Commit c0b2fc31 authored by Serge Hallyn's avatar Serge Hallyn Committed by Linus Torvalds
Browse files

[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: default avatarSerge Hallyn <serue@us.ibm.com>
Cc: Kirill Korotaev <dev@openvz.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Herbert Poetzl <herbert@13thfloor.at>
Cc: Andrey Savochkin <saw@sw.ru>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 071df104

kernel/fork.c

+14 −6
Original line number Diff line number Diff line
@@ -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);



		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);

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