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Subject[PATCH 1/3] jump_label: Warn on failed jump_label patch
Date
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.

Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
---
kernel/jump_label.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/kernel/jump_label.c b/kernel/jump_label.c
index b4517095db6a..c71fb7cdfc41 100644
--- a/kernel/jump_label.c
+++ b/kernel/jump_label.c
@@ -370,8 +370,12 @@ static void __jump_label_update(struct static_key *key,
* kernel_text_address() verifies we are not in core kernel
* init code, see jump_label_invalidate_module_init().
*/
- 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));
+ else
+ WARN_ONCE(1, "can't patch jump_label at %pS", (void *)entry->code);
+ }
}
}

--
2.14.3
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