Crash with FreeBSD 6.1 STABLE of today

[Robert Watson]

On Wed, 21 Jun 2006, Martin Blapp wrote:

> I just upgraded from 5.5 (stable btw.) to 6.1 and after 10 hours I got a 
> nice panic. Does this look like some tty problem ?

It looks like a tty or devfs problem.

> This is the machine which made that many problems with PREEMTION enabled in 
> earlier releases of 5.x. Is it possible that I'm hitting now again the same 
> bugs or is it clearly a tty related problem ?

I'm not sure there's evidence it's caused by preemption, but it's not 
impossible that preemption makes it more likely to happen, or facilitates it 
happening on non-SMP systems.  Wojciech Koszek has recently been looking into 
devfs-related races that trigger for pty's, which could be relevant to what 
you're seeing, so I've CC'd him.

Robert N M Watson
Computer Laboratory
University of Cambridge

>
> kgdb /var/core/kernel.debug /var/core/vmcore.6
>
> #0  0xc0663002 in doadump ()
> #1  0xc066355e in boot ()
> #2  0xc06638b5 in panic ()
> #3  0xc085c6b6 in trap_fatal ()
> #4  0xc085c3bf in trap_pfault ()
> #5  0xc085bfb5 in trap ()
> #6  0xc0848bea in calltrap ()
> #7  0xc0693b51 in ttymodem ()
> #8  0xc0698362 in ptcclose ()
> #9  0xc0638a6f in giant_close ()
> #10 0xc06162bf in devfs_close ()
> #11 0xc086dc1c in VOP_CLOSE_APV ()
> #12 0xc06c87e2 in vn_close ()
> #13 0xc06c974a in vn_closefile ()
> #14 0xc06162e7 in devfs_close_f ()
> #15 0xc0642cdc in fdrop_locked ()
> #16 0xc0642c29 in fdrop ()
> #17 0xc06411c7 in closef ()
> #18 0xc063e329 in close ()
> #19 0xc085c9f7 in syscall ()
> #20 0xc0848c3f in Xint0x80_syscall ()
> #21 0x00000033 in ?? ()
> Previous frame inner to this frame (corrupt stack?)
>
> Unfortunaltly I get this with the debug kernel.
> Does one have to boot with the debug.kernel itself
> to get a trace which is usable ?
>
> kgdb /var/core/kernel.debug /var/core/vmcore.6
>
> kgdb: kvm_read: invalid address (0x21)
> kgdb: kvm_read: invalid address (0x21)
> kgdb: kvm_read: invalid address (0x21)
> kgdb: kvm_read: invalid address (0x21)
> kgdb: kvm_read: invalid address (0x21)
> kgdb: kvm_read: invalid address (0x21)
> kgdb: kvm_read: invalid address (0x21)
> kgdb: kvm_read: invalid address (0x21)
> kgdb: kvm_read: invalid address (0x21)
> kgdb: kvm_read: invalid address (0x21)
> kgdb: kvm_read: invalid address (0x21)
> kgdb: kvm_read: invalid address (0x21)
> kgdb: kvm_read: invalid address (0x21)
> kgdb: kvm_read: invalid address (0x21)
> kgdb: kvm_read: invalid address (0x21)
> kgdb: kvm_read: invalid address (0x21)
> kgdb: kvm_read: invalid address (0x21)
> kgdb: kvm_read: invalid address (0x21)
> kgdb: kvm_read: invalid address (0x21)
> kgdb: kvm_read: invalid address (0x21)
> kgdb: kvm_read: invalid address (0x21)
>
> Martin Blapp, <mb at imp.ch> <mbr at FreeBSD.org>
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