Commit dc1dd184 authored by Josh Poimboeuf's avatar Josh Poimboeuf Committed by Ingo Molnar

jump_label: Warn on failed jump_label patching attempt

Currently when the jump label code encounters an address which isn't
recognized by kernel_text_address(), it just silently fails.

This can be dangerous because jump labels are used in a variety of
places, and are generally expected to work.  Convert the silent failure
to a warning.

This won't warn about attempted writes to tracepoints in __init code
after initmem has been freed, as those are already guarded by the
entry->code check.
Signed-off-by: default avatarJosh Poimboeuf <>
Acked-by: default avatarPeter Zijlstra <>
Cc: Borislav Petkov <>
Cc: Jason Baron <>
Cc: Linus Torvalds <>
Cc: Steven Rostedt <>
Cc: Thomas Gleixner <>
Link: default avatarIngo Molnar <>
parent 33352244
......@@ -367,12 +367,15 @@ static void __jump_label_update(struct static_key *key,
for (; (entry < stop) && (jump_entry_key(entry) == key); entry++) {
* entry->code set to 0 invalidates module init text sections
* kernel_text_address() verifies we are not in core kernel
* init code, see jump_label_invalidate_module_init().
* An entry->code of 0 indicates an entry which has been
* disabled because it was in an init text area.
if (entry->code && kernel_text_address(entry->code))
arch_jump_label_transform(entry, jump_label_type(entry));
if (entry->code) {
if (kernel_text_address(entry->code))
arch_jump_label_transform(entry, jump_label_type(entry));
WARN_ONCE(1, "can't patch jump_label at %pS", (void *)entry->code);
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