Re: June Snapshot of 6.0 woes under qemu

Michel Talon wrote:

>Hello, 
>
>i have downloaded June snapshot of 6.0 for i386 (and checked md5), and
>tried to run it on qemu (under FreeBSD-5.4, qemu with or without acceleration,
>and with various memory sizes). I try to enter the fixit console, and type
>commands, the console freezes. This is the first time i see that with FreeBSD
>snapshots, qemu runs fine various Linux distros and Solaris. I suspect
>there is some strange bug.
>
>
>  
>
I had the same problem yesterday with a custom build install CD. The 
problem is a lock order reversal:

Fixit# ls
lock order reversal
 1st 0xc16d26e8 ATA state lock (ATA state lock) _at_ /usr/src/sys/dev/ata/ata-all.c:297
 2nd 0xc14611c4 user map (user map) _at_ /usr/src/sys/vm/vm_map.c:2997
KDB: stack backtrace:
kdb_backtrace(0,ffffffff,c0927968,c0928520,c08b464c) at kdb_backtrace+0x29
witness_checkorder(c14611c4,9,c086a271,bb5) at witness_checkorder+0x564
_sx_xlock(c14611c4,c086a271,bb5) at _sx_xlock+0x50
_vm_map_lock_read(c1461180,c086a271,bb5,200dbbb,c) at _vm_map_lock_read+0x37
vm_map_lookup(c7f65b7c,c72d4000,2,c7f65b80,c7f65b70) at vm_map_lookup+0x28
vm_fault(c1461000,c72d4000,2,0,c16e0000) at vm_fault+0x66
trap_pfault(c7f65c44,0,c72d4800) at trap_pfault+0x137
trap(8,28,28,c72d4800,c16d2600) at trap+0x33d
calltrap() at calltrap+0x5
--- trap 0xc, eip = 0xc04d25cc, esp = 0xc7f65c84, ebp = 0xc7f65ca4 ---
ata_pio_read(c1825190,800,129,c17c9d00,c17e8400) at ata_pio_read+0x78
ata_end_transaction(c1825190) at ata_end_transaction+0x8b8
ata_interrupt(c16d2600) at ata_interrupt+0xdf
ithread_loop(c16dd800,c7f65d38,c16dd800,c061b418,0) at ithread_loop+0x11c
fork_exit(c061b418,c16dd800,c7f65d38) at fork_exit+0xa0
fork_trampoline() at fork_trampoline+0x8
--- trap 0x1, eip = 0, esp = 0xc7f65d6c, ebp = 0 ---
panic: vm_fault: fault on nofault entry, addr: c72d4000
cpuid = 0
KDB: enter: panic
[thread pid 26 tid 100010 ]
Stopped at      kdb_enter+0x2b: nop
db>

This is known. See:
http://sources.zabbadoz.net/freebsd/lor.html#101

Andrew


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