[DiskUsage] Segment violation while navigating after 2 scans of a large partition

[oco]

The partition contains lot of files (> 500000) and was mounted ReadOnly (source trees).

It was in revision hrev42926.

Here is the gdb output :

Thread 330 caused an exception: Segment violation
[...]
[Switching to team /boot/system/apps/DiskUsage (326) thread w>DiskUsage (330)]
0x0021760e in PieView::_DrawDirectory ()
(gdb) bt
#0  0x0021760e in PieView::_DrawDirectory ()
#1  0x002165d7 in PieView::_DrawPieChart ()
#2  0x00215f08 in PieView::Draw ()
#3  0x003c5ae0 in BView::_Draw () from /boot/system/lib/libbe.so
#4  0x003caf11 in BWindow::DispatchMessage () from /boot/system/lib/libbe.so
#5  0x003cf544 in BWindow::task_looper () from /boot/system/lib/libbe.so
#6  0x002fb117 in BLooper::_task0_ () from /boot/system/lib/libbe.so
#7  0x0057d95f in thread_entry () from /boot/system/lib/libroot.so
#8  0x78033fec in ?? ()