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

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

The following reply was made to PR kern/53590; it has been noted by GNATS.

From: christos%zoulas.com@localhost (Christos Zoulas)
To: gnats-bugs%NetBSD.org@localhost, kern-bug-people%netbsd.org@localhost, 
	gnats-admin%netbsd.org@localhost, netbsd-bugs%netbsd.org@localhost, 
	gson%gson.org@localhost (Andreas Gustafsson)
Cc: 
Subject: Re: kern/53590: DTrace fbt_getargdesc() fails with "Unknown function"
Date: Tue, 11 Sep 2018 12:49:37 -0400

 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