Date: Wed, 17 Dec 1997 18:42:38 +0000 (GMT) From: Terry Lambert <tlambert@primenet.com> To: mike@smith.net.au (Mike Smith) Cc: sclawson@bottles.cs.utah.edu, ivt@gamma.ru, tlambert@primenet.com, freebsd-hackers@freebsd.org Subject: Re: panic: blkfree: freeling free block/frag Message-ID: <199712171842.LAA02077@usr02.primenet.com> In-Reply-To: <199712170635.RAA01913@word.smith.net.au> from "Mike Smith" at Dec 17, 97 05:05:38 pm
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> > I've been getting ``freeing free block'' panics fairly often when > > our main server is doing a bunch of large compiles. A couple weeks > > ago I finally caught it in the act. One of my compiles died and I > > found a source file with exactly 8k of gunk, sitting nicely on an 8k > > boundary (this was on an 8k/1k filesystem). The interesting thing > > about the file was it's list of direct blocks: > > > > 0: 179bb8 > > 1: 179bc0 > > 2: 179bc8 > > 3: 179bd0 > > 4: 179bd8 > > 5: 79be0 > > 6: 179be8 > > 7: 0 > > > > All nicely clustered...except for that sixth one. At first I > > thought that the clustering code was at fault, but disk block 79be0 > > was untouched, and the `real' disk block (179be0) had the correct data > > for the new file. So, the list of blocks in the inode was corrupted > > sometime after the data blocks for the file were written. > > Single-bit memory error, perhaps? Still, keep an eye on it... If this panic'ed, you need to look at the stack. I would prefer you look at the stack for #5. I do not believe this is a single bit error. I believe this is the same problem I have been seeing. Does your ethernet hardware address begin with 00 00? Look at the stack for the routines up from the routine in which it panic'ed, and see if (and how) it might have been stomped. There is no such thing as random data in the kernel (I will argue the random device with you nit-pickers, if you insist ;-)). Terry Lambert terry@lambert.org --- Any opinions in this posting are my own and not those of my present or previous employers.
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