Hang near end of kernel probes since r213267 (likely earlier)

[David Wolfskill]

On Sun, Oct 03, 2010 at 02:52:19PM +0300, Andriy Gapon wrote:
> on 03/10/2010 14:28 David Wolfskill said the following:
> [snipped]
> 
> Can't you just drop to DDB prompt and examine where the threads are?

Eh -- thanks for the reality check; I needed that.  :-}

OK; I enabled the KDB & DDB options & rebuilt the kernel; 2nd reboot
after "make installkernel" huhng as before.

Now, unfortunately, the new laptop doesn't have a serial console, so
below is hand-transcribed:

GDB: no debug ports present
KDB: debugger backends: ddb
KDB: current backend: ddb
524288K of memory above 4GB ignored
Copyright (c) 1992-2010 The FreeBSD Project.
Copyright (c) 1979, 1980, 1983, 1986, 1988, 1989, 1991, 1992, 1993, 1994
	The Regents of the University of California. All rights reserved.
FreeBSD is a registered trademark of The FreeBSD Foundation.
FreeBSD 9.0-CURRENT #4 r213380: Sun Oct  3 04:35:15 PDT 2010
...
ugen7.1: <Intel> at usbus7
uhub7: <Intel EHCI root HUB, class 9/0, rev 2.00/1.00, addr 1> on usbus7
uhub0: 2 ports with 2 removable, self powered
uhub1: 2 ports with 2 removable, self powered
uhub2: 2 ports with 2 removable, self powered
uhub4: 2 ports with 2 removable, self powered
uhub5: 2 ports with 2 removable, self powered
uhub6: 2 ports with 2 removable, self powered
uhub3: 6 ports with 6 removable, self powered
cd0 at ata3 bus 0 scbus2 target 0 lun 0
cd0: <TSSTcorp DVD+-RW TS-U633A D200> Removable CD-ROM SCSI-0 device
cd0: 150.000MB/s transfers (SATA 1.x, UDMA5, ATAPI 12bytes, PIO 8192bytes)
cd0: Attempt to query device size failed: NOT READY, Medium not present - tray closed
ada0 at ata2 bus 0 scbus1 target 0 lun 0
ada0: <Seagate ST9250421ASG DE16> ATA-8 SATA 2.x device
ada0: 300.000MB/s transfers (SATA 2.x, UDMA5,  device   
cd0: 150.000MB/s transfers (SATA 1.x, UDMA5, ATAPI 12bytes, PIO 8192bytes)
ada0: 238475MB (488397168 512 byte sectors: 16H 63S/T 16383C)
SMP: AP CPU #1 Launched!
WARNING: WITNESS option enabled, expect reduced performance.
WARNING: DIAGNOSTIC option enabled, expect reduced performance.
uhub7: 6 ports with 6 removable, self powered
ugen2.2: <Broadcom Corp> at usbus2

<previously-descibed hang; I used Ctl+Alt+Esc to enter DDB.

KDB: enter: manual escape to debugger
[ thread pid 12 tid 100017 ]
Stopped at	0xc08d992a = kdb_enter+0x3a:	movl	$0,0xc0e33574 = kdb_why
db> bt
Tracing pid 12 tid 100017 td 0xc94575a0
kdb_enter(c0c737ab,c0caf6cb,1,0,1,...) at 0xc06d992a = kdb_enter+0x3a
scgetc(c0e21950,0,c0caf5f1,2a1,c9457644,...) at 0xc07930a8 = scgetc+0x568
sckbdevent)c92f7500,0,c0fb3ea0,c92f9400,c6da9c4c,...) at 0xc0793424 = sckbdevent+0x1e4
kbdmux_intr(c92f7500,0,c92f9608,c6da9c78,c08e63e3,...) at 0xc069c86b = kbdmux_intr+0x2b
kbdmux_kbd_intr(c92f7500,1,c0ccd301,53,c9194a94,...) at 0xc069ce45 = kbdmux_kbd_intr+0x25
taskqueue_run(c9194a98,0,c0ccd301,4a,c6da9cb8,...) at 0xc08e63e3 = taskqueue_run+0xc3
taskqueue_swi_giant_run(0,0,c0cc37a5,4c3,c945a0b8,...) at 0xc08e6be6 = taskqueue_swi_giant_run+0x66
intr_event_execute_handlers(c91d37f8,c945a080,c0cc37a5,533,c945a0f0,...) at 0xc087e655 = intr_event_execute_handlers+0x125
ithread_loop(c943f980,c6da9d28,c0cc3520,349,c91d37f8,...) at 0xc087f42f = ithread_loop+-x9f
fork_exit(c087f390,c943f980,c6da9d28) at 0xc087c3a8 = fork_exit+0xb8
fork_trampoline() at 0xc0bd5824 = fork_trampoline+0x8
--- trap 0, eip = 0, esp = 0xc6da9d60, ebp = 0 ---
db> 

I used the "ps" command at that point to see that PID 12 is "[intr]",
with the following assignments:

PID	state	wmesg	cmd
100072	I		[irq15: ata1]
100071	I		[irq14: ata0]
100070	I		[irq12: psm0]
100069	I		[irq1: atkbd0]
100067	I		[irq19: cbb0 atapci+]
100064	I		[irq17: fwohci0]
100045	I		[irq1258: iwn0]
100044	I		[irq1257: hdac0]
100035	I		[irq122: uhci2 ehci0+]
100030	I		[irq121: uhci1 ehci4]
100025	I		[irq120: hpet0 ehci0*]
100023	I		[irq19: acpi0]
100018	I		[swi6: task queue]
100017	Run	CPU 1	[swi6: Giant taskq]
100015	I		[swi5: +]
100014	I		[swi2: cambio]
100008	I		[swi4: clock]
100007	I		[swi4: clock]
100006	I		[swi1: netisr 0]
100005	I		[swi3: vm]

I then tried "panic", but that does not appear to have been successful.

Peace,
david
-- 
David H. Wolfskill				david at catwhisker.org
Depriving a girl or boy of an opportunity for education is evil.

See http://www.catwhisker.org/~david/publickey.gpg for my public key.
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