On Mon, Mar 13, 2017 at 10:37:24AM -0700, Andrei Vagin wrote: > > Here is one question inline. > > Acked-by: Andrei Vagin <avagin@xxxxxxxxxxxxx> Thanks! > > + > > + files = get_files_struct(task2); > > + if (!files) > > + return -EBADF; > > + > > + spin_lock(&files->file_lock); > > + filp_epoll = fcheck_files(files, slot.efd); > > + if (filp_epoll) > > + get_file(filp_epoll); > > + else > > + filp_tgt = ERR_PTR(-EBADF); > > + spin_unlock(&files->file_lock); > > + put_files_struct(files); > > Why can we not use fget here ^^^^ ? Because it's not @current's file table but foreigner process. So we make sure there is no expand_fdtable in progress and we test for file descriptor which is being freed.
