On 09/16, Eric W. Biederman wrote: > > Oleg Nesterov <oleg@xxxxxxxxxx> writes: > > > As for binder.c, in this case we probably actually want to unshare ->files > > on exec so we can ignore it? > > Looking at the binder case it only captures ->files on mmap. Exec > ditches the mmap. So if the order of operations are correct than > the dropping of the old mm will also drop the count on files_struct > held by binder. > > So semantically binder should not effect locks on exec, Agreed, but it does. Before your "[PATCH 0/3] exec: Moving unshare_files_struct" unshare_files() is called before exec_mmap(). And even with this series we can have another CLONE_VM process. Howver, I think this doesn't really matter. binder does __fd_install(files), so if it actually has a reference to execing_task->files, I think it should be unshared anyway. > In short as long as we get the oder of operations correct we should be > able to safely ignore binder, and not have binder affect the results of > this code. Agreed. Oleg.
