Re: kern/52117: ptrace(2) PTRACE_FORK fails on some platforms

[Martin Husemann <martin%duskware.de@localhost>]

The following reply was made to PR kern/52117; it has been noted by GNATS.

From: Martin Husemann <martin%duskware.de@localhost>
To: gnats-bugs%NetBSD.org@localhost
Cc: 
Subject: Re: kern/52117: ptrace(2) PTRACE_FORK fails on some platforms
Date: Tue, 28 Mar 2017 15:13:36 +0200

 On Tue, Mar 28, 2017 at 01:00:01PM +0000, Kamil Rytarowski wrote:
 >  Before calling wait4() for the child 19554
 >  Reported PTRACE_FORK event with forkee 11702
 >  Before calling wait4() for the forkee 11702 of the child 19554
 
 What happens here is (from my local run):
 
   5603      1 t_ptrace_wait4 GIO   fd 1 wrote 44 bytes
        "Reported PTRACE_FORK event with forkee 5251\n"
   5603      1 t_ptrace_wait4 RET   write 44/0x2c
   5603      1 t_ptrace_wait4 CALL  write(1,0xffffffffffffcbf8,0x3d)
   5603      1 t_ptrace_wait4 GIO   fd 1 wrote 61 bytes
        "Before calling wait4() for the forkee 5251 of the child 6264\n"
   5603      1 t_ptrace_wait4 RET   write 61/0x3d
   5603      1 t_ptrace_wait4 CALL  __wait450(0x1483,0xffffffffffffd240,0,0)
   5251      1 t_ptrace_wait4 EMUL  "netbsd"
   5251      1 t_ptrace_wait4 RET   fork 0
   5251      1 t_ptrace_wait4 CALL  exit(0xf)
   5603      1 t_ptrace_wait4 RET   __wait450 5251/0x1483
   5603      1 t_ptrace_wait4 CALL  writev(1,0xffffffffffffcc70,4)
   5603      1 t_ptrace_wait4 GIO   fd 1 wrote 75 bytes
        "failed: /ssd/src/tests/kernel/t_ptrace_wait.h:295: Reported exited pro\
         cess\n"
 
 Now note that wait4 is called on the childs forkee (5251) which does 
 nothing but exit. So WIFEXITED() is correct, but you probably want
 to wait for the child (6264) instead?
 
 Martin