usb/109397: [panic] on boot from USB flash

[M. Warner Losh]

The following reply was made to PR usb/109397; it has been noted by GNATS.

From: "M. Warner Losh" <imp at bsdimp.com>
To: coumarin at gmail.com
Cc: freebsd-gnats-submit at freebsd.org
Subject: Re: usb/109397: [panic] on boot from USB flash
Date: Thu, 22 Feb 2007 09:17:05 -0700 (MST)

 In message: <45DC8EBF.7060806 at gmail.com>
             Alexander Shiryaev <coumarin at gmail.com> writes:
 : M. Warner Losh wrote:
 : > You might also try setting / and /usr to read only to see if the
 : > corruption occurs during boot or before.
 : > 
 : > Warner
 : > 
 : 
 : I have following slice structure on USB flash (bsdlabel /dev/da0s1):
 : 
 : # /dev/da0s1:
 : 8 partitions:
 : #        size   offset    fstype   [fsize bsize bps/cpg]
 :    a:   262144       16    4.2BSD     1024  8192 32776
 :    c:  4016187        0    unused        0     0         # "raw" part, 
 : don't edit
 :    d:   131072   262160    4.2BSD     1024  8192 16392
 :    e:   131072   393232    4.2BSD     1024  8192 16392
 :    f:  1523696   524304    4.2BSD     2048 16384 28552
 : 
 : (newfs /dev/da0s1a; newfs -U /dev/da0s1d; newfs -U /dev/da0s1e; newfs -U 
 : /dev/da0s1f)
 : 
 : I have this /etc/fstab on USB flash:
 : 
 : /dev/da0s1a     /        ufs      ro,sync    1       1
 : /dev/da0s1d     /var     ufs      ro,sync    2       2
 : /dev/da0s1e     /tmp     ufs      ro,sync    2       2
 : /dev/da0s1f     /usr     ufs      ro,sync    2       2
 : 
 : Then I boot system from USB flash, and get the same result:
 : http://users.msu.dubna.ru/~shiryaev/files/fbsd/nokia020_1.jpg
 : 
 : Then I retry to boot from USB flash, and see message "Missing operating 
 : system".
 : 
 : I.e. data structure is damaged even in case of specifying "ro,sync".
 : 
 : Additional information:
 : 1. Kernel configuration: GENERIC, no CPUTYPE and CFLAGS in /etc/make.conf
 : 2. This bug does not take place in current version of DragonFlyBSD (but 
 : there other bug takes place)
 : 
 : Can somebody try to reproduce it? It can be 100% reproduced on my system.
 
 I have a usb 1.0 16MB flash that I was able to boot w/o any data
 corruption like you are seeing.  The USB 1.0 flash is quite slow, but
 works.  I have several of the USB 2.0 to SD card adapters, and none of
 them are able to boot on my laptop.  Only my ancient 1.0 job is able
 to get the job done, but it too is slow.  I was able to boot a dozen
 times w/o any data corruption.  I will admit that I used the boot
 loader off of my hard disk to select the second drive and then select
 F1 to pick the partition to boot, but since you also see this with
 grub, I'm guessing that doesn't matter much.
 
 I created it from an image of a 6.2 snapshot that we use for our
 products at work from November 10th, 2006 (so there's maybe a dozen
 changes not in it that are in 6.2-RELEASE).  I'll see if I can create
 an image for you to try (need permission to distribute).  There is one
 snag: the system hangs just before I get a login prompt, so I can't
 poke around the system after it boots.
 
 Warner