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From: SeongJae Park <sj@kernel.org>
To: Yousef Alhouseen <alhouseenyousef@gmail.com>
Cc: SeongJae Park <sj@kernel.org>,
	willy@infradead.org,
	jack@suse.cz,
	shikemeng@huaweicloud.com,
	linux-fsdevel@vger.kernel.org,
	linux-mm@kvack.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] tools/writeback: parse help before importing drgn
Date: Wed, 24 Jun 2026 17:27:52 -0700
Message-ID: <20260625002752.96325-1-sj@kernel.org>
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On Wed, 24 Jun 2026 14:35:14 +0200 Yousef Alhouseen <alhouseenyousef@gmail.com> wrote:

> wb_monitor.py imports drgn before argparse can handle "-h". That makes
> help fail on systems where drgn is not installed, even though the script
> does not need drgn to print usage text.

But...  How do you execute the drgn script on systems not having drgn?  I tried
to mimic the situation and reproduce the issue you are saying about, but what I
get is like below:

    $ sudo mv /usr/bin/drgn /usr/bin/drgn.bak
    $ drgn tools/writeback/wb_monitor.py
    -bash: /usr/bin/drgn: No such file or directory
    $ python tools/writeback/wb_monitor.py
    Traceback (most recent call last):
      File "/home/lkhack/linux/tools/writeback/wb_monitor.py", line 44, in <module>
        bdi_list                = prog['bdi_list']
                                  ^^^^
    NameError: name 'prog' is not defined


Thanks,
SJ

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