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Commit 444f378b authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Revert "[PATCH] namespaces: fix exit race by splitting exit" 



This reverts commit 7a238fcb in
preparation for a better and simpler fix proposed by Eric Biederman
(and fixed up by Serge Hallyn)

Acked-by: default avatarSerge E. Hallyn <serue@us.ibm.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 8c8c4baf

include/linux/nsproxy.h

+11 −19
Original line number Diff line number Diff line
@@ -35,30 +35,22 @@ struct nsproxy *dup_namespaces(struct nsproxy *orig); 
int copy_namespaces(int flags, struct task_struct *tsk);

void get_task_namespaces(struct task_struct *tsk);

void free_nsproxy(struct nsproxy *ns);

struct nsproxy *put_nsproxy(struct nsproxy *ns);



static inline void finalize_put_nsproxy(struct nsproxy *ns)

static inline void put_nsproxy(struct nsproxy *ns)

{

	if (ns)

	if (atomic_dec_and_test(&ns->count)) {

		free_nsproxy(ns);

	}



static inline void put_and_finalize_nsproxy(struct nsproxy *ns)

{

	finalize_put_nsproxy(put_nsproxy(ns));

}



static inline struct nsproxy *preexit_task_namespaces(struct task_struct *p)

{

	return put_nsproxy(p->nsproxy);

}



static inline void exit_task_namespaces(struct task_struct *p,

						struct nsproxy *ns)

static inline void exit_task_namespaces(struct task_struct *p)

{

	struct nsproxy *ns = p->nsproxy;

	if (ns) {

		task_lock(p);

		p->nsproxy = NULL;

		task_unlock(p);

	finalize_put_nsproxy(ns);

		put_nsproxy(ns);

	}

}

#endif

kernel/exit.c

+2 −4
Original line number Diff line number Diff line
@@ -396,7 +396,7 @@ void daemonize(const char *name, ...) 
	current->fs = fs;

	atomic_inc(&fs->count);



	put_and_finalize_nsproxy(current->nsproxy);

	exit_task_namespaces(current);

	current->nsproxy = init_task.nsproxy;

	get_task_namespaces(current);
@@ -853,7 +853,6 @@ static void exit_notify(struct task_struct *tsk) 
fastcall NORET_TYPE void do_exit(long code)

{

	struct task_struct *tsk = current;

	struct nsproxy *ns;

	int group_dead;



	profile_task_exit(tsk);
@@ -939,9 +938,8 @@ fastcall NORET_TYPE void do_exit(long code) 


	tsk->exit_code = code;

	proc_exit_connector(tsk);

	ns = preexit_task_namespaces(tsk);

	exit_notify(tsk);

	exit_task_namespaces(tsk, ns);

	exit_task_namespaces(tsk);

#ifdef CONFIG_NUMA

	mpol_free(tsk->mempolicy);

	tsk->mempolicy = NULL;

kernel/fork.c

+2 −2
Original line number Diff line number Diff line
@@ -1265,7 +1265,7 @@ static struct task_struct *copy_process(unsigned long clone_flags, 
	return p;



bad_fork_cleanup_namespaces:

	put_and_finalize_nsproxy(p->nsproxy);

	exit_task_namespaces(p);

bad_fork_cleanup_keys:

	exit_keys(p);

bad_fork_cleanup_mm:
@@ -1711,7 +1711,7 @@ asmlinkage long sys_unshare(unsigned long unshare_flags) 
	}



	if (new_nsproxy)

		put_and_finalize_nsproxy(new_nsproxy);

		put_nsproxy(new_nsproxy);



bad_unshare_cleanup_ipc:

	if (new_ipc)

kernel/nsproxy.c

+1 −15
Original line number Diff line number Diff line
@@ -117,7 +117,7 @@ int copy_namespaces(int flags, struct task_struct *tsk) 
		goto out_pid;



out:

	put_and_finalize_nsproxy(old_ns);

	put_nsproxy(old_ns);

	return err;



out_pid:
@@ -135,20 +135,6 @@ int copy_namespaces(int flags, struct task_struct *tsk) 
	goto out;

}



struct nsproxy *put_nsproxy(struct nsproxy *ns)

{

	if (ns) {

		if (atomic_dec_and_test(&ns->count)) {

			if (ns->mnt_ns) {

				put_mnt_ns(ns->mnt_ns);

				ns->mnt_ns = NULL;

			}

			return ns;

		}

	}

	return NULL;

}



void free_nsproxy(struct nsproxy *ns)

{

	if (ns->mnt_ns)