Panic in 7.1-PRERELEASE (was: Re: kgdb on sparc64)

Ruben de Groot mail25 at
Wed Nov 19 00:03:56 PST 2008

On Sun, Nov 09, 2008 at 07:32:32PM +0100, Marius Strobl typed:
> On Wed, Nov 05, 2008 at 08:56:30PM +0100, Ruben de Groot wrote:
> > > For your purposes it's probably simpler to just build a
> > > kernel with debugger by adding "options DDB", "options KDB"
> > > and "makeoptions DEBUG=-g". Then when the kernel panics
> > > just enter "backtrace" on the console. With a X1 you
> > > most likely use serial console anyway so you can easily
> > > capture the output.
> > 
> > I'll build a kernel with those options just in case. But
> > would rather not use it on this particular machine, as it is 
> > a production server and should not be down for extended periods
> > of time.
> If you additionally either also add "options KDB_TRACE" and
> "options KDB_UNATTENDED" or set "debug.trace_on_panic=1"
> and "debug.debugger_on_panic=0" via sysctl(8) with a
> debugger-enabled kernel, the debugger will automatically
> print a backtrace to the console and then reboot the
> machine and thus minimizing downtime. Printing the
> backtrace might require the latest 7-STABLE though.
> > Meanwhile, moving over websites to another machine (another X1,
> > but running -current) that seems to be more stable ATM.
> > 
> That's what puzzles me as every sparc64-specific change
> in 7-STABLE since 7.0-RELEASE also is in -current except
> for one stricter check in -current. So I guess you're
> hitting one of the MI stability issues people are
> reporting for 7.1-PRERELEASE.

It took some time, but I finally managed to get a backtrace today,
with a newly compiled 7-stable kernel:

FreeBSD 7.1-PRERELEASE FreeBSD 7.1-PRERELEASE #5: Mon Nov 10 21:25:55 CET 2008     root at  sparc64

panic: trap: data access error
cpuid = 0
KDB: stack backtrace:
panic() at panic+0x1c8
trap() at trap+0x4d0
-- data access error %o7=0xc00bac60 --
dc_mii_writebit() at dc_mii_writebit+0xd8
dc_miibus_writereg() at dc_miibus_writereg+0x2a0
miibus_writereg() at miibus_writereg+0x64
mii_phy_reset() at mii_phy_reset+0x7c
mii_phy_tick() at mii_phy_tick+0x154
amphy_service() at amphy_service+0x164
mii_tick() at mii_tick+0x1c
dc_tick() at dc_tick+0x1ec
softclock() at softclock+0x3c4
ithread_loop() at ithread_loop+0x21c
fork_exit() at fork_exit+0x88
fork_trampoline() at fork_trampoline+0x8
Uptime: 4d22h16m5s
Dumping 1024 MB (4 chunks)
  chunk at 0: 268435456 bytes ... ok
  chunk at 0x20000000: 268435456 bytes ... ok
  chunk at 0x40000000: 268435456 bytes ... ok
  chunk at 0x60000000: 268435456 bytes ... ok

Dump complete
Automatic reboot in 15 seconds - press a key on the console to abort

LOM event: +65d+13h48m37s host reset
Resetting ...

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