On Fri, Aug 21, 2020 at 10:36 AM Joe Perches <joe@xxxxxxxxxxx> wrote: > > On Thu, 2020-08-20 at 21:57 -0400, Steven Rostedt wrote: > > On Fri, 21 Aug 2020 09:39:19 +0800 > > Nicolas Boichat <drinkcat@xxxxxxxxxxxx> wrote: > [] > > > Some other approaches/ideas: > > > 1. Filter all lkml messages that contain trace_printk. Already found > > > 1 instance, and I can easily reply to those with a semi-canned answer, > > > if I remember to check that filter regularly (not sustainable in the > > > long run...). > > > > Added Joe Perches to the thread. > > > > We can update checkpatch.pl to complain about a trace_printk() that it > > finds in the added code. > > Why? > > I don't see much value in a trace_printk checkpatch warning. > tracing is still dependent on CONFIG_TRACING otherwise > trace_printk is an if (0) > > ELI5 please. This is my "new" canned answer to this: Please do not use trace_printk in production code [1,2], it is only meant for debug use. Consider using trace events, or dev_dbg. [1] https://elixir.bootlin.com/linux/v5.8/source/kernel/trace/trace.c#L3158 [2] https://elixir.bootlin.com/linux/v5.8/source/include/linux/kernel.h#L766 I also had arguments in patch 2/3 notes: There's at least 3 reasons that I can come up with: 1. trace_printk introduces some overhead. [some users, e.g. Android/Chrome OS, want CONFIG_TRACING but _not_ that extra overhead] 2. If the kernel keeps adding always-enabled trace_printk, it will be much harder for developers to make use of trace_printk for debugging. 3. People may assume that trace_printk is for debugging only, and may accidentally output sensitive data (theoretical at this stage). (we'll need to summarize that somehow if we want to add to checkpatch.pl)
