Re: [PATCH] arm:traps: Don't print stack or raw PC/LR values in backtraces

[Xiaoming Ni]

On 2020/10/12 5:32, Russell King - ARM Linux admin wrote:
> On Fri, Oct 09, 2020 at 10:18:20AM +0200, Sebastian Andrzej Siewior wrote:
> > On 2020-10-09 09:08:50 [+0100], Russell King - ARM Linux admin wrote:
> > > I am really not happy about this - it hurts at least my ability to
> > > debug the kernel when people post oopses to the mailing list. If
> > > people wish to make the kernel harder to debug, and are prepared
> > > to be told "your kernel is undebuggable" then this patch is fine.
> >
> > I haven't look at the patch but don't they keep/add the representation:
> >    PC: symbol+offset/size
> >    LR: symbol+offset/size
> >
> > ? This is needed at very least as a replacement for the missing address.
>
> I don't have a problem getting rid of the hex numbers in [< >]
> although then I will need to convert the symbol back to an address
> using the vmlinux to then calculate its address to then find the
> appropriate place in the objdump output - because objdump does
> _not_ use the symbol+offset annotation.  Yes, I really do look up
> the numeric addresses in the objdump output to then read the
> disassembly.
>
> $ objdump -d vmlinux | less
>
> and then search for the address is the fastest and most convenient
> way for me rather than having to deal with some random script.
>
> Maybe I'm just antequated about how I do my debugging, but this
> seems to me to be the most efficient and fastest way.
The loading address of the kernel module is not fixed, so symbol+offset 
is more useful than a hexadecimal address when the call stack contains 
kernel module symbols.
Delete the PC/LR address and retain the sysbol+offset. The kernel can 
still be debugged.

Thanks
Xiaoming Ni