From c0b2fc316599d6cd875b6b8cafa67f03b9512b4d Mon Sep 17 00:00:00 2001 From: Serge Hallyn Date: Mon, 2 Oct 2006 02:18:18 -0700 Subject: [PATCH] [PATCH] uts: copy nsproxy only when needed The nsproxy was being copied in unshare() when anything was being unshared, even if it was something not referenced from nsproxy. This should end up in some cases with far more memory usage than necessary. Signed-off-by: Serge Hallyn Cc: Kirill Korotaev Cc: "Eric W. Biederman" Cc: Herbert Poetzl Cc: Andrey Savochkin Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/fork.c | 20 ++++++++++++++------ 1 file changed, 14 insertions(+), 6 deletions(-) diff --git a/kernel/fork.c b/kernel/fork.c index c08cf05dd5..208dd99f13 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -1606,7 +1606,7 @@ asmlinkage long sys_unshare(unsigned long unshare_flags) struct mm_struct *mm, *new_mm = NULL, *active_mm = NULL; struct files_struct *fd, *new_fd = NULL; struct sem_undo_list *new_ulist = NULL; - struct nsproxy *new_nsproxy, *old_nsproxy; + struct nsproxy *new_nsproxy = NULL, *old_nsproxy = NULL; struct uts_namespace *uts, *new_uts = NULL; check_unshare_flags(&unshare_flags); @@ -1634,18 +1634,24 @@ asmlinkage long sys_unshare(unsigned long unshare_flags) if ((err = unshare_utsname(unshare_flags, &new_uts))) goto bad_unshare_cleanup_semundo; - if (new_fs || new_ns || new_sigh || new_mm || new_fd || new_ulist || - new_uts) { - + if (new_ns || new_uts) { old_nsproxy = current->nsproxy; new_nsproxy = dup_namespaces(old_nsproxy); if (!new_nsproxy) { err = -ENOMEM; goto bad_unshare_cleanup_uts; } + } + + if (new_fs || new_ns || new_sigh || new_mm || new_fd || new_ulist || + new_uts) { task_lock(current); - current->nsproxy = new_nsproxy; + + if (new_nsproxy) { + current->nsproxy = new_nsproxy; + new_nsproxy = old_nsproxy; + } if (new_fs) { fs = current->fs; @@ -1687,9 +1693,11 @@ asmlinkage long sys_unshare(unsigned long unshare_flags) } task_unlock(current); - put_nsproxy(old_nsproxy); } + if (new_nsproxy) + put_nsproxy(new_nsproxy); + bad_unshare_cleanup_uts: if (new_uts) put_uts_ns(new_uts); -- 2.39.5