From mboxrd@z Thu Jan  1 00:00:00 1970
From: erik quanstrom <quanstro@coraid.com>
Date: Fri, 27 Feb 2009 13:48:31 -0500
To: 9fans@9fans.net
Message-ID: <80203e548baaaca958ded36dcf2a66c3@coraid.com>
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Subject: [9fans] interesting kernel panic
Topicbox-Message-UUID: a9cd87b0-ead4-11e9-9d60-3106f5b1d025

maybe this is a hardware error.  maybe it's
an obscure bug.  it's not immediately clear to me.
we have not had any other panics in the last year.
the only console message is:

Thu Feb 26 15:02:18: panic: newpage
Thu Feb 26 15:02:18: panic: newpage

ktrace /kernel/path f0108f3d f3c71670 <<EOF
estackxcpu1: exiting
cpu0: exiting
 f3c71a00
f3c71610=f0108cd2 f3c71618=f019b206 f3c71644=f014ac5e f3c71658=f0108f3d
f3c7166c=f0108f3d f3c71670=f0108cd6 f3c71678=f014af9c f3c716b0=f0108781
f3c716c8=f019b7f0 f3c716e4=f0146fa9 f3c716f0=f01a8646 f3c716fc=f01a38d5
f3c71708=f01a3eb7 f3c7170c=f01a8878 f3c71714=f01a8b5c f3c71720=f01a3791
f3c71734=f01a8c63 f3c71744=f01a377b f3c71748=f01a3791 f3c71758=f01a9b1c
f3c71764=f01a377b f3c7176c=f01a3791 f3c71770=f01a38d5 f3c7177c=f01a377b
f3c71788=f01a3c24 f3c71794=f01942f7 f3c717a4=f01944cf f3c717b0=f01a38d5
f3c717bc=f01a3d8b f3c717c4=f01a3d8b f3c717dc=f019351b f3c717f0=f018bb05
f3c71820=f01932e5 f3c71838=f011b53d f3c71844=f0109121 f3c71854=f01a377b
f3c71858=f01a3791 f3c71860=f01a38d5 f3c71868=f01a3d8b f3c7186c=f018c2ed
f3c71874=f01a3d8b f3c71880=f01a8b5c f3c71894=f011bd54 f3c718a0=f01a8646
f3c718ac=f01a9701 f3c718bc=f01a8878 f3c718d8=f010854d f3c718dc=f01017b9
f3c718e4=f01a38d5 f3c718f4=f01086fe f3c71900=f018e78c f3c7190c=f01aa6cd
f3c71910=f019b696 f3c71924=f018be5b f3c71934=f019ce1d f3c7195c=f010854d
f3c71968=f01a31e0 f3c71978=f0109547 f3c719ac=f010065d f3c719d4=f010001b
f3c719e4=0000000e f3c719e8=00000006 f3c719ec=00015e27 f3c719f0=00000023
f3c719f4=00010202 f3c719f8=dfffd87c f3c719fc=0000001b
EOF
src(0xf0108f3d); // dumpstack+0x10
src(0xf014af9c); // panic+0xfc
src(0xf01944cf); // newpage+0x91
src(0xf019351b); // fixfault+0x121
src(0xf01932e5); // fault+0xde
src(0xf0109121); // fault386+0x143
src(0xf01086fe); // trap+0x15d
src(0xf010065d); // forkret
//passing interrupt frame; last pc found at sp=0xf3c719ac

acid: src(0xf0109121); // fault386+0x143
/sys/src/9/pc/trap.c:639
 634			panic("user fault: up=0 pc=0x%.8lux addr=0x%.8lux", ureg->pc, addr);
 635
 636		insyscall = up->insyscall;
 637		up->insyscall = 1;
 638		n = fault(addr, read);
>639		if(n < 0){
 640			if(!user){
 641				dumpregs(ureg);
 642				panic("fault: 0x%lux\n", addr);
 643			}
 644			checkpages();

acid: src(0xf019351b); // fixfault+0x121
/sys/src/9/port/fault.c:106
 101
 102		case SG_BSS:
 103		case SG_SHARED:			/* Zero fill on demand */
 104		case SG_STACK:
 105			if(*pg == 0) {
>106				new = newpage(1, &s, addr);
 107				if(s == 0)
 108					return -1;
 109
 110				*pg = new;
 111			}

acid: src(0xf01944cf); // newpage+0x91
/sys/src/9/port/page.c:195
 190
 191		lock(p);
 192		if(p->ref != 0)
 193			panic("newpage");
 194
>195		uncachepage(p);
 196		p->ref++;
 197		p->va = va;
 198		p->modref = 0;
 199		for(i = 0; i < MAXMACH; i++)
 200			p->cachectl[i] = ct;

- erik