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Date:   Thu, 21 Oct 2021 20:52:22 -0700
From:   Andrew Morton <akpm@linux-foundation.org>
To:     Yafang Shao <laoar.shao@gmail.com>
Cc:     keescook@chromium.org, rostedt@goodmis.org,
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Subject: Re: [PATCH v5 00/15] extend task comm from 16 to 24 for
 CONFIG_BASE_FULL
Message-Id: <20211021205222.714a76c854cc0e7a7d6db890@linux-foundation.org>
In-Reply-To: <20211021034516.4400-1-laoar.shao@gmail.com>
References: <20211021034516.4400-1-laoar.shao@gmail.com>
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On Thu, 21 Oct 2021 03:45:07 +0000 Yafang Shao <laoar.shao@gmail.com> wrote:

> This patchset changes files among many subsystems. I don't know which
> tree it should be applied to, so I just base it on Linus's tree.

I can do that ;)

> There're many truncated kthreads in the kernel, which may make trouble
> for the user, for example, the user can't get detailed device
> information from the task comm.

That sucked of us.

> This patchset tries to improve this problem fundamentally by extending
> the task comm size from 16 to 24. In order to do that, we have to do
> some cleanups first.

It's at v5 and there's no evidence of review activity?  C'mon, folks!

> 1. Make the copy of task comm always safe no matter what the task
> comm size is. For example,
> 
>   Unsafe                 Safe
>   strlcpy                strscpy_pad
>   strncpy                strscpy_pad
>   bpf_probe_read_kernel  bpf_probe_read_kernel_str
>                          bpf_core_read_str
>                          bpf_get_current_comm
>                          perf_event__prepare_comm
>                          prctl(2)
> 
> 2. Replace the old hard-coded 16 with a new macro TASK_COMM_LEN_16 to
> make it more grepable.
> 
> 3. Extend the task comm size to 24 for CONFIG_BASE_FULL case and keep it
> as 16 for CONFIG_BASE_SMALL.

Is this justified?  How much simpler/more reliable/more maintainable/
would the code be if we were to make CONFIG_BASE_SMALL suffer with the
extra 8 bytes?

> 4. Print a warning if the kthread comm is still truncated.