start_kernel(): bug: interrupts were enabled early

[Rabin Vincent <rabin@rab.in>]

On latest git, I'm seeing "start_kernel(): bug: interrupts were enabled
early" messages on ARM (sample log below).

This appears to be caused by:

  start_kernel -> radix_tree_init -> kmem_cache_create (slub) ->
   down_write -> __down_write (lib/rwsem-spinlock.c) -> spin_unlock_irq

radix_tree_init was moved earlier by:

  commit 773e3eb7b81e5ba13b5155dfb3bb75b8ce37f8f9
  Author: Yinghai Lu <yinghai@kernel.org>
  Date:   Wed Feb 10 01:20:33 2010 -0800

      init: Move radix_tree_init() early

      Prepare for using radix trees in early_irq_init().

      Signed-off-by: Yinghai Lu <yinghai@kernel.org>
      LKML-Reference: <1265793639-15071-30-git-send-email-yinghai@kernel.org>
      Signed-off-by: H. Peter Anvin <hpa@zytor.com>

Rabin

---
Uncompressing Linux... done, booting the kernel.
Linux version 2.6.34-rc2-00184-g01e7770 (rabin@debian) (gcc version 4.4.1 (Sourcery G++ Lite 2009q3-67) ) #5 Fri Mar 26 00:56:33 IST 2010
CPU: ARMv7 Processor [410fc080] revision 0 (ARMv7), cr=10c03c7f
CPU: VIPT nonaliasing data cache, VIPT nonaliasing instruction cache
Machine: ARM-RealView PB-A8
Ignoring unrecognised tag 0x00000000
bootconsole [earlycon0] enabled
Memory policy: ECC disabled, Data cache writeback
Built 1 zonelists in Zone order, mobility grouping on.  Total pages: 32512
Kernel command line: earlyprintk mem=128M console=ttyAMA0 root=/dev/ram0 init=/linuxrc
PID hash table entries: 512 (order: -1, 2048 bytes)
Dentry cache hash table entries: 16384 (order: 4, 65536 bytes)
Inode-cache hash table entries: 8192 (order: 3, 32768 bytes)
Memory: 128MB = 128MB total
Memory: 123916k/123916k available, 7156k reserved, 0K highmem
Virtual kernel memory layout:
    vector  : 0xffff0000 - 0xffff1000   (   4 kB)
    fixmap  : 0xfff00000 - 0xfffe0000   ( 896 kB)
    DMA     : 0xffc00000 - 0xffe00000   (   2 MB)
    vmalloc : 0xc8800000 - 0xf8000000   ( 760 MB)
    lowmem  : 0xc0000000 - 0xc8000000   ( 128 MB)
    modules : 0xbf000000 - 0xc0000000   (  16 MB)
      .init : 0xc0008000 - 0xc0331000   (3236 kB)
      .text : 0xc0331000 - 0xc040b000   ( 872 kB)
      .data : 0xc040c000 - 0xc0418180   (  49 kB)
SLUB: Genslabs=11, HWalign=32, Order=0-3, MinObjects=0, CPUs=1, Nodes=1
Hierarchical RCU implementation.
RCU-based detection of stalled CPUs is enabled.
NR_IRQS:96
start_kernel(): bug: interrupts were enabled early
Calibrating delay loop... 419.43 BogoMIPS (lpj=2097152)
Mount-cache hash table entries: 512
CPU: Testing write buffer coherency: ok
devtmpfs: initialized
Serial: AMBA PL011 UART driver
dev:uart0: ttyAMA0 at MMIO 0x10009000 (irq = 44) is a AMBA/PL011
console [ttyAMA0] enabled, bootconsole disabled
console [ttyAMA0] enabled, bootconsole disabled
dev:uart1: ttyAMA1 at MMIO 0x1000a000 (irq = 45) is a AMBA/PL011
dev:uart2: ttyAMA2 at MMIO 0x1000b000 (irq = 46) is a AMBA/PL011
fpga:uart3: ttyAMA3 at MMIO 0x1000c000 (irq = 47) is a AMBA/PL011
Switching to clocksource timer3
Unpacking initramfs...
Freeing initrd memory: 1680K
VFP support v0.3: implementor 41 architecture 3 part 30 variant c rev 0
Freeing init memory: 3236K