Re: Live CD problems.

["Max Herrgaard" <herrgaard@xxxxxxxxx>]

>     That is definitely not correct.  If you don't mind burning another dead
>     CD could you please try this patch?  It will force the system to panic
>     when it tries to do a 0-length I/O.  Then get a backtrace from the DDB
>     prompt so we can see the call chain that leads up to the problem.
>
>                                         -Matt

Is this sufficient?

(kgdb) bt
#0  dumpsys () at thread.h:83
#1  0xc02eb11b in boot (howto=260) at /usr/src/sys/kern/kern_shutdown.c:371
#2  0xc02eb8a4 in panic (fmt=0xc0562c05 "from debugger") at
/usr/src/sys/kern/kern_shutdown.c:796
#3  0xc0166a66 in db_panic (addr=-1068477435, have_addr=0, count=-1,
modif=0xc07d6604 "") at /usr/src/sys/ddb/db_command.c:447
#4  0xc01669fb in db_command (last_cmdp=0xc0634690, cmd_table=0x0,
aux_cmd_tablep=0xc05be6f8, aux_cmd_tablep_end=0xc05be714) at
/usr/src/sys/ddb/db_command.c:343
#5  0xc0166adb in db_command_loop () at /usr/src/sys/ddb/db_command.c:469
#6  0xc0169670 in db_trap (type=3, code=0) at /usr/src/sys/ddb/db_trap.c:71
#7  0xc05050a8 in kdb_trap (type=3, code=0, regs=0xc07d6728) at
/usr/src/sys/platform/pc32/i386/db_interface.c:148
#8  0xc0517f20 in trap (frame=0xc07d6728) at
/usr/src/sys/platform/pc32/i386/trap.c:804
#9  0xc05060f6 in calltrap () at /usr/src/sys/platform/pc32/i386/exception.s:783
#10 0xc0505405 in Debugger (msg=0x12 <Address 0x12 out of bounds>) at
cpufunc.h:73
#11 0xc02eb89c in panic (fmt=0xc05652e4 "zero length DMA transfer") at
/usr/src/sys/kern/kern_shutdown.c:794
#12 0xc01a04c8 in ata_dmaload (dev=0xc622bb28, data=0xc0c14000 "",
count=0, dir=2, addr=0x12, entries=0x0) at
/usr/src/sys/dev/disk/nata/ata-dma.c:230
#13 0xc01a0ca0 in ata_begin_transaction (request=0xc0b2b190) at
/usr/src/sys/dev/disk/nata/ata-lowlevel.c:180
#14 0xc01a4710 in ata_start (dev=0xc622bb28) at
/usr/src/sys/dev/disk/nata/ata-queue.c:214
#15 0xc01a4376 in ata_queue_request (request=0xc0b2b190) at
/usr/src/sys/dev/disk/nata/ata-queue.c:95
#16 0xc01b386d in atapi_action (sim=0xc0b03ba8, ccb=0x0) at
/usr/src/sys/dev/disk/nata/atapi-cam.c:602
#17 0xc014be68 in xpt_run_dev_sendq (bus=0xc0af2c90) at
/usr/src/sys/bus/cam/cam_xpt.c:3640
#18 0xc014b111 in xpt_action (start_ccb=0xca67a140) at
/usr/src/sys/bus/cam/cam_xpt.c:2809
#19 0xc015c90b in cdstart (periph=0xc0b03bf8, start_ccb=0xca67a140) at
/usr/src/sys/bus/cam/scsi/scsi_cd.c:1584
#20 0xc014bbfc in xpt_run_dev_allocq (bus=0xc0af2c90) at
/usr/src/sys/bus/cam/cam_xpt.c:3507
#21 0xc014baa1 in xpt_schedule (perph=0xc0b03bf8,
new_priority=3232705680) at /usr/src/sys/bus/cam/cam_xpt.c:3402
#22 0xc015c5d2 in cdstrategy (ap=0x12) at
/usr/src/sys/bus/cam/scsi/scsi_cd.c:1496
#23 0xc02d456d in dev_dstrategy (dev=0xc0b25fe8, bio=0x20) at
/usr/src/sys/kern/kern_device.c:238
#24 0xc030094e in diskstrategy (ap=0x12) at /usr/src/sys/kern/subr_disk.c:423
#25 0xc02d456d in dev_dstrategy (dev=0xc0b26f18, bio=0x20) at
/usr/src/sys/kern/kern_device.c:238
#26 0xc034824d in spec_strategy (ap=0xc65f5d18) at
/usr/src/sys/vfs/specfs/spec_vnops.c:544
#27 0xc034328b in vop_strategy (ops=0x0, vp=0xc0b6b188,
bio=0xc0ba3e30) at /usr/src/sys/kern/vfs_vopops.c:659
#28 0xc0329357 in vn_strategy (vp=0xc0b6b188, bio=0x20) at
/usr/src/sys/kern/vfs_bio.c:2779
#29 0xc0326140 in bread (vp=0xc0b6b188, loffset=) at
/usr/src/sys/kern/vfs_bio.c:630
#30 0xc02c2f4e in iso_mountfs (devvp=0xc0b6b188, mp=0xc0b84020,
argp=0xc07d6b64) at /usr/src/sys/vfs/isofs/cd9660/cd9660_vfsops.c:321
#31 0xc02c2ad8 in iso_mountroot (mp=0xc0b84020) at
/usr/src/sys/vfs/isofs/cd9660/cd9660_vfsops.c:165
#32 0xc02c2b36 in cd9660_mount (mp=0xc0b84020, path=0x0, data=0x12
<Address 0x12 out of bounds>, cred=0xc0b16120) at
/usr/src/sys/vfs/isofs/cd9660/cd9660_vfsops.c:189
#33 0xc032f650 in vfs_mountroot_try (mountfrom=0xc0577e53
"cd9660:cd0c") at /usr/src/sys/kern/vfs_conf.c:244
#34 0xc032f3f4 in vfs_mountroot (junk=0x0) at /usr/src/sys/kern/vfs_conf.c:143
#35 0xc02c7cd1 in mi_startup () at /usr/src/sys/kern/init_main.c:234
#36 0xc014098b in begin () at /usr/src/sys/platform/pc32/i386/locore.s:337