On Tue, Jul 01, 2025 at 10:38:36AM -0700, Bill Wendling wrote:
> On Tue, Jul 1, 2025 at 9:27 AM Kees Cook <k...@kernel.org> wrote:
> > I have not had the time to minimize it, no.
I can try to extract this into a minimal reproducer next week if nothing
major crops up over the long weekend.
> OPTIMIZER_HIDE_VAR doesn't have a 'volatile' on it. Could that be it?
I tested
diff --git a/include/linux/compiler.h b/include/linux/compiler.h
index 6f04a1d8c720..eab208a9a6f4 100644
--- a/include/linux/compiler.h
+++ b/include/linux/compiler.h
@@ -160,7 +160,7 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int
val,
#ifndef OPTIMIZER_HIDE_VAR
/* Make the optimizer believe the variable can be manipulated arbitrarily. */
#define OPTIMIZER_HIDE_VAR(var)
\
- __asm__ ("" : "=r" (var) : "0" (var))
+ __asm__ volatile("" : "=r" (var) : "0" (var))
#endif
#define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __COUNTER__)
but that did not resolve the error.
Cheers,
Nathan
