From: Nicolas Boichat <drinkcat@xxxxxxxxxxxx> Subject: 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. Link: https://lkml.kernel.org/r/20200825193600.v2.1.I723c43c155f02f726c97501be77984f1e6bb740a@changeid Signed-off-by: Nicolas Boichat <drinkcat@xxxxxxxxxxxx> Cc: Steven Rostedt <rostedt@xxxxxxxxxxx> Cc: Joe Perches <joe@xxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- scripts/checkpatch.pl | 6 ++++++ 1 file changed, 6 insertions(+) --- a/scripts/checkpatch.pl~checkpatch-warn-if-trace_printk-and-friends-are-called +++ a/scripts/checkpatch.pl @@ -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. _
