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

From: David Daney
Date: Tue May 07 2013 - 13:27:27 EST


On 05/07/2013 09:46 AM, Jiang Liu wrote:
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.

This has caused multiple problems in the past. I wrote a patch to correct this problem, but it looks like it was never applied.

I just sent the patch to you guys as a separate e-mail.

David Daney




#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!

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