Philippe Waroquiers 6fe6c23808 Finally understood why an outer on inner on a 32 bit application ...

is failing on a 64 bit host.

The bug might or might not be related to some
errors "failed in UME with error 22"
(such as bug https://bugs.kde.org/show_bug.cgi?id=138424).

The bug is: when aspacem_maxAddr is very close to the upper limit,
and aspacem_minAddr is somewhat not close to 0, then
the computation of  
   aspacem_vStart = VG_PGROUNDUP((aspacem_minAddr + aspacem_maxAddr + 1) / 2);
can overflow.
The vStart value will then silently wrap around.
(please, give me my Ada language back :).

When overflowing, vStart will then be below the client cStart.
At least when running outer on inner on a 32 bit application on
a 64 bit system, this was causing strange problems.

I suppose that on a 64 bit system, a 32 bit application can use more
of the 4 Gb, and then the max address is higher and can more easily
overflow than on a 32 bit system.

Tested on f12/x86, debian6/amd64 (bi-arch).
+ run a few outer on inner x86 regression tests : these were all failing
and are now succesfully running.



git-svn-id: svn://svn.valgrind.org/valgrind/trunk@12438

2012-03-08 23:42:05 +00:00

..

aspacemgr-common.c

Update all copyright dates, from 20xy-2010 to 20xy-2011.

2011-10-23 07:32:08 +00:00

aspacemgr-linux.c

Finally understood why an outer on inner on a 32 bit application

2012-03-08 23:42:05 +00:00

priv_aspacemgr.h

Update all copyright dates, from 20xy-2010 to 20xy-2011.

2011-10-23 07:32:08 +00:00