Date: Thu, 22 Feb 2001 17:28:55 +0200 From: Maxim Sobolev <sobomax@FreeBSD.org> To: John Baldwin <jhb@FreeBSD.org> Cc: "Alexander N. Kabaev" <ak03@gte.com>, current@FreeBSD.org, Dag-Erling Smorgrav <des@ofug.org> Subject: Re: A possible bug in the interrupt thread preemption code [Was: Message-ID: <3A953037.780CDCAB@FreeBSD.org> References: <XFMail.010222061816.jhb@FreeBSD.org>
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John Baldwin wrote: > On 22-Feb-01 Maxim Sobolev wrote: > > >> > 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. > > > > It's already have INVARIANTS, MUTEX_DEBUG, WITNESS and WITNESS_DDB. > > Hmm, ouch, you do'nt want MUTEX_DEBUG, that'll slow your system to a crawl. It doesn't really matter, because system can't even boot into single-user due to panic. > >> 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'. > > > > Ok, I'll try so. > > > > -Maxim > > It will still panic, just hopefully a better panic. I did understand that, but the panic I see after the change is exactly the same as before. Any other ideas? -Maxim To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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