* Stanislaw Gruszka <sgruszka@redhat.com> wrote:

> When (no)bootmem finish operation, it pass pages to buddy allocator.
> Since debug_pagealloc_enabled is not set, we will do not protect pages,
> what is not what we want with CONFIG_DEBUG_PAGEALLOC=y.
> 
> To fix remove debug_pagealloc_enabled. That variable was introduced by
> commit 12d6f21e "x86: do not PSE on CONFIG_DEBUG_PAGEALLOC=y" to get
> more CPA (change page attribude) code testing. But currently we have
> CONFIG_CPA_DEBUG, which test CPA.
> 
> Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
> Acked-by: Mel Gorman <mgorman@suse.de>
> ---
>  arch/x86/mm/pageattr.c |    6 ------
>  include/linux/mm.h     |   10 ----------
>  init/main.c            |    5 -----
>  mm/debug-pagealloc.c   |    3 ---
>  4 files changed, 0 insertions(+), 24 deletions(-)

I'm getting this boot crash with the patch applied:

Initializing CPU#0
allocated 4193792 bytes of page_cgroup
please try 'cgroup_disable=memory' option if you don't want memory cgroups
Initializing HighMem for node 0 (000377fe:0003fff0)
BUG: unable to handle kernel paging request at f6fefe80
IP: [<c1621ab5>] find_range_array+0x5e/0x69
*pde = 01ff2067 *pte = 36fef160 
Oops: 0002 [#1] SMP DEBUG_PAGEALLOC
Modules linked in:

Pid: 0, comm: swapper Not tainted 3.2.0-rc4-tip-01533-g9b242f0-dirty #162987 System manufacturer System Product Name/A8N-E
EIP: 0060:[<c1621ab5>] EFLAGS: 00010046 CPU: 0
EIP is at find_range_array+0x5e/0x69
EAX: 00000000 EBX: 00000300 ECX: 00000300 EDX: f6fefe80
ESI: 00000030 EDI: f6fefe80 EBP: c15b9ed0 ESP: c15b9eb0
 DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068
Process swapper (pid: 0, ti=c15b8000 task=c15bdee0 task.ti=c15b8000)
Stack:
 377fe000 00000000 00000300 00000000 00000010 00000000 c1608c40 00000000
 c15b9f00 c1622064 c15b0020 c15c32a0 c15c32b0 c15c32a0 000377fe c15b9f1c
 00000002 c1608c40 000377fe 0003fff0 c15b9f2c c1620dd0 0003fff0 d9d9ca83
Call Trace:
 [<c1622064>] __get_free_all_memory_range+0x39/0xb4
 [<c1620dd0>] add_highpages_with_active_regions+0x18/0x9b
 [<c1621a2e>] set_highmem_pages_init+0x70/0x90
 [<c162122b>] mem_init+0x50/0x21b
 [<c1629913>] ? __alloc_bootmem_node_nopanic+0x63/0x86
 [<c13ea147>] ? printk+0x1d/0x1f
 [<c162ac6a>] ? page_cgroup_init_flatmem+0x8f/0xbc
 [<c16155bd>] start_kernel+0x1bf/0x31c
 [<c1615213>] ? obsolete_checksetup+0x95/0x95
 [<c1615065>] i386_start_kernel+0x65/0x67
Code: 00 00 c7 44 24 04 00 00 00 00 e8 e5 81 00 00 09 c2 75 0c c7 04 24 28 fc 51 c1 e8 60 84 dc ff 8d 90 00 00 00 c0 89 d9 31 c0 89 d7 <f3> aa 83 c4 18 89 d0 5b 5f 5d c3 55 89 e5 57 89 d7 56 89 c6 53 
EIP: [<c1621ab5>] find_range_array+0x5e/0x69 SS:ESP 0068:c15b9eb0
CR2: 00000000f6fefe80
---[ end trace a7919e7f17c0a725 ]---

Config and full crashlog attached.

Thanks,

	Ingo