From: Steven Rostedt <rostedt@goodmis.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org,
mingo@kernel.org, joel@joelfernandes.org,
gregkh@linuxfoundation.org, gustavo@embeddedor.com,
tglx@linutronix.de, paulmck@kernel.org, josh@joshtriplett.org,
mathieu.desnoyers@efficios.com, jiangshanlai@gmail.com
Subject: Re: [PATCH 5/8] x86,tracing: Mark debug_stack_{set_zero,reset)() notrace
Date: Wed, 12 Feb 2020 09:25:39 -0500 [thread overview]
Message-ID: <20200212092539.135934e1@gandalf.local.home> (raw)
In-Reply-To: <20200212094107.894657838@infradead.org>
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))) {
>
next prev parent reply other threads:[~2020-02-12 14:25 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-12 9:32 [PATCH 0/8] tracing vs rcu vs nmi Peter Zijlstra
2020-02-12 9:32 ` [PATCH 1/8] rcu: Rename rcu_irq_{enter,exit}_irqson() Peter Zijlstra
2020-02-12 9:32 ` [PATCH 2/8] rcu: Mark rcu_dynticks_curr_cpu_in_eqs() inline Peter Zijlstra
2020-02-12 9:32 ` [PATCH 3/8] rcu,tracing: Create trace_rcu_{enter,exit}() Peter Zijlstra
2020-02-12 9:32 ` [PATCH 4/8] sched,rcu,tracing: Mark preempt_count_{add,sub}() notrace Peter Zijlstra
2020-02-12 14:24 ` Steven Rostedt
2020-02-12 15:02 ` Peter Zijlstra
2020-02-12 15:14 ` Steven Rostedt
2020-02-12 15:38 ` Peter Zijlstra
2020-02-12 9:32 ` [PATCH 5/8] x86,tracing: Mark debug_stack_{set_zero,reset)() notrace Peter Zijlstra
2020-02-12 14:25 ` Steven Rostedt [this message]
2020-02-12 15:04 ` Peter Zijlstra
2020-02-12 15:18 ` Steven Rostedt
2020-02-12 15:39 ` Peter Zijlstra
2020-02-12 9:32 ` [PATCH 6/8] perf,tracing: Prepare the perf-trace interface for RCU changes Peter Zijlstra
2020-02-12 14:26 ` Steven Rostedt
2020-02-12 15:07 ` Mathieu Desnoyers
2020-02-12 9:32 ` [PATCH 7/8] tracing: Employ trace_rcu_{enter,exit}() Peter Zijlstra
2020-02-12 9:32 ` [PATCH 8/8] tracing: Remove regular RCU context for _rcuidle tracepoints (again) Peter Zijlstra
2020-02-12 14:29 ` Steven Rostedt
2020-02-12 15:12 ` Peter Zijlstra
2020-02-12 10:01 ` [PATCH 0/8] tracing vs rcu vs nmi Peter Zijlstra
2020-02-12 10:56 ` Will Deacon
2020-02-12 11:58 ` Peter Zijlstra
2020-02-12 14:32 ` Steven Rostedt
2020-02-12 15:21 ` Peter Zijlstra
2020-02-12 10:03 ` Peter Zijlstra
2020-02-12 10:07 ` Peter Zijlstra
2020-02-12 10:09 ` Peter Zijlstra
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