ISC_PLATFORM_USEBACKTRACE

[Gary E. Miller]

Yo Hal!

On Tue, 30 May 2017 23:12:40 -0700
Hal Murray <hmurray at megapathdsl.net> wrote:

> Gary said:
> > There was never a way to decode the addresses beyond that.  Is that
> > any use? Any way to improve it so it has value?   
> 
> > #5 0x556b8bed9299 in ??  
> 
> I assume those are PCs.

Yes.

> Is there a way to get gdb to turn them into symbols?

Nope, not with gdb.

> Assuming I have
> the right ntpd handy.

Pretty unlikely you are running a binary different from the binary
you have in front of you.  :-)

> A while ago, you removed some symbol code.  Did that have any hope of 
> printing out something useful?

Nope.  The only way that worked was to hand code the symbol offset,
which nobody had ever done.

I did find this: backtrace_symbols(), which is gcc only.  It adds a bit
of decoding, assuming no stripping and some special LDFLAGS, but hardly
better.

So I wanted to see what backtrace() did with a seccomp fault, but now
I see that even though I have seccomp in my kernel, and compiled in, that
I can not trigger a seccomp fault, even if I remove syscalls that I
know ntpd uses...

RGDS
GARY
---------------------------------------------------------------------------
Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
	gem at rellim.com  Tel:+1 541 382 8588

	    Veritas liberabit vos. -- Quid est veritas?
    "If you can’t measure it, you can’t improve it." - Lord Kelvin
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