On Tue, 2020-08-25 at 15:09 +0800, Nicolas Boichat wrote:
> trace_printk is meant as a debugging tool, and should not be
> compiled into production code without specific debug Kconfig
> options enabled, or source code changes, as indicated by the
> warning that shows up on boot if any trace_printk is called:
> ** NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE **
> ** **
> ** trace_printk() being used. Allocating extra memory. **
> ** **
> ** This means that this is a DEBUG kernel and it is **
> ** unsafe for production use. **
>
> Let's warn developers when they try to submit such a change.
>
> Signed-off-by: Nicolas Boichat <drink...@chromium.org>
> ---
>
> See also extensive discussion under this thread:
> https://lkml.org/lkml/2020/8/20/244
>
> This seems to be the simplest way to try to reduce the number
> of trace_printk that make it into the kernel.
I don't have a real objection, just some nits.
> diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
[]
> @@ -4272,6 +4272,14 @@ sub process {
> "Prefer dev_$level(... to dev_printk(KERN_$orig,
> ...\n" . $herecurr);
> }
>
> +# trace_printk should not be used in production code.
> + if ($line =~ /\b(trace_printk|trace_puts|ftrace_vprintk)\s*\(/)
> {
> + my $func = $1;
> +
> + WARN("TRACE_PRINTK",
> + "Do not use $func() in production code (this can
> be ignored if built only behind a debug config option).\n" . $herecurr);
You don't need to do an assign, you could use $1 directly.
I think 'built only behind' could be "building only with'.
No periods before the newline either.
> + }
> +
> # ENOSYS means "bad syscall nr" and nothing else. This will have a small
> # number of false positives, but assembly files are not checked, so at
> # least the arch entry code will not trigger this warning.
