Hi,

One of our servers (Dell PE1800) running NetBSD/amd64 4.0_RC1 is very unstable 
since the 3.1.1 to 4.0_RC1 upgrade (upgrade is a wrong word, it was installed 
from scratch). We see quite often "fatal double fault in supervisor mode" 
followed by "trap 13". The whole machine hangs and there is no trace seen on the 
console even though we see "Begin traceback..."

What makes it harder is that the kernel debugger does not work (Ctrl+Alt+Esc) at 
all even though this is the diff against GENERIC.

Any ideas?

Martti


--- GENERIC     2007-09-06 11:04:40.000000000 +0300
+++ D146  2007-09-10 08:08:09.000000000 +0300
@@ -24,7 +24,7 @@

  #ident                 "GENERIC-$Revision: 1.120.2.12 $"

-maxusers       32              # estimated number of users
+maxusers       128             # estimated number of users

  # delay between "rebooting ..." message and hardware reset, in milliseconds
  #options       CPURESET_DELAY=2000
@@ -87,12 +87,12 @@
  # Because gcc omits the frame pointer for any -O level, the line below
  # is needed to make backtraces in DDB work.
  #
-#makeoptions   COPTS="-O2 -fno-omit-frame-pointer"
-#options       DDB             # in-kernel debugger
+makeoptions    COPTS="-O2 -fno-omit-frame-pointer"
+options        DDB             # in-kernel debugger
  #options       DDB_HISTORY_SIZE=512    # enable history editing in DDB
  #options       KGDB            # remote debugger
  #options       KGDB_DEVNAME="\"com\"",KGDB_DEVADDR=0x3f8,KGDB_DEVRATE=9600
-#makeoptions   DEBUG="-g"      # compile full symbol table
+makeoptions    DEBUG="-g"      # compile full symbol table

  # Compatibility options
  options        COMPAT_15       # compatibility with NetBSD 1.5,
@@ -955,3 +955,8 @@
  options VERIFIED_EXEC_FP_MD5

  options PAX_MPROTECT=0                 # PaX mprotect(2) restrictions
+
+# Other settings
+options        MULTIPROCESSOR
+options        NMBCLUSTERS=16384
+options        MSGBUFSIZE=65536