Revert "rename open_issues.mdwn to service_solahart_jakarta_selatan__082122541663.mdwn"

This reverts commit 95878586ec7611791f4001a4ee17abf943fae3c1.

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+[[!meta copyright="Copyright © 2009, 2010, 2011, 2013, 2014 Free Software
+Foundation, Inc."]]
+
+[[!meta license="""[[!toggle id="license" text="GFDL 1.2+"]][[!toggleable
+id="license" text="Permission is granted to copy, distribute and/or modify this
+document under the terms of the GNU Free Documentation License, Version 1.2 or
+any later version published by the Free Software Foundation; with no Invariant
+Sections, no Front-Cover Texts, and no Back-Cover Texts.  A copy of the license
+is included in the section entitled [[GNU Free Documentation
+License|/fdl]]."]]"""]]
+
+[[!tag open_issue_hurd]]
+
+Given an `a.out` executable that only does `raise (SIGABRT)`, invoking that
+one...
+
+  * ... against `crash-dump-core` will...
+
+      * ... not overwrite existing `core` files.
+
+        Is this reasonable?  Linux does overwrite them, for example.
+
+      * ... show big variances in running-time behavior:
+
+            $ TIMEFORMAT='real %R user %U system %S'
+            $ rm -f core; time env CRASHSERVER=/servers/crash-dump-core ./a.out; ls -l core
+            Aborted (core dumped)
+            real 1.350 user 0.000 system 0.010
+            -rw------- 1 tschwinge tschwinge 17031168 Jul  7 21:59 core
+            $ rm -f core; time env CRASHSERVER=/servers/crash-dump-core ./a.out; ls -l core
+            Aborted (core dumped)
+            real 22.771 user 0.000 system 0.010
+            -rw------- 1 tschwinge tschwinge 17031168 Jul  7 21:59 core
+            $ rm -f core; time env CRASHSERVER=/servers/crash-dump-core ./a.out; ls -l core
+            Aborted (core dumped)
+            real 1.367 user 0.000 system 0.010
+            -rw------- 1 tschwinge tschwinge 17031168 Jul  7 22:00 core
+            $ rm -f core; time env CRASHSERVER=/servers/crash-dump-core ./a.out; ls -l core
+            Aborted (core dumped)
+            real 5.789 user 0.000 system 0.010
+            -rw------- 1 tschwinge tschwinge 17031168 Jul  7 22:00 core
+            $ rm -f core; time env CRASHSERVER=/servers/crash-dump-core ./a.out; ls -l core
+            Aborted (core dumped)
+            real 22.664 user 0.010 system 0.000
+            -rw------- 1 tschwinge tschwinge 17031168 Jul  7 22:01 core
+
+      * ... produce a huge `core` file:
+
+            $ du -hs core 
+            17M     core
+
+        On Linux, the `core` file occupies 76 KiB of disk space, which seems
+        much more reasonable. This is possibly related with the default 128MiB
+        heap preallocation.
+
+      * ... does not always produce a useful backtrace:
+
+        `abort();`
+
+            $ gdb test core
+            warning: core file may not match specified executable file.
+            [New Thread 86678]
+            warning: Wrong size fpregset in core file.
+            ...
+            Core was generated by `./test'.
+            Program terminated with signal 6, Aborted.
+            warning: Wrong size fpregset in core file.
+            (gdb) bt
+            #0  0x00000000 in ?? ()
+            #1  0x011f593f in __msg_sig_post (process=72, signal=6, sigcode=0, refport=1)
+                at /build/buildd-eglibc_2.10.2-7-hurd-i386-iGL6op/eglibc-2.10.2/build-tree/hurd-i386-libc/hurd/RPC_msg_sig_post.c:144
+            #2  0x0109a433 in kill_port (pid=<value optimized out>)
+                at ../sysdeps/mach/hurd/kill.c:68
+            #3  kill_pid (pid=<value optimized out>) at ../sysdeps/mach/hurd/kill.c:105
+            #4  0x0109a69f in __kill (pid=21142, sig=6) at ../sysdeps/mach/hurd/kill.c:139
+            #5  0x01099af6 in raise (sig=6) at ../sysdeps/posix/raise.c:27
+            #6  0x0109de59 in abort () at abort.c:88
+            #7  0x0804849f in main ()
+
+        `char *foo = 0; *foo = 1;`
+
+            $ gdb test core
+            Program terminated with signal 11, Segmentation fault.
+            warning: Wrong size fpregset in core file.
+            #0  0x00000000 in ?? ()
+            (gdb) bt
+            #0  0x00000000 in ?? ()
+            #1  0x0108565b in __libc_start_main (main=0x8048464 <main>, argc=1, ubp_av=0x1023e64, 
+                init=0x8048490 <__libc_csu_init>, fini=0x8048480 <__libc_csu_fini>, rtld_fini=0xea20 <_dl_fini>, 
+                stack_end=0x1023e5c) at libc-start.c:251
+            #2  0x080483d1 in _start ()
+
+        `raise (SIGABRT);`
+
+            $ gdb a.out core
+            warning: core file may not match specified executable file.
