Messages in this thread | | | Date | Wed, 14 Feb 2018 12:01:12 -0500 | From | Steven Rostedt <> | Subject | Re: [PATCH 1/3] jump_label: Warn on failed jump_label patch |
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On Wed, 14 Feb 2018 10:40:41 -0600 Josh Poimboeuf <jpoimboe@redhat.com> wrote:
> 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.
I made ftrace function tracing work on init code, can we do the same with tracepoints (aka jump labels)?
But I have to say that this goes with my argument that there exists tracepoints in the kernel that nobody cares about ;-)
-- Steve
> > 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); > + } > } > } >
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