Can't panic from debugger
rwatson at FreeBSD.org
Sun Dec 23 05:16:31 PST 2007
On Sun, 23 Dec 2007, Erwin Lansing wrote:
> The amd64 nodes in the pointyhat cluster are starting to behave quite
> interestingly. They stop to respond to ssh, but are still answering ping.
> More worrying is that I cannot get a useful dump out of it, as a panic from
> the debugger just hangs there, and all I am left with is to pull the plug.
> This even happens on a normal working system after entering the debugger, of
> which there is a typescript below.
> FreeBSD hammer1.isc.gumbysoft.com 8.0-CURRENT FreeBSD 8.0-CURRENT #11: Sat
> Dec 8 17:18:09 UTC 2007
> root at danner.isc.gumbysoft.com:/usr/obj/usr/src/sys/HAMMER amd64
I discovered yesterday that I was seeing the same problem on a dual-cpu,
dual-core box in the netperf cluster:
cheetah-rwatson# sysctl debug.kdb.enter=1
debug.kdb.enter:K DB0: enter: sysctl debug.kdb.enter
[thread pid 1136 tid 100091 ]
Stopped at kdb_enter+0x3d: movq $0,0x603f38(%rip)
db> show pcpu
cpuid = 0
curthread = 0xffffff00032e56a0: pid 1136 "sysctl"
curpcb = 0xffffffffabae7d40
fpcurthread = none
idlethread = 0xffffff00010d56a0: pid 11 "idle: cpu0"
spin locks held:
panic: from debugger
cpuid = 0
I *can* get a coredump if I directly "call doadump" and then "reset", but I
can't get one if I just do "panic".
Robert N M Watson
University of Cambridge
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