Hi Lv,

Do you have any idea with this old WARNING? It's still occurring in
linux-next.

[    0.000000] ACPI: Early table checksum verification disabled
[    0.000000] ACPI: RSDP 0x00000000000F0CF0 000014 (v00 BOCHS )
[    0.000000] ------------[ cut here ]------------
[    0.000000] WARNING: CPU: 0 PID: 0 at mm/early_ioremap.c:136 __early_ioremap+0x2c0/0x55a()
[    0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 3.16.0-wl-ath-02337-gfa3c32b #472
[    0.000000] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.7.5-20140531_083030-gandalf 04/01/2014
[    0.000000]  0000000000000009 ffffffff91203d30 ffffffff900f79e1 ffffffff91203d68
[    0.000000]  ffffffff8e2df444 0000000000000001 8000000000000563 0000000000000000
[    0.000000]  00000000ea4edd58 0000000000000000 ffffffff91203d78 ffffffff8e2df58f
[    0.000000] Call Trace:
[    0.000000]  [<ffffffff900f79e1>] dump_stack+0x2e/0x3e
[    0.000000]  [<ffffffff8e2df444>] warn_slowpath_common+0xb3/0xe5
[    0.000000]  [<ffffffff8e2df58f>] warn_slowpath_null+0x25/0x2f
[    0.000000]  [<ffffffff925d7908>] __early_ioremap+0x2c0/0x55a
[    0.000000]  [<ffffffff925d8138>] early_ioremap+0x1a/0x23
[    0.000000]  [<ffffffff925ad694>] __acpi_map_table+0x60/0x6e
[    0.000000]  [<ffffffff900d4b70>] acpi_os_map_iomem+0x46/0x30f
[    0.000000]  [<ffffffff900d4e49>] acpi_os_map_memory+0x10/0x19
[    0.000000]  [<ffffffff92615a51>] acpi_tb_parse_root_table+0x203/0x40f
[    0.000000]  [<ffffffff92615d55>] acpi_initialize_tables+0xf8/0x105
[    0.000000]  [<ffffffff926123e7>] acpi_table_init+0x7f/0x174
[    0.000000]  [<ffffffff925ae021>] acpi_boot_table_init+0x4e/0x15c
[    0.000000]  [<ffffffff9259e4b9>] setup_arch+0x110c/0x1382
[    0.000000]  [<ffffffff92597120>] ? early_idt_handlers+0x120/0x120
[    0.000000]  [<ffffffff92598525>] start_kernel+0xe6/0x9c7
[    0.000000]  [<ffffffff92597120>] ? early_idt_handlers+0x120/0x120
[    0.000000]  [<ffffffff9259777a>] x86_64_start_reservations+0x64/0x6d
[    0.000000]  [<ffffffff92597970>] x86_64_start_kernel+0x1ed/0x203
[    0.000000] ---[ end trace d83042b019c2cfba ]---
[    0.000000] kvm-clock: Using msrs 4b564d01 and 4b564d00

git bisect  bad fa3c32b9a48d3333d491ad8d1b24cbf8f9c452ca  # 20:39      0-     10  0day head guard for 'devel-hourly-2014081417'
git bisect  bad 19583ca584d6f574384e17fe7613dfaeadcdc4a6  # 20:49      7-     13  Linux 3.16
git bisect  bad 19583ca584d6f574384e17fe7613dfaeadcdc4a6  # 20:49      0-     13  Linux 3.16
git bisect  bad 1860e379875dfe7271c649058aeddffe5afd9d0d  # 20:57      0-      9  Linux 3.15
git bisect  bad 455c6fdbd219161bd09b1165f11699d6d73de11c  # 21:07      0-      1  Linux 3.14
git bisect  bad d8ec26d7f8287f5788a494f56e8814210f0e64be  # 21:25      1-     27  Linux 3.13
git bisect  bad 5e01dc7b26d9f24f39abace5da98ccbd6a5ceb52  # 21:37      5-     15  Linux 3.12
git bisect  bad 6e4664525b1db28f8c4e1130957f70a94c19213e  # 21:52      1-     18  Linux 3.11
git bisect  bad 8bb495e3f02401ee6f76d1b1d77f3ac9f079e376  # 21:58      0-     21  Linux 3.10
git bisect  bad c1be5a5b1b355d40e6cf79cc979eb66dafa24ad1  # 22:03      0-     19  Linux 3.9
git bisect  bad 19f949f52599ba7c3f67a5897ac6be14bfcb1200  # 22:14      0-      6  Linux 3.8
git bisect  bad 29594404d7fe73cd80eaa4ee8c43dcc53970c60e  # 22:31      0-      1  Linux 3.7
git bisect  bad a0d271cbfed1dd50278c6b06bead3d00ba0a88f9  # 22:36      0-      4  Linux 3.6
git bisect  bad 28a33cbc24e4256c143dce96c7d93bf423229f92  # 23:24      0-      9  Linux 3.5
git bisect  bad 76e10d158efb6d4516018846f60c2ab5501900bc  # 23:31      0-      1  Linux 3.4
git bisect  bad c16fa4f2ad19908a47c63d8fa436a1178438c7e7  # 23:35      1-      2  Linux 3.3
git bisect  bad 805a6af8dba5dfdd35ec35dc52ec0122400b2610  # 23:39     15-     31  Linux 3.2
git bisect  bad c3b92c8787367a8bb53d57d9789b558f1295cc96  # 23:42      0-      3  Linux 3.1
git bisect  bad 02f8c6aee8df3cdc935e9bdd4f2d020306035dbe  # 23:47      0-      9  Linux 3.0
git bisect  bad 61c4f2c81c61f73549928dfd9f3e8f26aa36a8cf  # 23:55      0-      6  Linux 2.6.39
git bisect  bad 521cb40b0c44418a4fd36dc633f575813d59a43d  # 00:08      2-      4  Linux 2.6.38
git bisect  bad 3c0eee3fe6a3a1c745379547c7e7c904aa64f6d5  # 00:12      0-     78  Linux 2.6.37
git bisect  bad f6f94e2ab1b33f0082ac22d71f66385a60d8157f  # 00:18      0-      2  Linux 2.6.36
git bisect  bad c9d26423e56ce1ab4d786f92aebecf859d419293  # 01:55      0-      2  Merge tag 'pm+acpi-3.17-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
git bisect  bad 7bef919141fc53b780070a0aec3ddd893eeece8f  # 02:33      2-      3  Add linux-next specific files for 20140815


This script may reproduce the error.

----------------------------------------------------------------------------
#!/bin/bash

kernel=$1

kvm=(
	qemu-system-x86_64
	-cpu kvm64
	-enable-kvm
	-kernel $kernel
	-m 320
	-smp 1
	-net nic,vlan=1,model=e1000
	-net user,vlan=1
	-boot order=nc
	-no-reboot
	-watchdog i6300esb
	-rtc base=localtime
	-serial stdio
	-display none
	-monitor null 
)

append=(
	hung_task_panic=1
	earlyprintk=ttyS0,115200
	debug
	apic=debug
	sysrq_always_enabled
	rcupdate.rcu_cpu_stall_timeout=100
	panic=10
	softlockup_panic=1
	nmi_watchdog=panic
	load_ramdisk=2
	prompt_ramdisk=0
	console=ttyS0,115200
	console=tty0
	vga=normal
	root=/dev/ram0
	rw
	drbd.minor_count=8
)

"${kvm[@]}" --append "${append[*]}"
----------------------------------------------------------------------------

Thanks,
Fengguang