dev/isp panic (was Re: CAM Target Layer and dev/isp)

[Gary Palmer]

On Thu, Jul 19, 2012 at 05:22:21AM -0700, Trent Nelson wrote:
> On 7/19/12 1:55 AM, "Andriy Gapon" <avg at FreeBSD.org> wrote:
> 
> >on 18/07/2012 17:00 Matthew Jacob said the following:
> >> --------------
> >> 
> >> db> bt
> >> Tracing pid 12 tid 100062 td 0xfffffe001c00f470
> >> acpi_timer_get_timecount() at 0xffffffff803ccfc6 =
> >> acpi_timer_get_timecount+0x16
> >> DELAY() at 0xffffffff80ce68c3 = DELAY+0x83
> >> ns8250_putc() at 0xffffffff807a17ba = ns8250_putc+0x9a
> >> uart_cnputc() at 0xffffffff807a3b85 = uart_cnputc+0x75
> >> cnputc() at 0xffffffff808e9cbc = cnputc+0x4c
> >> cnputs() at 0xffffffff808ea0f5 = cnputs+0x35
> >> putbuf() at 0xffffffff8097400c = putbuf+0xac
> >> kvprintf() at 0xffffffff80972643 = kvprintf+0x83
> >> vprintf() at 0xffffffff80973b15 = vprintf+0x85
> >> printf() at 0xffffffff80973be7 = printf+0x67
> >> isp_prt() at 0xffffffff805c15a0 = isp_prt+0xd0
> >> isp_async() at 0xffffffff805c6736 = isp_async+0x356
> >> isp_intr() at 0xffffffff805b854c = isp_intr+0x13ac
> >> isp_platform_intr() at 0xffffffff805c1fd9 = isp_platform_intr+0x99
> >> intr_event_execute_handlers() at 0xffffffff80907214 =
> >> intr_event_execute_handlers+0x104
> >> ithread_loop() at 0xffffffff809089a6 = ithread_loop+0xa6
> >> fork_exit() at 0xffffffff809038ef = fork_exit+0x11f
> >> fork_trampoline() at 0xffffffff80c5139e = fork_trampoline+0xe
> >> --- trap 0, rip = 0, rsp = 0xffffff9178bd3cf0, rbp = 0 ---
> >> db> x/s panicstr
> >> 0xffffffff8130fd08 = panicstr:
> >> 
> >> 
> >> -------------
> >> 
> >> Hmm. No panic string because it wasn't a panic. isp driver is trying to
> >> (successfully) print something and this blew up in the ACPI code. If
> >>there was a
> >> bad string it would have blown up in kvprintf.  At least that's my read
> >>of this.
> >
> >I think that the vague reference to ACPI is unnecessarily too vague,
> >given the
> >quite obvious stack trace (hint: DELAY) and both simplicity and utility of
> >acpi_timer_get_timecount (essentially an I/O read operation).
> >But there is no indication in the above stack trace that something blew
> >up at
> >all (no magic words like "panic", "trap").
> 
> Hrm.  What else would cause 'db>' to show up on the console?  Ctrl-Alt-Esc
> and hitting a breakpoint are all I can think of at the moment -- and
> neither of those are applicable here.

Is there a serial console attached?  Sending BREAK via serial can also
do it (or used to anyway), and some terminal servers send BREAK when they
reset/reboot.

The fact you were in ns8250_putc() could point at a serial port issue.

Gary