diff --git a/include/linux/sched.h b/include/linux/sched.h
index b21e9218..db2f647 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -33,6 +33,7 @@
 
 #include <linux/smp.h>
 #include <linux/sem.h>
+#include <linux/shm.h>
 #include <linux/signal.h>
 #include <linux/compiler.h>
 #include <linux/completion.h>
@@ -1385,6 +1386,7 @@
 #ifdef CONFIG_SYSVIPC
 /* ipc stuff */
 	struct sysv_sem sysvsem;
+	struct sysv_shm sysvshm;
 #endif
 #ifdef CONFIG_DETECT_HUNG_TASK
 /* hung task detection */
diff --git a/include/linux/shm.h b/include/linux/shm.h
index 57d7770..fd20638 100644
--- a/include/linux/shm.h
+++ b/include/linux/shm.h
@@ -1,6 +1,7 @@
 #ifndef _LINUX_SHM_H_
 #define _LINUX_SHM_H_
 
+#include <linux/list.h>
 #include <asm/page.h>
 #include <uapi/linux/shm.h>
 #include <asm/shmparam.h>
@@ -20,6 +21,7 @@
 
 	/* The task created the shm object.  NULL if the task is dead. */
 	struct task_struct	*shm_creator;
+	struct list_head	shm_clist;	/* list by creator */
 };
 
 /* shm_mode upper byte flags */
@@ -44,11 +46,20 @@
 #define SHM_HUGE_1GB    (30 << SHM_HUGE_SHIFT)
 
 #ifdef CONFIG_SYSVIPC
+struct sysv_shm {
+	struct list_head shm_clist;
+};
+
 long do_shmat(int shmid, char __user *shmaddr, int shmflg, unsigned long *addr,
 	      unsigned long shmlba);
 extern int is_file_shm_hugepages(struct file *file);
-extern void exit_shm(struct task_struct *task);
+void exit_shm(struct task_struct *task);
+#define shm_init_task(task) INIT_LIST_HEAD(&(task)->sysvshm.shm_clist)
 #else
+struct sysv_shm {
+	/* empty */
+};
+
 static inline long do_shmat(int shmid, char __user *shmaddr,
 			    int shmflg, unsigned long *addr,
 			    unsigned long shmlba)
@@ -62,6 +73,9 @@
 static inline void exit_shm(struct task_struct *task)
 {
 }
+static inline void shm_init_task(struct task_struct *task)
+{
+}
 #endif
 
 #endif /* _LINUX_SHM_H_ */
diff --git a/ipc/shm.c b/ipc/shm.c
index 89fc354..1fc3a61 100644
--- a/ipc/shm.c
+++ b/ipc/shm.c
@@ -178,6 +178,7 @@
 
 static inline void shm_rmid(struct ipc_namespace *ns, struct shmid_kernel *s)
 {
+	list_del(&s->shm_clist);
 	ipc_rmid(&shm_ids(ns), &s->shm_perm);
 }
 
@@ -268,14 +269,10 @@
 }
 
 /* Called with ns->shm_ids(ns).rwsem locked */
-static int shm_try_destroy_current(int id, void *p, void *data)
+static void shm_mark_orphan(struct shmid_kernel *shp, struct ipc_namespace *ns)
 {
-	struct ipc_namespace *ns = data;
-	struct kern_ipc_perm *ipcp = p;
-	struct shmid_kernel *shp = container_of(ipcp, struct shmid_kernel, shm_perm);
-
-	if (shp->shm_creator != current)
-		return 0;
+	if (WARN_ON(shp->shm_creator != current)) /* Remove me when it works */
+		return;
 
 	/*
 	 * Mark it as orphaned to destroy the segment when
@@ -289,13 +286,12 @@
 	 * is not set, it shouldn't be deleted here.
 	 */
 	if (!ns->shm_rmid_forced)
-		return 0;
+		return;
 
 	if (shm_may_destroy(ns, shp)) {
 		shm_lock_by_ptr(shp);
 		shm_destroy(ns, shp);
 	}
-	return 0;
 }
 
 /* Called with ns->shm_ids(ns).rwsem locked */
@@ -333,14 +329,17 @@
 void exit_shm(struct task_struct *task)
 {
 	struct ipc_namespace *ns = task->nsproxy->ipc_ns;
+	struct shmid_kernel *shp, *n;
 
 	if (shm_ids(ns).in_use == 0)
 		return;
 
 	/* Destroy all already created segments, but not mapped yet */
 	down_write(&shm_ids(ns).rwsem);
-	if (shm_ids(ns).in_use)
-		idr_for_each(&shm_ids(ns).ipcs_idr, &shm_try_destroy_current, ns);
+	list_for_each_entry_safe(shp, n, &task->sysvshm.shm_clist, shm_clist)
+		shm_mark_orphan(shp, ns);
+	/* remove the list head from any segments still attached */
+	list_del(&task->sysvshm.shm_clist);
 	up_write(&shm_ids(ns).rwsem);
 }
 
@@ -561,6 +560,7 @@
 	shp->shm_nattch = 0;
 	shp->shm_file = file;
 	shp->shm_creator = current;
+	list_add(&shp->shm_clist, &current->sysvshm.shm_clist);
 
 	/*
 	 * shmid gets reported as "inode#" in /proc/pid/maps.
diff --git a/kernel/fork.c b/kernel/fork.c
index 86da59e..fa91243 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1362,6 +1362,7 @@
 	if (retval)
 		goto bad_fork_cleanup_policy;
 	/* copy all the process information */
+	shm_init_task(p);
 	retval = copy_semundo(clone_flags, p);
 	if (retval)
 		goto bad_fork_cleanup_audit;
@@ -1913,6 +1914,11 @@
 			 */
 			exit_sem(current);
 		}
+		if (unshare_flags & CLONE_NEWIPC) {
+			/* Orphan segments in old ns (see sem above). */
+			exit_shm(current);
+			shm_init_task(current);
+		}
 
 		if (new_nsproxy)
 			switch_task_namespaces(current, new_nsproxy);