Hi Doug, On Tue, Apr 28, 2020 at 02:13:45PM -0700, Douglas Anderson wrote: > diff --git a/arch/arm64/kernel/debug-monitors.c b/arch/arm64/kernel/debug-monitors.c > index 48222a4760c2..59c353dfc8e9 100644 > --- a/arch/arm64/kernel/debug-monitors.c > +++ b/arch/arm64/kernel/debug-monitors.c > @@ -297,7 +297,7 @@ void unregister_kernel_break_hook(struct break_hook *hook) > unregister_debug_hook(&hook->node); > } > > -static int call_break_hook(struct pt_regs *regs, unsigned int esr) > +int call_break_hook(struct pt_regs *regs, unsigned int esr) > { > struct break_hook *hook; > struct list_head *list; > diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c > index cf402be5c573..a8173f0c1774 100644 > --- a/arch/arm64/kernel/traps.c > +++ b/arch/arm64/kernel/traps.c > @@ -1044,6 +1044,9 @@ int __init early_brk64(unsigned long addr, unsigned int esr, > if ((comment & ~KASAN_BRK_MASK) == KASAN_BRK_IMM) > return kasan_handler(regs, esr) != DBG_HOOK_HANDLED; > #endif > + if (call_break_hook(regs, esr) == DBG_HOOK_HANDLED) > + return 0; I think this just means we're not running debug_traps_init() early enough, and actually the KASAN early handler is unnecessary too. If we call debug_traps_init() directly from setup_arch() and drop the arch_initcall(), can we then drop early_brk64 entirely? Will