On Thu, 14 Dec 2023 at 09:53, Steven Rostedt <rostedt@xxxxxxxxxxx> wrote:
>
> + /*
> + * For architectures that can not do cmpxchg() in NMI, or require
> + * disabling interrupts to do 64-bit cmpxchg(), do not allow them
> + * to record in NMI context.
> + */
> + if ((!IS_ENABLED(CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG) ||
> + (IS_ENABLED(CONFIG_X86_32) && !IS_ENABLED(CONFIG_X86_CMPXCHG64))) &&
> + unlikely(in_nmi())) {
> + return NULL;
> + }
Again, this is COMPLETE GARBAGE.
You're using "ARCH_HAVE_NMI_SAFE_CMPXCHG" to test something that just
isn't what it's about.
Having a NMI-safe cmpxchg does *not* mean that you actualyl have a
NMI-safe 64-bit version.
You can't test it that way.
Stop making random changes that just happen to work on the one machine
you tested it on.
Linus
