_call.c b/kernel/static_call.c
index fc2259047be21058ea05e337e420637317ddca5d..2c5950b0b90ef16dee7e27e93dfa8d8a230df75a 100644 (file)
--- a/kernel/static_call.c
+++ b/kernel/static_call.c
@@ -181,7 +181,16 @@ void __static_call_update(struct static_call_key *key, void *tramp, void *func)
                                continue;
 
                        if (!kernel_text_address((unsigned long)site_addr)) {
-                               WARN_ONCE(1, "can't patch static call site at %pS",
+                               /*
+                                * This skips patching built-in __exit, which
+                                * is part of init_section_contains() but is
+                                * not part of kernel_text_address().
+                                *
+                                * Skipping built-in __exit is fine since it
+                                * will never be executed.
+                                */
+                               WARN_ONCE(!static_call_is_init(site),
+                                         "can't patch static call site at %pS",
                                          site_addr);
                                continue;
                        }