[panic] vm_page_unwire: page 0xfffffe02377e42a0's wire count is zero

[Dominic Fandrey]

Finally I got some hard data in the "stopping amd causes a freeze" case.

I turned off xdm and reproduced the panic a couple of times by creating
high tmpfs load (building chromium on tmpfs) and sending SIGTERM to amd.
I got a couple of panics that produced many screens of output but
instantly rebooted.

Note that nothing was actually mounted by amd, when SIGTERM was sent.

But once the system froze instead. I took a picture, but it turned out
I was actually rewarded with a textdump, which I am willing to mail to
all interested parties.

I still don't get cores (the system is set up for minidumps), but that's
much better than just saying that the system freezes/reboots when I do
a, b and c.

Any way, here is the juice:

FreeBSD 9.2-PRERELEASE #0 r254857: Sun Aug 25 16:28:26 CEST 2013
    root at mobileKamikaze.norad:/usr/obj/HP6510b-9/amd64/usr/src/sys/HP6510b-9

db:0:kdb.enter.panic>  run lockinfo
db:1:lockinfo> show locks
No such command
db:1:locks>  show alllocks
No such command
db:1:alllocks>  show lockedvnods
Locked vnodes
db:0:kdb.enter.panic>  show pcpu
cpuid        = 1
dynamic pcpu = 0xffffff807ee89280
curthread    = 0xfffffe01c80fd490: pid 3070 "amd"
curpcb       = 0xffffff824f85ad00
fpcurthread  = 0xfffffe01c80fd490: pid 3070 "amd"
idlethread   = 0xfffffe000521b000: tid 100004 "idle: cpu1"
curpmap      = 0xffffffff813f1e18
tssp         = 0xffffffff8145fb68
commontssp   = 0xffffffff8145fb68
rsp0         = 0xffffff824f85ad00
gs32p        = 0xffffffff8145dca0
ldt          = 0xffffffff8145dce0
tss          = 0xffffffff8145dcd0
db:0:kdb.enter.panic>  bt
Tracing pid 3070 tid 100138 td 0xfffffe01c80fd490
kdb_enter() at kdb_enter+0x3b/frame 0xffffff824f85a850
panic() at panic+0x1c6/frame 0xffffff824f85a950
vm_page_unwire() at vm_page_unwire+0xf5/frame 0xffffff824f85a980
vm_fault_unwire() at vm_fault_unwire+0xb2/frame 0xffffff824f85a9c0
vm_map_delete() at vm_map_delete+0xcf/frame 0xffffff824f85aa30
vm_map_remove() at vm_map_remove+0x59/frame 0xffffff824f85aa60
vmspace_exit() at vmspace_exit+0xc7/frame 0xffffff824f85aa90
exit1() at exit1+0x3e0/frame 0xffffff824f85ab00
sys_sys_exit() at sys_sys_exit+0xe/frame 0xffffff824f85ab10
amd64_syscall() at amd64_syscall+0x5ea/frame 0xffffff824f85ac30
Xfast_syscall() at Xfast_syscall+0xf7/frame 0xffffff824f85ac30
--- syscall (1, FreeBSD ELF64, sys_sys_exit), rip = 0x800af5b3c, rsp = 0x7fffffffd8c8, rbp = 0x7fffffffdaa8 ---


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