Re: port-mips/52892: Tests hang on MIPS

[Andreas Gustafsson <gson%gson.org@localhost>]

The following reply was made to PR port-mips/52892; it has been noted by GNATS.

From: Andreas Gustafsson <gson%gson.org@localhost>
To: gnats-bugs%NetBSD.org@localhost
Cc: christos%NetBSD.org@localhost
Subject: Re: port-mips/52892: Tests hang on MIPS
Date: Thu, 19 Apr 2018 15:40:41 +0300

 I have now looked into this some more, and have the following
 observations:
 
 1. The tests are still hanging every time on b5:
 
   http://releng.netbsd.org/b5reports/hpcmips/
   http://releng.netbsd.org/b5reports/pmax/
 
 2. I can reliably reproduce the hang on hpcmips under gxemul
 by running
 
   cd /usr/tests/net/icmp
   while true; do atf-run t_ping|atf-report; done
 
 On b5, this usually hangs within an hour, but on my own test machine,
 it took a day or two to hang.
 
 3. It's the kernel that's hanging, not just ATF.  For example, if I
 run the above test script in the background with output redirected to
 a log file, and "tail -f" the log file on the console, I'm unable to
 kill the tail process using the interrupt character after the test has
 hung.
 
 4. By bisection, I found that the hpcmips tests started hanging on b5
 at the time of the commit
 
   2017.12.02.22.51.22 christos src/sys/kern/kern_lwp.c 1.191
 
 Since this caused the tests to hang earlier in the test run, in the
 lib/libc/sys/t_ptrace_wait3:resume1 test rather than in the network
 related tests where it is now hanging, it was not immediately clear
 whether that commit also triggered the present issue.  However...
 
 5. If I revert that commit, the tests do run to completion on b5.
 -- 
 Andreas Gustafsson, gson%gson.org@localhost