ia64/xen-unstable

changeset 3768:523d096fe965

bitkeeper revision 1.1166 (420b94b19VPINEpnyrORsIwqTctjAA)

Add in a very brief description of how it's supposed to work.
author sos22@douglas.cl.cam.ac.uk
date Thu Feb 10 17:06:57 2005 +0000 (2005-02-10)
parents e1c1afb7b55b
children fe75fd018eb7
files .rootkeys docs/misc/crashdb.txt
line diff
     1.1 --- a/.rootkeys	Thu Feb 10 16:56:14 2005 +0000
     1.2 +++ b/.rootkeys	Thu Feb 10 17:06:57 2005 +0000
     1.3 @@ -18,6 +18,7 @@ 418a3248xjIqmNKo0v_XQSfAvlBGFw docs/html
     1.4  41c0c4116itF389v0CEWcmzue6zJkA docs/misc/VMX_changes.txt
     1.5  4022a73cgxX1ryj1HgS-IwwB6NUi2A docs/misc/XenDebugger-HOWTO
     1.6  412f4bd9sm5mCQ8BkrgKcAKZGadq7Q docs/misc/blkif-drivers-explained.txt
     1.7 +420b949cy9ZGzED74Fz_DaWlK7tT4g docs/misc/crashdb.txt
     1.8  40d6ccbfKKBq8jE0ula4eHEzBiQuDA docs/misc/xen_config.html
     1.9  410a4c2bAO_m_l4RsiiPHnZ4ixHWbQ docs/misc/xend.tex
    1.10  3f9e7d564bWFB-Czjv1qdmE6o0GqNg docs/src/interface.tex
     2.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     2.2 +++ b/docs/misc/crashdb.txt	Thu Feb 10 17:06:57 2005 +0000
     2.3 @@ -0,0 +1,36 @@
     2.4 +Xen crash debugger notes
     2.5 +------------------------
     2.6 +
     2.7 +Xen has a simple gdb stub for doing post-mortem debugging i.e. once
     2.8 +you've crashed it, you get to poke around and find out why.  There's
     2.9 +also a special key handler for making it crash, which is handy.
    2.10 +
    2.11 +You need to have crash_debug=y set when compiling to enable the crash
    2.12 +debugger (so go ``export crash_debug=y; make'', or ``crash_debug=y
    2.13 +make'' or ``make crash_debug=y''), and you also need to enable it on
    2.14 +the Xen command line, by going e.g. cdb=com1.  If you need to have a
    2.15 +serial port shared between cdb and the console, try cdb=com1H.  CDB
    2.16 +will then set the high bit on every byte it sends, and only respond to
    2.17 +bytes with the high bit set.  Similarly for com2.
    2.18 +
    2.19 +The next step depends on your individual setup.  This is how to do
    2.20 +it for a normal test box in the SRG:
    2.21 +
    2.22 +-- Make your test machine crash.  Either a normal panic or hitting
    2.23 +   'C-A C-A C-A %' on the serial console will do.
    2.24 +-- Start gdb as ``gdb ./xen-syms''
    2.25 +-- Go ``target remote serial.srg:12331'', where 12331 is the second port
    2.26 +   reported for that machine by xenuse. (In this case, the machine is
    2.27 +   bombjack)
    2.28 +-- Go ``add-symbol-file vmlinux''
    2.29 +-- Debug as if you had a core file
    2.30 +-- When you're finished, go and reboot your test box.  Hitting 'R' on the
    2.31 +   serial console won't work.
    2.32 +
    2.33 +At one stage, it was sometimes possible to resume after entering the
    2.34 +debugger from the serial console.  This seems to have rotted, however,
    2.35 +and I'm not terribly interested in putting it back.
    2.36 +
    2.37 +As soon as you reach the debugger, we disable interrupts, the
    2.38 +watchdog, and every other CPU, so the state of the world shouldn't
    2.39 +change too much behind your back.