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: Josh Poimboeuf <jpoimboe@redhat.com> Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: Borislav Petkov <bp@suse.de> Cc: Jason Baron <jbaron@akamai.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/de3a271c93807adb7ed48f4e946b4f9156617680.1519051220.git.jpoimboe@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
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@ -367,12 +367,15 @@ static void __jump_label_update(struct static_key *key,
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{
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for (; (entry < stop) && (jump_entry_key(entry) == key); entry++) {
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/*
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* entry->code set to 0 invalidates module init text sections
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* kernel_text_address() verifies we are not in core kernel
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* init code, see jump_label_invalidate_module_init().
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* An entry->code of 0 indicates an entry which has been
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* disabled because it was in an init text area.
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*/
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if (entry->code && kernel_text_address(entry->code))
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arch_jump_label_transform(entry, jump_label_type(entry));
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if (entry->code) {
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if (kernel_text_address(entry->code))
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arch_jump_label_transform(entry, jump_label_type(entry));
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else
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WARN_ONCE(1, "can't patch jump_label at %pS", (void *)entry->code);
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}
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}
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}
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