Re: MIPS : die at free_initmem() function 3.9+

From: Jiang Liu
Date: Tue May 07 2013 - 12:46:55 EST


Hi Eunsong,
Thanks for your help. I have done some code inspection and have
found a possible reason for this issue. It seems that virt_to_page()
can't be used to handle address in compatible segments due to following
definitions.

#define virt_to_page(kaddr) pfn_to_page(PFN_DOWN(virt_to_phys(kaddr)))
static inline unsigned long virt_to_phys(volatile const void *address)
{
return (unsigned long)address - PAGE_OFFSET + PHYS_OFFSET;
}
#define __va(x) ((void *)((unsigned long)(x) + PAGE_OFFSET - PHYS_OFFSET))
#define __pa_symbol(x) __pa(RELOC_HIDE((unsigned long)(x), 0))
#define __pa(x) \
({ \
unsigned long __x = (unsigned long)(x); \
__x < CKSEG0 ? XPHYSADDR(__x) : CPHYSADDR(__x); \
})

#define CPHYSADDR(a) ((_ACAST32_(a)) & 0x1fffffff)
#define XPHYSADDR(a) ((_ACAST64_(a)) & \
_CONST64_(0x000000ffffffffff))

#define XKUSEG _CONST64_(0x0000000000000000)
#define XKSSEG _CONST64_(0x4000000000000000)
#define XKPHYS _CONST64_(0x8000000000000000)
#define XKSEG _CONST64_(0xc000000000000000)
#define CKSEG0 _CONST64_(0xffffffff80000000)
#define CKSEG1 _CONST64_(0xffffffffa0000000)
#define CKSSEG _CONST64_(0xffffffffc0000000)
#define CKSEG3 _CONST64_(0xffffffffe0000000)

So could you please help to prepare a formal patch for this bug and send
it to Andrew Morton for v3.10-rc1? Otherwise I could help to it too.

Regards!
Gerry


=On 05/06/2013 06:39 AM, EUNBONG SONG wrote:
>
>> So on 64bits MIPS platforms, __va(__pa(x)) may not equal to x, that may cause
>> trouble to free_initmem_default(). Could you please help to do another test
>> by changing
>> free_initmem_default(POISON_FREE_INITMEM);
>> to
>> free_initmem_default(0);
>
>> This test could help to identify whether this panic is caused by
>> memset((void *)pos, poison, PAGE_SIZE);
>> in function free_reserved_area().
>
> Hello, as you said i changed "free_initmem_default(POISON_FREE_INITMEM);" to
> "free_initmem_default(0);". Panic still occurred.
> Actually, i put the some debug messages. and i confirmed panic occurs in __free_reserved_page() function.
> Thanks!
>
> NëêïríyéìbìÐívï^ï)é{.nï+ëì{ìåzXãìè}ìêìï&j:+vëïìåzZ+ï+zfïíìï~ëëiïézïìâï?ìéï&ï)åfë^jíyìë@Aìëïï 0ëhïïiï
>

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/