Re: BUG: Bad page state in process swapper pfn:00000

[Grant Likely <grant.likely@linaro.org>]

On Thu, Jun 12, 2014 at 3:51 AM, Laura Abbott <lauraa@codeaurora.org> wrote:
> On 6/11/2014 12:19 PM, Geert Uytterhoeven wrote:
>> Hi Laura,
>>
>> On Wed, Jun 11, 2014 at 7:32 PM, Laura Abbott <lauraa@codeaurora.org> wrote:
>>> On 6/11/2014 4:40 AM, Geert Uytterhoeven wrote:
>>>> With current mainline, I get an early crash on r8a7791/koelsch:
>>>>
>>>> BUG: Bad page state in process swapper  pfn:00000
>>>> page:ee20b000 count:0 mapcount:0 mapping:66756200 index:0x65726566
>>>> page flags: 0x74656b63(locked|error|lru|active|owner_priv_1|arch_1|private|writeback|head|swapcache
>>>> |reclaim|mlocked)
>>>> page dumped because: PAGE_FLAGS_CHECK_AT_FREE flag(s) set
>>>> bad because of flags:
>>>> page flags: 0x212861(locked|lru|active|private|writeback|swapcache|mlocked)
>>>>
>>>> I bisected it to
>>>>
>>>> commit 1c2f87c22566cd057bc8cde10c37ae9da1a1bb76
>>>> Author: Laura Abbott <lauraa@codeaurora.org>
>>>> Date:   Sun Apr 13 22:54:58 2014 +0100
>>>>
>>>>     ARM: 8025/1: Get rid of meminfo
>>
>>>> -Truncating RAM at 40000000-bfffffff to -6f7fffff (vmalloc region overlap).
>>>> +Truncating RAM at 0x00000000-0xc0000000 to -0x6f800000
>>>
>>> I'm guessing this is the issue right there.
>>>
>>>         memory@40000000 {
>>>                 device_type = "memory";
>>>                 reg = <0 0x40000000 0 0x40000000>;
>>>         };
>>>
>>>         memory@200000000 {
>>>                 device_type = "memory";
>>>                 reg = <2 0x00000000 0 0x40000000>;
>>>         };
>>>
>>> Those are the memory nodes from r8a7791-koelsch.dts. It looks like the memory
>>> outside 32-bit address range is not being dropped. It was suggested to drop
>>> early_init_dt_add_memory_arch which called arm_add_memory and just use the
>>> generic of code directly but the problem is arm_add_memory does additional
>>> bounds checking. It looks like early_init_dt_add_memory_arch in
>>> drivers/of/fdt.c checks for overflow on u64 types but not for overflow
>>> on phys_addr_t (32 bits) which is what memblock_add actually uses.
>>>
>>> For a quick test, can you try bringing back early_init_dt_add_memory_arch
>>> and see if that fixes the problem:
>>>
>>> diff --git a/arch/arm/kernel/devtree.c b/arch/arm/kernel/devtree.c
>>> index e94a157..ea9ce92 100644
>>> --- a/arch/arm/kernel/devtree.c
>>> +++ b/arch/arm/kernel/devtree.c
>>> @@ -27,6 +27,10 @@
>>>  #include <asm/mach/arch.h>
>>>  #include <asm/mach-types.h>
>>>
>>> +void __init early_init_dt_add_memory_arch(u64 base, u64 size)
>>> +{
>>> +       arm_add_memory(base, size);
>>> +}
>>>
>>>  #ifdef CONFIG_SMP
>>>  extern struct of_cpu_method __cpu_method_of_table[];
>>
>> Thanks, my board boots again after applying this quick hack.
>>
>
> Great! Russell are you okay with taking the above as a fix or would you prefer
> I fixup drivers/of/fdt.c right now?

I would rather see the fix directly in fdt.c.

g.

>
>
> Thanks,
> Laura
>
> ----8<----
> From 14bda557a108ad197e7c5f040f50ca024b45cc17 Mon Sep 17 00:00:00 2001
> From: Laura Abbott <lauraa@codeaurora.org>
> Date: Wed, 11 Jun 2014 19:39:29 -0700
> Subject: [PATCH] arm: Bring back early_init_dt_add_memory_arch
>
> Commit 1c2f87c (ARM: 8025/1: Get rid of meminfo) removed
> early_init_dt_add_memory_arch in favor of using the common method.
> The common method does not currently check for memory outside of
> 32-bit bounds which may lead to memory being incorrectly added to
> the system. Bring back early_init_dt_add_memory_arch for now until
> the generic function can be fixed up.
>
> Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
> Signed-off-by: Laura Abbott <lauraa@codeaurora.org>
> ---
>  arch/arm/kernel/devtree.c | 4 ++++
>  1 file changed, 4 insertions(+)
>
> diff --git a/arch/arm/kernel/devtree.c b/arch/arm/kernel/devtree.c
> index e94a157..ea9ce92 100644
> --- a/arch/arm/kernel/devtree.c
> +++ b/arch/arm/kernel/devtree.c
> @@ -27,6 +27,10 @@
>  #include <asm/mach/arch.h>
>  #include <asm/mach-types.h>
>
> +void __init early_init_dt_add_memory_arch(u64 base, u64 size)
> +{
> +       arm_add_memory(base, size);
> +}
>
>  #ifdef CONFIG_SMP
>  extern struct of_cpu_method __cpu_method_of_table[];
> --
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