> In 1999 when I was using Linux, gdb could give backtraces into dlopen()ed
> code, but it could not set breakpoints in it.  I don't think it could step
> into it either, but I am not sure.

Both are normally done by writing to the code segment.
If it is mapped shared then you are in trouble!
OTOH dlopen() seems to to:

 685 mozilla-bin CALL  mmap(         0,0x5000,0x5,   0x2,0xc,0,0)
	PROT_READ | PROT_EXEC, MAP_PRIVATE
 685 mozilla-bin RET   mmap 1216962560/0x48896000
 685 mozilla-bin CALL  mmap(0x4889a000,0x1000,0x3,  0x12,0xc,0,0x3000)
	PROT_WRITE | PROT_READ, MAP_FIXED | MAP_PRIVATE
 685 mozilla-bin RET   mmap 1216978944/0x4889a000
 685 mozilla-bin CALL  mmap(0x4889b000,     0,0x3,0x1012,0xffffffff,0,0)
	PROT_WRITE | PROT_READ, MAP_ANON | MAP_FIXED | MAP_PRIVATE
 685 mozilla-bin RET   mmap 1216983040/0x4889b000

So nothing is actually shared (just cow).
why does in bother mapping in the zero length bss?

	David

-- 
David Laight: david@l8s.co.uk