mmap for /proc/vmcore broken since 3.12-rc1

[HATAYAMA Daisuke]

(2013/10/02 21:03), Michael Holzheu wrote:
> Hello Alexey,
>
> Looks like the following commit broke mmap for /proc/vmcore:
>
> commit c4fe24485729fc2cbff324c111e67a1cc2f9adea
> Author: Alexey Dobriyan <adobriyan at gmail.com>
> Date:   Tue Aug 20 22:17:24 2013 +0300
>
>      sparc: fix PCI device proc file mmap(2)
>
> Because /proc/vmcore (fs/proc/vmcore.c) does not implement the
> get_unmapped_area() fops function mmap now always returns EIO.
>
> Michael
>

I confirmed the bug on v3.12-rc3. According to makedumpfile's log,
mmap failed on /proc/vmcore.

mem_map (271)
   mem_map    : ffffea001da40000
   pfn_start  : 878000
   pfn_end    : 880000
Kernel can't mmap vmcore, using reads.
STEP [Excluding unnecessary pages] : 1.268799 seconds
STEP [Excluding unnecessary pages] : 1.268756 seconds
STEP [Copying data               ] : 44.847924 seconds
Writing erase info...

I'll post a patch later.

-- 
Thanks.
HATAYAMA, Daisuke