On 22-Feb-01 Maxim Sobolev wrote:
> John Baldwin wrote:
>
>> On 22-Feb-01 Maxim Sobolev wrote:
>> > Dag-Erling Smorgrav wrote:
>> >
>> >> Maxim Sobolev <[EMAIL PROTECTED]> writes:
>> >> > It's not an ata specific problem, but rather a problem of all ISA
>> >> > devices (I have an ISA based ata controller).
>> >>
>> >> I don't think it has anything to do with ISA. I've had similar
>> >> problems on a PCI-only system (actually, PCI+EISA motherboard with no
>> >> EISA cards) with no ATA devices (disks, CD-ROM and streamer are all
>> >> SCSI).
>> >>
>> >> Considering that backing out rev 1.14 of ithread.c eliminates the
>> >> panics, and that that revision is supposed to enable interrupt thread
>> >> preemption, and that the crashed kernels show signs of stack smashing,
>> >> I'd say the cause is probably a bug in the preemption code.
>> >
>> > Update: the bug is still here, as of -current from 22 Feb. Hovewer, this
>> > time
>> > it even doesn't let to boot into single-user with following panic message:
>> > kernel trap 12 with interrupts disabled
>> > panic: mutex sched lock recursed at ../../kern/kern_synch.c:872
>>
>> Errrr. That would be something that is leaking sched_lock. Hmm...
>>
>> Got a backtrace? What is really annoying is that preemption has been in the
>> kernel since Feb 1. I just accidentally turned it off in the ithread code
>> reorganization and then turned it back on. It was off for a few hours after
>> only being on for 2 weeks, and now everyone magically has problems.
>
> Here it is (from DDB):
> panic(c027de93,c0297409,c027f878,368,80286)
> _mtx_assert(c02ea000,9,c027f878,368,80286)
> mi_switch(c32c5da0,3,c02cea44,c357be98)
> ithread_schedule(c0747c00,1)
> sched_ithd(e)
> Xresume14()
> --- interrupt, eip = 0xc025b60f, esp = 0x80296, ebp = 0xc357bf08 ---
> trap(18, 10, 10,c01597b6,20)
> calltrap()
> --- trap 0x9, eip = 0xc025a5de, esp = 0xc357bf50, ebp = 0xc357bf64 ---
> sw1b(c0146cbc,c0146cbc,c32c5da0,c357bf94)
> ithread_loop(c0747c00,c357bfa8)
> fork_exit(c0146cbc,c0747c00,c357bfa8)
> fork_trampoline()
*sigh* This is why enabling interrupts in trap() is such a bad idea. If we
get a trap in the scheduler, then lots of bad crap starts to happen because we
can get an interrupt while we are in a trap. :( Can you compile your kernel with
INVARIANTS on though, as I think the kernel should've panic'd earlier if it is
doing what I think it is doing. Also, if you are feeling industrious, edit
sys/i386/i386/trap.c and comment out the enable_intr() call near the beginning
of the trap() function right after the printf for 'kernel trap %d with
interrupts disabled'.
> -Maxim
--
John Baldwin <[EMAIL PROTECTED]> -- http://www.FreeBSD.org/~jhb/
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