Subject: analog hits a UVM bug?
To: None <firstname.lastname@example.org>
From: Robby Griffin <rmg@MIT.EDU>
Date: 10/11/2000 14:59:18
I'm using analog to generate cumulative statistics for a group of sites
at work, but the machine I'm using nearly always drops into the debugger
during the run. I'm wondering whether this is likely to indicate a kernel
bug or whether it's just a "Don't Do That Then" situation.
I don't have an indication of what the panic was with this trace, but in
the past it's been something along the lines of "page already freed".
_Debugger(3,0,c0e0efc4,d5322e58,c028a518) at _Debugger+0x4
_panic(c028a492,c0e0efc4,d5322e70,c028ba0b,c0e0efc4) at _panic+0x55
_uvm_page_lookup_freelist(c0e0efc4,c0e0efc4,d4faf9f0,0,d5322e84) at _uvm_page_lookup_freelist+0x50
_uvm_pagefree(c0e0efc4) at _uvm_pagefree+0x1c7
_uvm_anfree(d4faf9f0) at _uvm_anfree+0x6f
_amap_wipeout(d5131b48,d5324d44,d5324d44,0,d5322ecc) at _amap_wipeout+0x3b
_amap_unref(d5324d44,0) at _amap_unref+0x1a
_uvm_unmap_detach(d5324c90,0,d5102dc4,d531300c,d5324c90) at _uvm_unmap_detach+0x31
_uvm_unmap(d5102dc4,0,bfbfe000,d5102dc4,d5322f2c) at _uvm_unmap+0x5d
_uvm_deallocate(d5102dc4,0,bfbfe000) at _uvm_deallocate+0x38
_exit1(d531300c,0,d5322fa8,c029ffde,d531300c) at _exit1+0x12b
_sys_exit(d531300c,d5322f88,d5322f80,0,ffffffff) at _sys_exit+0x14
_syscall() at _syscall+0x20e
--- syscall (number 1) ---
syncing disks... 10 8 done
dump to dev 0,1 not possible
NetBSD khwarizmi 1.4.2 NetBSD 1.4.2 (GENERIC+MAXUSERS256) #1: Wed Jun 28 03:32:21 EDT 2000 root@khwarizmi:/usr/src/sys/arch/i386/compile/GENERIC+MAXUSERS256 i386
(It really is just GENERIC with maxusers set to 256)
The machine has 512M ram but only about 240M swap for whatever reason,
hence the lack of dump.
I'm running a series of analog processes from a perl script, operating
on about 2.5G of logs. One run of analog covers all the data, another
covers all the data from this month, and there are batches of analog
runs covering individual sites within the data. The crashes do not
always occur on the same analog process and occasionally the entire run
is completed without a problem.
For the cumulative analysis of all logs, the analog process size exceeds
128M. In the past this resulted in an analog coredump due to my shell
resource limits. I've been setting the limits higher before doing the
runs lately, and that's when I've been seeing uvm-related crashes. In
particular, as an unprivileged user,
datasize 131072 kbytes 384000
stacksize 2048 kbytes 16384
memoryuse 480924 kbytes
descriptors 64 200
memorylocked 160308 kbytes 256000
maxproc 80 200
If this looks like a bug I'll go file a PR, I'm just curious whether this
is an expected or known behavior.