Date: Sat, 29 Dec 2012 15:01:55 -0500 From: Chris Ross <cross+freebsd@distal.com> To: Chris Ross <cross+freebsd@distal.com> Cc: freebsd-sparc64@freebsd.org, Marius Strobl <marius@alchemy.franken.de> Subject: Re: Changes to kern.geom.debugflags? Message-ID: <6FC4189B-85FA-466F-AA00-C660E9C16367@distal.com> In-Reply-To: <A947C892-5379-4F70-BFA0-0A7AB94DF0C6@distal.com> References: <7AA0B5D0-D49C-4D5A-8FA0-AA57C091C040@distal.com> <6A0C1005-F328-4C4C-BB83-CA463BD85127@distal.com> <20121225232507.GA47735@alchemy.franken.de> <8D01A854-97D9-4F1F-906A-7AB59BF8850B@distal.com> <A947C892-5379-4F70-BFA0-0A7AB94DF0C6@distal.com>
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On Dec 27, 2012, at 1:15 PM, Chris Ross <cross+freebsd@distal.com> =
wrote:
>=20
> On Dec 27, 2012, at 10:43 AM, Chris Ross wrote:
>>>> FreeBSD/sparc64 ZFS boot block
>> Boot path: /pci@1c,600000/scsi@2/disk@1,0:a
>> Consoles: Open Firmware console =20
>> ERROR: Last Trap: Division by Zero
>>=20
>> {1} ok ctrace
>> No saved state
>> {1} ok=20
>>=20
>> Anything else you can suggest to get debugging information out of =
zfsloader?
>=20
> So, I've started with the tiring process of "printf debugging". I =
have gotten out of
> the loader code, and can show that it's inside of the call to the zfs =
devsw dv_init()
> call where it's failing.
Okay. Many many iterations, and I found out where it's crashing. In
sys/boot/zfs/zfsimpl.c, in dnode_read(), the first line of the while =
loop
is:
uint64_t bn =3D offset / bsize;
And, bsize is calculated from:
int bsize =3D dnode->dn_datablkszsec << SPA_MINBLOCKSHIFT;
When running the code, though, I can confirm that bsize is 0 before =
the divide
is hit, thus causing the divide by zero trap.
I'm going to guess this is a problem with dnode->dn_datablkszsec. Has =
anything
changed recently in zfs_fmtdev, or more likely zfs_get_root() or =
objset_get_dnode(),
which is the callchain right before dnode_read() ?
- Chris
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