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From: Chen Gang <chengang@emindsoft.com.cn>
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Date: Mon, 21 Dec 2015 10:47:29 +0800
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Subject: Re: [Qemu-devel] [PATCH] linux-user/syscall.c: Notice about lock
 bitmask translation for fcntl
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To: Laurent Vivier <laurent@vivier.eu>, riku.voipio@iki.fi
Cc: Peter Maydell <peter.maydell@linaro.org>, qemu-devel <qemu-devel@nongnu.org>, Richard Henderson <rth@twiddle.net>


On 2015年12月18日 18:47, Chen Gang wrote:
> 
> On 2015年12月18日 17:41, Laurent Vivier wrote:
>>
>> Le 18/12/2015 07:51, Chen Gang a écrit :

[...]

>>>
>>> +++ b/linux-user/mmap.c
>>> @@ -567,6 +567,10 @@ abi_long target_mmap(abi_ulong start, abi_ulong len, int prot,
>>>      printf("\n");
>>>  #endif
>>>      tb_invalidate_phys_range(start, start + len);
>>> +    if ((prot & PROT_WRITE) && (flags & MAP_ANONYMOUS)
>>> +        && ((flags & MAP_PRIVATE) || (fd == -1))) {
>>> +        memset(g2h(start), 0, len);
>>> +    }
>>
>> IMHO, their kernel needs a fix, mmap(2):
>>
>> MAP_ANONYMOUS
>>         The mapping is not backed by any file; its contents are initial‐
>>         ized to zero.
>>

Oh, sorry, after check again, it is not kernel's issue: mmap() will
always zero the ANONYMOUS memory for kernel 3.8 in sw_64 arch.

It is still our qemu's issue in mmap_frag (do not zero ANONYMOUS memory
fragments), so I sent patch v2 for it, please help check.

Thanks.

> 
> OK, Thanks.
> 
> 

-- 
Chen Gang (陈刚)

Open, share, and attitude like air, water, and life which God blessed