Messages in this thread | | | Date | Thu, 23 Mar 2023 14:42:20 -0400 | From | Steven Rostedt <> | Subject | Re: [PATCH] tracepoint: Fix CFI failures with tp_stub_func |
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On Thu, 23 Mar 2023 14:37:15 -0400 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> wrote:
> > Repeated again so Mathieu doesn't have to search for it. > > > > [ Note, this version does use undefined compiler behavior (assuming that > > a stub function with no parameters or return, can be called by a location > > that thinks it has parameters but still no return value. Static calls > > do the same thing, so this trick is not without precedent. > > > > There's another solution that uses RCU tricks and is more complex, but > > can be an alternative if this solution becomes an issue. > > > > Link: https://lore.kernel.org/lkml/20210127170721.58bce7cc@gandalf.local.home/ > > ] > > Ugh. The last thing we need there is more RCU complexity. My brain is still recovering > from fixing the last time the introduction of static calls special-cases ended up subtly > breaking tracepoints.
Well, we can go back to your approach with doing the check in the iterator. Setting it to 0x1UL I think is what you wanted (to know it's a removed function and not a random NULL).
I could write that up if you want.
-- Steve
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