Re: [PATCH 00/13] replace print_symbol() with printk()-s

[Petr Mladek]

On Fri 2018-01-05 21:23:34, Sergey Senozhatsky wrote:
> On (01/05/18 21:01), Sergey Senozhatsky wrote:
> [..]
> > but, print_symbol() is compiled out on !CONFIG_KALLSYMS systems. so,
> > basically, we compile out some of errors print outs; even more, on ia64
> > ia64_do_show_stack() does nothing when there is no CONFIG_KALLSYMS [all
> > ia64 defconfigs have KALLSYMS_ALL enabled]. printk(%pS), unlike
> > print_symbol(), is not compiled out and prints the function address
> > when symbolic name is not available. but, at a glance, print_symbol()
> > in most of the cases has printk(registers) next to it or before it, so
> > it doesn't look like we are introducing a regression here by switching
> > to printk(%pS).
> 
> well, if this is a problem, then we can have

I believe that this is not a problem. If it was, we would most likely
need to solve it in the existing printk(%pS) callers.

> but we still have tons printk(%pS) in the kernel and even print_ip_sym()
> (which is not compiled out on !CONFIG_KALLSYMS). so it seems to me that
> we can drop print_symbol()/__print_symbol() and switch to printk(%pS)
> after all.

Exactly.

BTW: print_symbol() looks weird to me because:

   + looks like a normal printk() but
   + only one format specifier (%s) is replaced
   + %s is used to print an address/pointer

IMHO, this is counter-intuitive and even error prone.
Also it makes people using crazy hacks like the one fixed
in 4th patch, see
https://lkml.kernel.org/r/20171211125025.2270-5-sergey.senozhatsky@xxxxxxxxx

Best Regards,
Petr