Commit 8020b253 authored Oct 15, 2020 by Nicolas Boichat Committed by Linus Torvalds Oct 16, 2020

checkpatch: warn if trace_printk and friends are called



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 <drinkcat@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Joe Perches <joe@perches.com>
Link: https://lkml.kernel.org/r/20200825193600.v2.1.I723c43c155f02f726c97501be77984f1e6bb740a@changeid


Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent ed4761f7

scripts/checkpatch.pl

+6 −0

Original line number	Diff line number	Diff line
		@@ -4274,6 +4274,12 @@ 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*\(/) {
		WARN("TRACE_PRINTK",
		"Do not use $1() in production code (this can be ignored if built only with a debug config option)\n" . $herecurr);
		}

		# 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.

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