Re: kern/43611: kernel-trace (via ktruss) reports wrong parameter/result values

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

On Jul 15,  8:15pm, dholland-bugs%netbsd.org@localhost (David Holland) wrote:
-- Subject: Re: kern/43611: kernel-trace (via ktruss) reports wrong parameter

|  Mm, point. Maybe we ought to invent a new kind of tracing for this
|  purpose (since supervised execution was trendy in research for a while
|  and it's getting to the point of moving to production...)
|  
|  I'm not sure if it makes sense for that to be different from a
|  debugger interface or not.

We already support PT_SYSCALL, although it might be broken in current.
|  
|   >  |  (I'm not particularly clear on exactly what ktruss does that's
|   >  |  different from running kdump afterwards, but then I've never been
|   >  |  particularly clear on why ktruss is desirable relative to running
|   >  |  kdump afterwards, either.)
|   >  
|   >  Interactivity; you can watch processes that stop and wait for events
|   >  and see what they do as you supply the different events.
|  
|  Ah. Yeah, I guess that can be useful. The main problem I've always had
|  with strace and truss and whatnot is that the trace output gets mixed
|  with the program's output; when I first found ktrace years ago it was
|  a big step forward.

For that you can use -o fname and tail -f fname in another pty.

christos