Re: [PATCH v4 6/6] arm64: ftrace: add arch-specific stack tracer

From	Jungseok Lee <jungseoklee85@gmail.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH v4 6/6] arm64: ftrace: add arch-specific stack tracer
Date	2015-11-01 09:40 +0100
Message-ID	<qpWlc-5V0-3@gated-at.bofh.it> (permalink)
References	<qpaqe-1Jj-1@gated-at.bofh.it> <qpaqe-1Jj-3@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On Oct 30, 2015, at 2:25 PM, AKASHI Takahiro wrote:

Hi Akashi,

> Stack tracer on arm64, check_stack(), is uniqeue in the following
> points:
> * analyze a function prologue of a traced function to estimate a more
>  accurate stack pointer value, replacing naive '<child's fp> + 0x10.'
> * use walk_stackframe(), instead of slurping stack contents as orignal
>  check_stack() does, to identify a stack frame and a stack index (height)
>  for every callsite.
> 
> Regarding a function prologue analyzer, there is no guarantee that we can
> handle all the possible patterns of function prologue as gcc does not use
> any fixed templates to generate them. 'Instruction scheduling' is another
> issue here.
> Nevertheless, the current version will surely cover almost all the cases
> in the kernel image and give us useful information on stack pointers.

Can I get an idea on how to test the function prologue analyzer? It pretty
tough to compare stack trace data with objdump one. Is there an easier way
to observe this enhancement without objdump?

Best Regards
Jungseok Lee
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Thread

[PATCH v4 0/6] arm64: ftrace: fix incorrect output from stack tracer AKASHI Takahiro <takahiro.akashi@linaro.org> - 2015-10-30 06:30 +0100
  [PATCH v4 5/6] arm64: insn: add instruction decoders for ldp/stp and add/sub AKASHI Takahiro <takahiro.akashi@linaro.org> - 2015-10-30 06:30 +0100
  [PATCH v4 1/6] arm64: ftrace: adjust callsite addresses examined by stack tracer AKASHI Takahiro <takahiro.akashi@linaro.org> - 2015-10-30 06:30 +0100
    Re: [PATCH v4 1/6] arm64: ftrace: adjust callsite addresses examined  by stack tracer Will Deacon <will.deacon@arm.com> - 2015-10-30 12:20 +0100
      Re: [PATCH v4 1/6] arm64: ftrace: adjust callsite addresses examined  by stack tracer Mark Rutland <mark.rutland@arm.com> - 2015-11-02 19:30 +0100
        Re: [PATCH v4 1/6] arm64: ftrace: adjust callsite addresses examined  by stack tracer Will Deacon <will.deacon@arm.com> - 2015-11-02 19:50 +0100
          Re: [PATCH v4 1/6] arm64: ftrace: adjust callsite addresses examined  by stack tracer Mark Rutland <mark.rutland@arm.com> - 2015-11-02 19:50 +0100
      Re: [PATCH v4 1/6] arm64: ftrace: adjust callsite addresses  examined by stack tracer Steven Rostedt <rostedt@goodmis.org> - 2015-11-02 19:30 +0100
  [PATCH v4 2/6] arm64: ftrace: modify a stack frame in a safe way AKASHI Takahiro <takahiro.akashi@linaro.org> - 2015-10-30 06:30 +0100
  [PATCH v4 4/6] ftrace: allow arch-specific stack tracer AKASHI Takahiro <takahiro.akashi@linaro.org> - 2015-10-30 06:30 +0100
  [PATCH v4 3/6] arm64: ftrace: fix a stack tracer's output under function graph tracer AKASHI Takahiro <takahiro.akashi@linaro.org> - 2015-10-30 06:30 +0100
    Re: [PATCH v4 3/6] arm64: ftrace: fix a stack tracer's output under function graph tracer Jungseok Lee <jungseoklee85@gmail.com> - 2015-11-01 09:10 +0100
      Re: [PATCH v4 3/6] arm64: ftrace: fix a stack tracer's output under  function graph tracer AKASHI Takahiro <takahiro.akashi@linaro.org> - 2015-11-04 09:00 +0100
  [PATCH v4 6/6] arm64: ftrace: add arch-specific stack tracer AKASHI Takahiro <takahiro.akashi@linaro.org> - 2015-10-30 06:30 +0100
    Re: [PATCH v4 6/6] arm64: ftrace: add arch-specific stack tracer Jungseok Lee <jungseoklee85@gmail.com> - 2015-11-01 09:40 +0100
      Re: [PATCH v4 6/6] arm64: ftrace: add arch-specific stack tracer AKASHI Takahiro <takahiro.akashi@linaro.org> - 2015-11-04 09:10 +0100
    Re: [PATCH v4 6/6] arm64: ftrace: add arch-specific stack tracer yalin wang <yalin.wang2010@gmail.com> - 2015-11-04 09:50 +0100

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