Re: kern/53590: DTrace fbt_getargdesc() fails with "Unknown function"

[christos%zoulas.com@localhost (Christos Zoulas)]

On Sep 11,  2:55pm, gson%gson.org@localhost (Andreas Gustafsson) wrote:
-- Subject: Re: kern/53590: DTrace fbt_getargdesc() fails with "Unknown funct

| The following reply was made to PR kern/53590; it has been noted by GNATS.
| 
| From: Andreas Gustafsson <gson%gson.org@localhost>
| To: Patrick Welche <prlw1%cam.ac.uk@localhost>
| Cc: gnats-bugs%NetBSD.org@localhost
| Subject: Re: kern/53590: DTrace fbt_getargdesc() fails with "Unknown function"
| Date: Tue, 11 Sep 2018 17:50:35 +0300
| 
|  Patrick Welche wrote:
|  >  I see:
|  >  
|  >  quark# modload dtrace_fbt
|  >  quark#  dtrace -n 'fbt::vmem_alloc:entry { trace(args[0]); }'
|  >  dtrace: description 'fbt::vmem_alloc:entry ' matched 1 probe
|  >  CPU     ID                    FUNCTION:NAME
|  >    1  20290                 vmem_alloc:entry       -2132062368
|  >    1  20290                 vmem_alloc:entry       -2132060864
|  >    1  20290                 vmem_alloc:entry       -2132062368
|  >  ^C
|  >  
|  >  quark# uname -a
|  >  NetBSD quark 8.99.25 NetBSD 8.99.25 (QUARK) #254: Mon Sep 10 11:38:46 BST 2018  prlw1@quark:/usr/src/sys/arch/amd64/compile/QUARK amd64
|  
|  Thank you, this is helpful.
|  
|  I see you are using a custom kernel.  How does it differ from GENERIC
|  - for example, have you done something to enable debug symbols?

You need a fully modular kernel for dtrace to work, otherwise the ctf
tables overflow and you only get the bupkis symbol.

christos