Hello,

While I was browsing, I found that, in function Rm_session_client::detach(), there is a part that looping over Rm_client and unmap it:

for (Rm_client *rc = _clients.first(); rc; rc = rc->List<Rm_client>::Element::next()) { /* * XXX Unmapping managed dataspaces on kernels, which take a core- * local virtual address as unmap argument is not supported yet. * This is the case for Fiasco, Pistachio, and NOVA. On those * kernels, the unmap operation must be issued for each leaf * dataspace the managed dataspace is composed of. For kernels with * support for directed unmap (OKL4 or Codezero), unmap can be * simply applied for the contiguous virtual address region in the * client. */ if (!platform()->supports_direct_unmap() && dsc->is_managed() && dsc->core_local_addr() == 0) { PWRN("unmapping of managed dataspaces not yet supported"); break; } rc->unmap(dsc->core_local_addr() + region->offset(), // <=== this part region->base(), region->size()); }

The implementation of Rm_client::unmap is the following:

void Rm_client::unmap(addr_t core_local_base, addr_t virt_base, size_t size) { // TODO unmap it only from target space unmap_local(core_local_base, size >> get_page_size_log2()); }

In the above function, since it is not using any member variables of Rm_client, when Rm_session_client::detach() calls multiple of Rm_client::unmap it is just calling the same function of "unmap_local" with the same parameters. It results in calling l4_task_unmap multiple times with the same parameters. I'm just concern that this may not cause anything harmful.

Best, Jaeyong