linux-kernel - Re: [PATCH v2] scripts: Create objdump-func helper script

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Message-ID: <Yl8SaZbqXPJQyoXB@zn.tnic>
Date:   Tue, 19 Apr 2022 21:50:01 +0200
From:   Borislav Petkov <bp@...en8.de>
To:     Josh Poimboeuf <jpoimboe@...hat.com>
Cc:     Peter Zijlstra <peterz@...radead.org>,
        linux-kernel@...r.kernel.org, x86@...nel.org,
        Miroslav Benes <mbenes@...e.cz>
Subject: Re: [PATCH v2] scripts: Create objdump-func helper script

On Tue, Apr 19, 2022 at 09:12:23AM -0700, Josh Poimboeuf wrote:
> Add a simple script which disassembles a single function from an object
> file.  Comes in handy for objtool warnings and kernel stack traces.
> 
> Originally-by: Peter Zijlstra <peterz@...radead.org>
> Signed-off-by: Josh Poimboeuf <jpoimboe@...hat.com>
> ---
> v2:
> - require gawk
> 
>  scripts/objdump-func | 18 ++++++++++++++++++
>  1 file changed, 18 insertions(+)
>  create mode 100755 scripts/objdump-func

Was that supposed to be user-friendly too?

$ ./scripts/objdump-func -h
./scripts/objdump-func: line 16: $1: unbound variable

:-)


It works tho:

$ ./scripts/objdump-func vmlinux rewind_stack_and_make_dead
0000 ffffffff81001c00 <rewind_stack_and_make_dead>:
0000 ffffffff81001c00:  31 ed                   xor    %ebp,%ebp
0000 ffffffff81001c02:  65 48 8b 04 25 d0 ec 01 00      mov    %gs:0x1ecd0,%rax
0000 ffffffff81001c0b:  48 8d a0 58 ff ff ff    lea    -0xa8(%rax),%rsp
0000 ffffffff81001c12:  e8 39 24 07 00          call   ffffffff81074050 <make_task_dead>
^^^^

I guess those zeros at the beginning are supposed to mean something...

Thx.

-- 
Regards/Gruss,
    Boris.

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