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Message-ID: <mhng-95994d12-e1d9-43b3-bef0-c5c844ffcf86@palmerdabbelt-glaptop>
Date: Tue, 26 Oct 2021 16:48:10 -0700 (PDT)
From: Palmer Dabbelt <palmer@...belt.com>
To: yun.wang@...ux.alibaba.com
CC: guoren@...nel.org, rostedt@...dmis.org, mingo@...hat.com,
James.Bottomley@...senPartnership.com, deller@....de,
mpe@...erman.id.au, benh@...nel.crashing.org, paulus@...ba.org,
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aou@...s.berkeley.edu, tglx@...utronix.de, bp@...en8.de,
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mhiramat@...nel.org, peterz@...radead.org, npiggin@...il.com,
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live-patching@...r.kernel.org
Subject: Re: [PATCH 0/2] ftrace: make sure preemption disabled on recursion testing
On Mon, 11 Oct 2021 22:39:16 PDT (-0700), yun.wang@...ux.alibaba.com wrote:
> The testing show that perf_ftrace_function_call() are using
> smp_processor_id() with preemption enabled, all the checking
> on CPU could be wrong after preemption, PATCH 1/2 will fix
> that.
>
> Besides, as Peter point out, the testing of recursion within
> the section between ftrace_test_recursion_trylock()/_unlock()
> pair also need the preemption disabled as the documentation
> explained, PATCH 2/2 will make sure on that.
>
> Michael Wang (2):
> ftrace: disable preemption on the testing of recursion
> ftrace: prevent preemption in perf_ftrace_function_call()
>
> arch/csky/kernel/probes/ftrace.c | 2 --
> arch/parisc/kernel/ftrace.c | 2 --
> arch/powerpc/kernel/kprobes-ftrace.c | 2 --
> arch/riscv/kernel/probes/ftrace.c | 2 --
> arch/x86/kernel/kprobes/ftrace.c | 2 --
> include/linux/trace_recursion.h | 10 +++++++++-
> kernel/livepatch/patch.c | 6 ------
> kernel/trace/trace_event_perf.c | 17 +++++++++++++----
> kernel/trace/trace_functions.c | 5 -----
> 9 files changed, 22 insertions(+), 26 deletions(-)
Acked-by: Palmer Dabbelt <palmerdabbelt@...gle.com> # RISC-V
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