+            [New Thread 76651]
+            
+            warning: Wrong size fpregset in core file.
+            Reading symbols from /lib/libc.so.0.3...[...]
+            Core was generated by `./a.out'.
+            Program terminated with signal 6, Aborted.
+            
+            warning: Wrong size fpregset in core file.
+            #0  0x00000000 in ?? ()
+            (gdb) bt
+            #0  0x00000000 in ?? ()
+            Cannot access memory at address 0x17
+
+        [[!tag open_issue_gdb]] Probably [[GDB]] doesn't manage to dig in the stack properly.
+
+  * ... against `crash-suspend` will...
+
+      * ... not work at all:
+    
+            $ CRASHSERVER=/servers/crash-suspend ./a.out
+            $ [returns to the shell and doesn't suspended]
+
+      * ... show big variances in running-time behavior:
+    
+            $ TIMEFORMAT='real %R user %U system %S'
+            $ rm -f core; time env CRASHSERVER=/servers/crash-suspend ./a.out; ls -l core
+            Aborted (core dumped)
+            real 1.381 user 0.000 system 0.010
+            -rw------- 1 tschwinge tschwinge 17031168 Jul  7 22:04 core
+            $ rm -f core; time env CRASHSERVER=/servers/crash-suspend ./a.out; ls -l core
+            Aborted (core dumped)
+            real 1.332 user 0.000 system 0.010
+            -rw------- 1 tschwinge tschwinge 17031168 Jul  7 22:04 core
+            $ rm -f core; time env CRASHSERVER=/servers/crash-suspend ./a.out; ls -l core
+            Aborted (core dumped)
+            real 21.228 user 0.000 system 0.010
+            -rw------- 1 tschwinge tschwinge 17031168 Jul  7 22:04 core
+            $ rm -f core; time env CRASHSERVER=/servers/crash-suspend ./a.out; ls -l core
+            Aborted (core dumped)
+            real 1.323 user 0.000 system 0.010
+            -rw------- 1 tschwinge tschwinge 17031168 Jul  7 22:05 core
+            $ rm -f core; time env CRASHSERVER=/servers/crash-suspend ./a.out; ls -l core
+            Aborted (core dumped)
+            real 22.279 user 0.000 system 0.010
+            -rw------- 1 tschwinge tschwinge 17031168 Jul  7 22:05 core
+            $ rm -f core; time env CRASHSERVER=/servers/crash-suspend ./a.out; ls -l core
+            Aborted (core dumped)
+            real 1.362 user 0.000 system 0.000
+            -rw------- 1 tschwinge tschwinge 17031168 Jul  7 22:08 core
+            $ rm -f core; time env CRASHSERVER=/servers/crash-suspend ./a.out; ls -l core
+            Aborted (core dumped)
+            real 21.110 user 0.000 system 0.000
+            -rw------- 1 tschwinge tschwinge 17031168 Jul  7 22:08 core
+            $ rm -f core; time env CRASHSERVER=/servers/crash-suspend ./a.out; ls -l core
+            Aborted (core dumped)
+            real 1.350 user 0.000 system 0.020
+            -rw------- 1 tschwinge tschwinge 17031168 Jul  7 22:08 core
+
+      * ... can reliably crash GNU Mach:
+
+        This happens if a `core` file is already present (and won't get
+        overwritten; see above).  I reproduced this three times.
