Subject: ffs_alloccg panic
To: None <current-users@NetBSD.ORG>
From: Michael L. VanLoon -- <>
List: current-users
Date: 07/10/1996 23:20:01
With a kernel built 6/18 from sources supped 6/17 or 6/18, I've
recently been getting this panic every few days or so:

panic: ffs_alloccg: map corrupted
stopped at _Debugger+0x4: movl %ebp,%esp

trace reveals:
_ffs_vfree(f8..., f9..., 7b0, 8, 4000) at _ffs_vfree+0x3f5
_ffs_blkpref(f8..., f9..., 24e70, 0, f8...) at _ffs_blkpref+0xd3f
_ffs_blkpref(f8..., 25, 24e70, 4000, 0) at _ffs_blkpref+0x72b
_ffs_blkpref(f8..., 25, 24e70, 4000, f8...) at _ffs_blkpref+0x257
_ffs_realloccg(f8..., 1, 24e70, 1000, 1800) at _ffs_realloccg+0x3aa
_ffs_balloc(f8..., 1, 1200, f8..., f9...) at _ffs_balloc+0x31d
_ffs_write(f9..., 800, f9..., f8..., 13) at _ffs_write+0x297
_vn_write(f8..., f9..., f8...) at _vn_write+0xd0
_sys_write(f8..., f9..., f9..., 0, 800) at _sys_write+0xb1
_syscall() at _syscall+0x287
--- syscall (number 4) ---

The few times I've seen it the sequence of functions in the middle
isn't always exactly the same, but the top and bottom are always the
same.  Does this sound like anything anyone else has seen?  Or sound
like anything someone might have fixed between then and now?

I'm going to try to build a current kernel as soon as I can get one to
compile.  However, I'm not 100% convinced that it's even NetBSD's
fault.  A *lot* of things have changed in my system over the last
month or so (upgraded my 5v AMD 486DX2/80 with a 3v AMD 5x86/133,
upgraded my ATI 8514/Ultra (Mach8) ISA + ATI VGA Basic ISA to a VLB
ATI Mach32, upgraded my X server, libraries and binaries from 3.1.2 to
beta 3.1.2D/E).  Although I have tried to upgrade one thing at a time,
and haven't seen any obvious instabilities from any of the individual
changes (except for a Mach32 bug in the stock 3.1.2 server, which is
why I upgraded it).  But, I'd really like to hear if this sounds
familiar to anyone else before I start yanking my system apart *again*
trying to isolate the problem.

  Michael L. VanLoon                       
        --<  Free your mind and your machine -- NetBSD free un*x  >--
    NetBSD working ports: 386+PC, Mac 68k, Amiga, Atari 68k, HP300, Sun3,
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    NetBSD ports in progress: PICA, others...

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