[Galaxy S II Q&A, Help & Troubleshooting] itm:
Just had another lock-up. This time the phone got quite warm, and drained from 97% battery to 11% in 1.5 hours, so something was chewing up the CPU. Here's the last_kmsg output from immediately after the reboot:

Ibl: pbl_read_emmc441() read 8k

Ibl: pbl_read_emmc441() read 96k

Ibl: pbl_read_emmc441() read download info

Ibl: pbl_read_emmc441() endop

Ibl: jump() verify_binary_integrity...ok

Ibl: jump() jump!!!

Welcome to Samsung Primitive Bootloader.

build time: May 8 2012 19:31:07

current time: f0/e/1 30:70:7c

[set_mmc_ocr] Sector Mode

[hsmmc_init] MMC card is detected

Product Name : VYL00M

<display_card_info:1009> ext_csd

<display_card_info:1011>card_size: 15028

Total Card Size: 15029 MByte

mmc_init: card initialization completed!

pbl found bootable sbl in #53248.

jump to sbl 0x4d400000.

Secondary Bootloader v3.1 version.

Copyright (C) 2011 System S/W Group. Samsung Electronics Co., Ltd.

Board: C1 REV 02 / Aug 12 2011 11:37:21

current time: f0/e/1 30:70:7d

booting code=0xc0c080c0

[set_mmc_ocr] Sector Mode

[hsmmc_init] MMC card is detected

Product Name : VYL00M

CID:150100 56594c30 304d1941 4e02a76e

<display_card_info:1040> ext_csd

<display_card_info:1042>card_size: 15028

Total Card Size: 15029 MByte

Total Sector Count: 30777344

MoviNand Initialization Complete!

===== PARTITION INFORMATION =====

ID : GANG (0x0)

DEVICE : MMC

FIRST UNIT : 0

NO. UNITS : 0

=================================

ID : BOOT (0x1)

DEVICE : MMC

FIRST UNIT : 0

NO. UNITS : 0

=================================

ID : EFS (0x4)

DEVICE : MMC

FIRST UNIT : 8192

NO. UNITS : 40960

=================================

ID : SBL1 (0x2)

DEVICE : MMC

FIRST UNIT : 49152

NO. UNITS : 2560

=================================

ID : SBL2 (0x3)

DEVICE : MMC

FIRST UNIT : 53248

NO. UNITS : 2560

=================================

ID : PARAM (0x5)

DEVICE : MMC

FIRST UNIT : 57344

NO. UNITS : 16384

=================================

ID : KERNEL (0x6)

DEVICE : MMC

FIRST UNIT : 73728

NO. UNITS : 16384

=================================

ID : RECOVERY (0x7)

DEVICE : MMC

FIRST UNIT : 90112

NO. UNITS : 16384

=================================

ID : CACHE (0x8)

DEVICE : MMC

FIRST UNIT : 106496

NO. UNITS : 204800

=================================

ID : MODEM (0x9)

DEVICE : MMC

FIRST UNIT : 311296

NO. UNITS : 32768

=================================

ID : FACTORYFS (0xa)

DEVICE : MMC

FIRST UNIT : 344064

NO. UNITS : 1048576

=================================

ID : DATAFS (0xb)

DEVICE : MMC

FIRST UNIT : 1392640

NO. UNITS : 4194304

=================================

ID : UMS (0xc)

DEVICE : MMC

FIRST UNIT : 5586944

NO. UNITS : 24133632

=================================

ID : HIDDEN (0xd)

DEVICE : MMC

FIRST UNIT : 29720576

NO. UNITS : 1048576

=================================

loke_init: j4fs_open..success

<start_checksum:1033>CHECKSUM_HEADER_SECTOR :42

<start_checksum:1035>offset:42, size:1024

Not Need Movinand Checksum

load_lfs_parameters valid magic code and version.

switch_sel_str='1'

load_debug_level: read debug level successfully(0x574f4c44)...LOW

init_ddi_data: usable ddi data.

init_fuel_gauge : not por status

fuel_gauge_get_version: [1]=0, [0]=92

init_fuel_gauge: vcell = 3670 mV, vfocv = 3785 mV, soc = 37

microusb_get_attached_device: STATUS1:0x3f, 2:0x0

microusb_get_attached_device: STATUS1:0x3f, 2:0x0

1227 = (365000 - 356525)*14484/100000

[14] 368610 = (1227 * 100000) / 32927 + 364884

init_microusb_ic: MUIC: CONTROL1:0x0

init_microusb_ic: MUIC: CONTROL1:0x0

init_microusb_ic: MUIC: CONTROL2:0x3a

init_microusb_ic: MUIC: CONTROL2:0x3a

reading nps status file is successfully!.

nps status=0x504d4f43

PMIC_IRQSRC = 0x0

PMIC_IRQ1 = 0x8b

PMIC_IRQ2 = 0x1c

PMIC_IRQ3 = 0x0

PMIC_IRQ4 = 0x11

PMIC_STATUS1 = 0x1

PMIC_STATUS2 = 0x10

PMIC_STATUS3 = 0x0

PMIC_STATUS4 = 0x0

bootloader base address=0x4d400000

LPDDR0 1st. cached=0x40000000, size=0xe400000

LPDDR0 non-cached=0x4e400000, size=0xa00000

LPDDR0 2nd. cached=0x4ee00000, size=0x1200000

RST_STAT = 0x10000

get_hwrev() = 14

board_process_platform: MAGIC c0c080c0 at 40000000!

scan_keypad_level: pressed key is 2

scan_keypad_level: pressed key is 2

scan_keypad_level: pressed key is 2

microusb_get_attached_device: STATUS1:0x3f, 2:0x0

microusb_get_attached_device: STATUS1:0x3f, 2:0x0

microusb_get_attached_device: STATUS1:0x3f, 2:0x0

microusb_get_attached_device: STATUS1:0x3f, 2:0x0

hw_pm_status: jig_status = 0, chg_status = 0

.....kernel is non signed binary.

DISPLAY_PATH_SEL[MDNIE 0x1]is on

div:2, FB_SOURCE_CLOCK:667000000, FB_PIXEL_CLOCK:25067520

MDNIE setting Init start!!

vsync interrupt is off

video interrupt is off

[fb0] turn on

MDNIE setting Init end!!

Autoboot (0 seconds) in progress, press any key to stop

boot_kernel: debug level low!

checkbit: find RECOVERY

checkbit (0)

.....kernel is non signed binary.

ATAG_CORE: 5 54410001 0 0 0

MEMCONFIG: 20e01323 20e01323

ATAG_MEM: 4 54410002 10000000 40000000

ATAG_MEM: 4 54410002 10000000 50000000

ATAG_MEM: 4 54410002 10000000 60000000

ATAG_MEM: 4 54410002 10000000 70000000

ATAG_SERIAL: 4 54410006 4e02a76e 304d1941

ATAG_REVISION: 3 54410007 e

ATAG_CMDLINE: 37 54410009 'loglevel=4 console=ram sec_debug.enable=0 sec_debug.enable_user=0 c1_watchdog.sec_pet=5 sec_log=0x100000@0x4d900000 s3cfb.bootloaderfb=0x5ec00000 ld9040.get_lcdtype=0x0 consoleblank=0 lpj=3981312 vmalloc=144m'

ATAG_NONE: 0 0

Starting kernel at 0x40008000...