+
+            $ TIMEFORMAT='real %R user %U system %S'
+            $ time env CRASHSERVER=/servers/crash-suspend ./a.out; ls -l core
+            Aborted
+            real 2.856 user 0.000 system 0.010
+            -rw------- 1 tschwinge tschwinge 17031168 Jul  7 22:08 core
+
+            panic: zalloc: zone kalloc.8192 exhausted
+            Kernel Breakpoint trap, eip 0x20020a77
+            Stopped at  0x20020a76: int     $3
+            db> trace
+            0x20020a76(2006aba8,4d0f7e9c,200209b0,0,0)
+            0x20020a4d(2006b094,2006ae40,2000,20016803,4a5f4114)
+            0x2002bca5(49a03564,1,0,9,1000)
+            0x20022f4c(2000,4a5f45d4,4a84879c,49a46564,4ac43e78)
+            0x20021e65(4ac43e78,4a5f45d4,4a5f4114,0,0)
+            0x2005309d(2106ba9c,3,38,28,1783)
+            Bad frame pointer: 0x2106ba78
+
+            $ addr2line -i -f -e /boot/gnumach-xen 0x20020a76 0x20020a4d 0x2002bca5 0x20022f4c 0x20021e65 0x2005309d
+            Debugger
+            /home/tschwinge/tmp/gnumach/gnumach-1-branch-Xen-branch.build/../gnumach-1-branch-Xen-branch/kern/debug.c:105
+            panic
+            /home/tschwinge/tmp/gnumach/gnumach-1-branch-Xen-branch.build/../gnumach-1-branch-Xen-branch/kern/debug.c:148
+            zalloc
+            /home/tschwinge/tmp/gnumach/gnumach-1-branch-Xen-branch.build/../gnumach-1-branch-Xen-branch/kern/zalloc.c:470
+            kalloc
+            /home/tschwinge/tmp/gnumach/gnumach-1-branch-Xen-branch.build/../gnumach-1-branch-Xen-branch/kern/kalloc.c:185
+            ipc_kobject_server
+            /home/tschwinge/tmp/gnumach/gnumach-1-branch-Xen-branch.build/../gnumach-1-branch-Xen-branch/kern/ipc_kobject.c:76
+            mach_msg_trap
+            /home/tschwinge/tmp/gnumach/gnumach-1-branch-Xen-branch.build/../gnumach-1-branch-Xen-branch/ipc/mach_msg.c:1367
+
+
+# IRC, freenode, #hurd, 2013-09-07
+
+    <rekado> I'm trying to investigate a crash in pfinet, so it will actually
+      die.  I just want to know why it dies and what the value of a few
+      variables has been when it died.
+    <teythoon> have you tried to make it dump core?
+    <rekado> oh, good idea.
+    <rekado> I'll try that.
+    <teythoon> do you know how?
+    <rekado> I don't, but I think I can figure it out.
+    <teythoon> look into /servers
+    <rekado> do I just have to set CRASHSERVER=/servers/crash-dump-core and run
+      pfinet in that environment?
+    <teythoon> possibly, I've never heard of CRASHSERVER, but it's certainly
+      plausible ;)
+    <teythoon> I just link crash to crash-dump-core, that way it is permanent
+      and for all processes
+    <rekado> found it in the website contents
+    <rekado> gotta try that.
+    <rekado> hmm, I can't get pfinet to dump core; linked /servers/crash to
+      /servers/crash-dump-core and compiled pfinet to raise(6) at one point.
+    <rekado> But no core file is created.
+    <teythoon> :/
+    <teythoon> rekado: try cd /tmp ; cat & kill -SIGILL %% to see if that dumps
+      core
+    <rekado> yes, this works.
+    <rekado> I replaced the original pfinet with my crashing version.
+    <rekado> Should it dump core to /hurd then?
+    <teythoon> I'm not sure about it's wd
+    <teythoon> hm, ok, I just did settrans -ca foo /hurd/pfinet and then killed
+      that pfient with SIGILL and it dumped core
+    <teythoon> to the directory I issued the settrans from
+    <rekado> So I must run it myself.  I can't just replace the original binary
+      and have it dump core somewhere.
+    <teythoon> it seems that you have to use settrans -ca to start an active
+      translator
+    <teythoon> do fsysopts /servers/socket/2 to find out the cmdline of your
+      pfinet
+    <rekado> that's very helpful.
+    <rekado> thanks
+    <teythoon> then use this to restart it, e.g.:
+    <teythoon> settrans -afg /servers/socket/2 $(fsysopts /servers/socket/2)
+    <teythoon> if it dies it should dump core to you cwd
+    <rekado> great. Thank you very much.  I had been wondering how to get the
+      full cmdline of pfinet.
+    * rekado makes a note of fsysopts
+    <rekado> yup, there's the core file. Nice.
+    <teythoon> cool 8D
+    <teythoon> btw, in case using gdb doesn't work out for your problem, if you
+      start pfinet (or any translator) this way (with -a == active), you can
+      write stuff to stderr
+    <rekado> yeah, I noticed that.  The assert() call wrote to stderr.  Useful.
+    <braunr> rekado: core dumps are another not-working-well feature of the
+      hurd :/
+    <braunr> i recommend attaching
+    <tschwinge> rekado: In case that's still helpful:
+      <http://www.gnu.org/software/hurd/hurd/debugging/translator.html>.
+
+
+# IRC, freenode, #hurd, 2013-12-14
+
+    <gnu_srs> How to get a core dump?
+    <teythoon> either set CRASHSERVER to /servers/crash-dump-core for the
+      process you want the core file of
+    <teythoon> or make /servers/crash point to crash-dump-core to make this the
+      default for all processes
+    <gnu_srs> does it work now, it did not before?
+    <teythoon> it does for me, never had issues
+    <gnu_srs> k!
+    <teythoon> well, i believe the second option has issues
+    <teythoon> if two processes crash, both may write/create a file in the same
+      location
+
+
+---
+
+If someone is working in this area, they may want to have a look at
+[[GDB_gcore]], and port <http://code.google.com/p/google-coredumper/>, too.