Re: [Valgrind-users] UME Error 22

[Wan M. F. W. I. <wan...@mc...>]

Hi,
x0152532@unx0152532:~/mydroid$ readelf -l ./linker

Elf file type is EXEC (Executable file)
Entry point 0xb0001000
There are 5 program headers, starting at offset 52

Program Headers:
  Type           Offset   VirtAddr   PhysAddr   FileSiz MemSiz  Flg Align
  LOAD           0x0000d4 0x00000000 0xb0000000 0x00000 0x00000 R   0x1000
  LOAD           0x001000 0xb0001000 0xb0001000 0x073bc 0x073bc R E 0x1000
  LOAD           0x009000 0xb0009000 0xb0009000 0x0068c 0x0969c RW  0x1000
  GNU_STACK      0x000000 0x00000000 0x00000000 0x00000 0x00000 RW  0
  EXIDX          0x008004 0xb0008004 0xb0008004 0x003b8 0x003b8 R   0x4

 Section to Segment mapping:
  Segment Sections...
   00
   01     .text .rodata .ARM.extab .ARM.exidx
   02     .preinit_array .init_array .fini_array .ctors .data.rel.ro .got
.data .bss
   03
   04     .ARM.exidx


Here you are. Thanks.


On Tue, May 3, 2011 at 3:22 PM, Tom Hughes <to...@co...> wrote:

> On 03/05/11 14:07, Wan Mohd Fairuz Wan Ismail wrote:
>
> > The situation:
> > The function load_ELF (elf.c) will try to load the executable and the
> > interpreter to the memory. For android's /system/bin/linker, the
> > calculated interp_size value is 2952865436.
> >
> > The formula end = (iph->p_vaddr - interp_addr) + iph->p_memsz;  gives
> > us 0xb001269c = (0xb0009000 - 0x0) + 0x969c  so that's why we have
> > interp_size as big as 2.9GB. So I tried to do interp_size = end &
> > 0xFFFFF.. There is no more UME 22 Error but I got a Segmentation fault
> > (the program works fine alone).
>
> Basically valgrind is trying to cheat, and instead of mapping each LOAD
> segment in the ELF file separately it is trying to map one block of
> contiguous memory and then load each segment at the correct offset in
> that block.
>
> Unfortunately it seems that the Android interpreter is linked in such a
> way that the load segments are a long way apart, so it winds up trying
> to allocate a very large block of memory, most of which won't be used.
>
> If you can run readelf then try "readelf -l /system/bin/linker" and let
> us see the output - you may have to copy the linker off onto a
> conventional system and run readelf there.
>
> Tom
>
> --
> Tom Hughes (to...@co...)
> http://compton.nu/
>



-- 
Wan Mohd Fairuz WAN ISMAIL
OMAP System Multimedia Integration Team (Trainee)
Texas Instrument France
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