[PATCH v8 9/9] vmcore: support mmap() on /proc/vmcore
d.hatayama at jp.fujitsu.com
Sun May 26 21:49:27 EDT 2013
(2013/05/24 18:02), Maxim Uvarov wrote:
> 2013/5/24 Andrew Morton <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>> 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.
Thanks! That's very helpful.
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