[PATCH v8 9/9] vmcore: support mmap() on /proc/vmcore

Zhang Yanfei zhangyanfei at cn.fujitsu.com
Thu May 30 05:26:33 EDT 2013


On 05/30/2013 05:14 PM, Maxim Uvarov wrote:
> 
> 
> 
> 2013/5/27 HATAYAMA Daisuke <d.hatayama at jp.fujitsu.com <mailto:d.hatayama at jp.fujitsu.com>>
> 
>     (2013/05/24 18:02), Maxim Uvarov wrote:
> 
> 
> 
> 
>         2013/5/24 Andrew Morton <akpm at linux-foundation.org <mailto:akpm at linux-foundation.org> <mailto:akpm at linux-foundation.__org <mailto:akpm at linux-foundation.org>>>
> 
> 
>             On Thu, 23 May 2013 14:25:48 +0900 HATAYAMA Daisuke <d.hatayama at jp.fujitsu.com <mailto:d.hatayama at jp.fujitsu.com> <mailto:d.hatayama at jp.fujitsu.__com <mailto:d.hatayama at jp.fujitsu.com>>> wrote:
> 
>              > This patch introduces mmap_vmcore().
>              >
>              > Don't permit writable nor executable mapping even with mprotect()
>              > because this mmap() is aimed at reading crash dump memory.
>              > Non-writable mapping is also requirement of remap_pfn_range() when
>              > mapping linear pages on non-consecutive physical pages; see
>              > is_cow_mapping().
>              >
>              > Set VM_MIXEDMAP flag to remap memory by remap_pfn_range and by
>              > remap_vmalloc_range_pertial at the same time for a single
>              > vma. do_munmap() can correctly clean partially remapped vma with two
>              > functions in abnormal case. See zap_pte_range(), vm_normal_page() and
>              > their comments for details.
>              >
>              > On x86-32 PAE kernels, mmap() supports at most 16TB memory only. This
>              > limitation comes from the fact that the third argument of
>              > remap_pfn_range(), pfn, is of 32-bit length on x86-32: unsigned long.
> 
>             More reviewing and testing, please.
> 
> 
>         Do you have git pull for both kernel and userland changes? I would like to do some more testing on my machines.
> 
>         Maxim.
> 
> 
>     Thanks! That's very helpful.
> 
>     -- 
>     Thanks.
>     HATAYAMA, Daisuke
> 
> Any update for this? Where can I checkout all sources?

This series is now in Andrew Morton's -mm tree.

-- 
Thanks.
Zhang Yanfei



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