Advice sought 'panic: ifree freeing inode.'

[H. Morrow Long [Systems Center]]

	We seem to have an insidious 4.2bsd kernel bug that has been
	the cause of at least 4 panics in the past 2 months.  We have a
	4Mbyte Vax 11/780 with 1 rp06 and 3 SI eagles that has been
	running 4.2bsd since 12/10/84 (4.1bsd before that).  I believe
	I have found a fix that will cure this behavior (we end up
	having to clear many inodes in the root filesystem before fsck
	gives us a clean bill of health, then we must 'restore' them,
	files and directories have also mysteriously been mangled) but
	would like to hear of similar experiences from other sites.
	This is an the relevant portion of our downlog:
	
DUMP Fri Jan 11 17:22:03 EST 1985:	downtime  0 days, 00:14:11
	Zero dump.

SOFT Mon Jan 14 08:41:39 EST 1985:	downtime  0 days, 08:51:53
	panic: ifree freeing inode.

SOFT Mon Jan 14 08:56:57 EST 1985:	downtime  0 days, 00:09:43
	Fixing filesystem after crash.

SOFT Thu Jan 17 09:15:36 EST 1985:	downtime  0 days, 07:25:57
	dev = 0x0, ino = 51, fs = /
	panic: ifree: freeing free inode.

SOFT Sun Jan 27 10:59:34 EST 1985:	downtime  1 days, 09:06:52
	dev = 0x0, ino = 115, fs = /
	panic: ifree: freeing free inode.


PM Mon Jan 28 18:15:19 EST 1985:	downtime  0 days, 00:12:29
	DEC Preventive Maintenence.

INSTALL Mon Feb  4 22:23:25 EST 1985:	downtime  0 days, 04:08:39
	Brought up new kernel (with accounting changes),
	moved /usr/spool to a separate filesystem on the 'new' eagle -
	hp4.

DUMP Tue Feb 12 17:36:41 EST 1985:	downtime  0 days, 00:13:03
	Scheduled zero dump performed.

SOFT Fri Feb 22 09:48:31 EST 1985:	downtime  0 days, 06:44:19
	dev = 0x0, ino = 75, fs = /
	panic: ifree: freeing free inode.


SOFT Mon Feb 25 22:57:55 EST 1985:	downtime  0 days, 05:17:43
	machine check f:  ib cache par fault
	cpues 10084 upc 61 va/viba 800150f8 dreg 0 tber 7c01 0
	timo 150f8 parity bff7 sbier 8002 pc 800150f8 psl c00004 sbifs 2000000
	panic: mchk 
	trap type 2, code = 0, pc = 800016b5
	panic: Reserved operand

	Problem occurred after dump aborted, during shutdown for DEC
	PM.

SOFT Tue Feb 26 20:59:30 EST 1985:	downtime  0 days, 01:34:30
	ode = c15a5ef4, pc = 80013438
	panic: Segmentation fault

	Problem occurred during dump

-- 

				H. Morrow Long
				ITT-ATC Systems Center,
				1 Research Drive Shelton, CT  06484
				Phone #: (203)-929-7341 x. 634
	
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