Messages in this thread | | | Date | Wed, 12 Feb 2020 09:25:39 -0500 | From | Steven Rostedt <> | Subject | Re: [PATCH 5/8] x86,tracing: Mark debug_stack_{set_zero,reset)() notrace |
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On Wed, 12 Feb 2020 10:32:15 +0100 Peter Zijlstra <peterz@infradead.org> wrote:
> Because do_nmi() must not call into tracing outside of > nmi_enter()/nmi_exit(), these functions must be notrace. > > Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> > --- > arch/x86/kernel/cpu/common.c | 4 ++-- > arch/x86/kernel/nmi.c | 6 ++++++ > 2 files changed, 8 insertions(+), 2 deletions(-) > > --- a/arch/x86/kernel/cpu/common.c > +++ b/arch/x86/kernel/cpu/common.c
This entire file is notrace:
arch/x86/kernel/cpu/Makefile:
CFLAGS_REMOVE_common.o = -pg
-- Steve
> @@ -1690,14 +1690,14 @@ void syscall_init(void) > DEFINE_PER_CPU(int, debug_stack_usage); > DEFINE_PER_CPU(u32, debug_idt_ctr); > > -void debug_stack_set_zero(void) > +void notrace debug_stack_set_zero(void) > { > this_cpu_inc(debug_idt_ctr); > load_current_idt(); > } > NOKPROBE_SYMBOL(debug_stack_set_zero); > > -void debug_stack_reset(void) > +void notrace debug_stack_reset(void) > { > if (WARN_ON(!this_cpu_read(debug_idt_ctr))) > return; > --- a/arch/x86/kernel/nmi.c > +++ b/arch/x86/kernel/nmi.c > @@ -534,6 +534,9 @@ do_nmi(struct pt_regs *regs, long error_ > } > #endif > > + /* > + * It is important that no tracing happens before nmi_enter()! > + */ > nmi_enter(); > > inc_irq_stat(__nmi_count); > @@ -542,6 +545,9 @@ do_nmi(struct pt_regs *regs, long error_ > default_do_nmi(regs); > > nmi_exit(); > + /* > + * No tracing after nmi_exit()! > + */ > > #ifdef CONFIG_X86_64 > if (unlikely(this_cpu_read(update_debug_stack))) { >
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