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Re: [Qemu-devel] [PATCH] linux-user/syscall.c: Notice about lock bitmask
From: |
Chen Gang |
Subject: |
Re: [Qemu-devel] [PATCH] linux-user/syscall.c: Notice about lock bitmask translation for fcntl |
Date: |
Mon, 21 Dec 2015 10:47:29 +0800 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.4.0 |
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