The following commit has been merged into the locking/urgent branch of tip:
Commit-ID: 38c93587375053c5b9ef093f4a5ea754538cba32
Gitweb: https://git.kernel.org/tip/38c93587375053c5b9ef093f4a5ea754538cba32
Author: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
AuthorDate: Thu, 18 Mar 2021 11:31:51 +01:00
Committer: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
CommitterDate: Fri, 19 Mar 2021 13:16:44 +01:00
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@xxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Acked-by: Jarkko Sakkinen <jarkko@xxxxxxxxxx>
Tested-by: Sumit Garg <sumit.garg@xxxxxxxxxx>
Link: https://lkml.kernel.org/r/20210318113610.739542434@xxxxxxxxxxxxx
---
kernel/jump_label.c | 8 ++++++++
kernel/static_call.c | 11 ++++++++++-
2 files changed, 18 insertions(+), 1 deletion(-)
diff --git a/kernel/jump_label.c b/kernel/jump_label.c
index c6a39d6..ba39fbb 100644
--- 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 fc22590..2c5950b 100644
--- 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;
}
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