hang on amd64 machine

[Kurt Schreiner <ks%ub.uni-mainz.de@localhost>]

Hi,

while compiling a fresh userland on my dual-opteron machine
(8GB Ram, IOMMU disabled) the machine "hangs": compile stopped,
systat on another ssh session is still running, but no new
processes can be started. Breaking to ddb shows this:

db{0}> bt
breakpoint() at netbsd:breakpoint+0x5
comintr() at netbsd:comintr+0x53a
Xintr_ioapic_edge4() at netbsd:Xintr_ioapic_edge4+0xef
--- interrupt ---
mutex_vector_enter() at netbsd:mutex_vector_enter+0xd1
ffs_sync() at netbsd:ffs_sync+0xc6
VFS_SYNC() at netbsd:VFS_SYNC+0x33
sync_fsync() at netbsd:sync_fsync+0x96
VOP_FSYNC() at netbsd:VOP_FSYNC+0x7e
sched_sync() at netbsd:sched_sync+0x14f
db{0}> mach cpu 1
using CPU 1
db{0}> bt
x86_stihlt() at netbsd:x86_stihlt+0x6
idle_loop() at netbsd:idle_loop+0xa8
Bad frame pointer: 0xffff80005410c020
db{0}> mach cpu 2
using CPU 2
db{0}> bt        
x86_stihlt() at netbsd:x86_stihlt+0x6
idle_loop() at netbsd:idle_loop+0xa8
Bad frame pointer: 0xffff800054117be0
db{0}> mach cpu 3
using CPU 3
db{0}> bt        
__cpu_simple_lock_try() at netbsd:__cpu_simple_lock_try+0x9
pmap_page_remove() at netbsd:pmap_page_remove+0x40
genfs_do_putpages() at netbsd:genfs_do_putpages+0xa2f
VOP_PUTPAGES() at netbsd:VOP_PUTPAGES+0x7e
vinvalbuf() at netbsd:vinvalbuf+0x47
vclean() at netbsd:vclean+0x194
getcleanvnode() at netbsd:getcleanvnode+0xcd
getnewvnode() at netbsd:getnewvnode+0x33
tmpfs_alloc_vp() at netbsd:tmpfs_alloc_vp+0x8b
tmpfs_alloc_file() at netbsd:tmpfs_alloc_file+0x136
VOP_CREATE() at netbsd:VOP_CREATE+0x73
vn_open() at netbsd:vn_open+0x257
sys_open() at netbsd:sys_open+0xe7
syscall() at netbsd:syscall+0xaf

Continuing execution (c) and breaking to ddb some time later
shows the same picture every time...

Anything I could do to help debugging this?

Btw: Having memory reduced to 4G or below via PHYSMEM_MAX_SIZE I wasn't
able to trigger this (cross compiling distributon/release for some
5 architectures, rsyncing internal and external file systems)

Kurt