diff --git a/ipc/shm.c b/ipc/shm.c
index f239d87..faa46da 100644
--- a/ipc/shm.c
+++ b/ipc/shm.c
@@ -555,12 +555,14 @@
 	in_use = shm_ids(ns).in_use;
 
 	for (total = 0, next_id = 0; total < in_use; next_id++) {
+		struct kern_ipc_perm *ipc;
 		struct shmid_kernel *shp;
 		struct inode *inode;
 
-		shp = idr_find(&shm_ids(ns).ipcs_idr, next_id);
-		if (shp == NULL)
+		ipc = idr_find(&shm_ids(ns).ipcs_idr, next_id);
+		if (ipc == NULL)
 			continue;
+		shp = container_of(ipc, struct shmid_kernel, shm_perm);
 
 		inode = shp->shm_file->f_path.dentry->d_inode;