diff --git a/LibOS/shim/include/shim_ipc.h b/LibOS/shim/include/shim_ipc.h
index f60c5a81..12ff9119 100644
--- a/LibOS/shim/include/shim_ipc.h
+++ b/LibOS/shim/include/shim_ipc.h
@@ -122,8 +122,8 @@ struct shim_ipc_resp {
 /* PID_CHECKPOINT: broadcast checkpointing */
 struct shim_ipc_checkpoint {
     IDTYPE cpsession;
-    char cpdir[1];
-} __attribute__((packed));
+    char cpdir[];
+};
 
 int ipc_checkpoint_send(const char* cpdir, IDTYPE cpsession);
 int ipc_checkpoint_callback(struct shim_ipc_msg* msg, struct shim_ipc_port* port);
@@ -204,7 +204,7 @@ struct pid_status {
 struct shim_ipc_pid_getstatus {
     int npids;
     IDTYPE pids[];
-} __attribute__((packed));
+};
 
 int ipc_pid_getstatus_send(struct shim_ipc_port* port, IDTYPE dest, int npids, IDTYPE* pids,
                            struct pid_status** status);
@@ -315,7 +315,7 @@ struct shim_ipc_sysv_movres {
     IDTYPE owner;
     LEASETYPE lease;
     char uri[1];
-} __attribute__((packed));
+};
 
 int ipc_sysv_movres_send(struct sysv_client* client, IDTYPE owner, const char* uri, LEASETYPE lease,
                          IDTYPE resid, enum sysv_type type);
@@ -349,7 +349,7 @@ struct shim_ipc_sysv_msgmov {
     LEASETYPE lease;
     unsigned short nscores;
     struct sysv_score scores[];
-} __attribute__((packed));
+};
 
 int ipc_sysv_msgmov_send(struct shim_ipc_port* port, IDTYPE dest, IDTYPE msgid, LEASETYPE lease,
                          struct sysv_score* scores, int nscores);
@@ -361,7 +361,7 @@ struct shim_ipc_sysv_semop {
     unsigned long timeout;
     int nsops;
     struct sembuf sops[];
-} __attribute__((packed));
+};
 
 #define IPC_SEM_NOTIMEOUT ((unsigned long)-1)
 
@@ -397,7 +397,7 @@ struct shim_ipc_sysv_semmov {
     LEASETYPE lease;
     unsigned short nsems, nsrcs, nscores;
     struct sem_backup sems[];
-} __attribute__((packed));
+};
 
 int ipc_sysv_semmov_send(struct shim_ipc_port* port, IDTYPE dest, IDTYPE semid, LEASETYPE lease,
                          struct sem_backup* sems, int nsems, struct sem_client_backup* srcs,
diff --git a/LibOS/shim/include/shim_ipc_ns.h b/LibOS/shim/include/shim_ipc_ns.h
index 035a79dd..ddf1745b 100644
--- a/LibOS/shim/include/shim_ipc_ns.h
+++ b/LibOS/shim/include/shim_ipc_ns.h
@@ -46,7 +46,7 @@ struct ipc_ns_offered {
     IDTYPE base, size;
     LEASETYPE lease;
     unsigned int owner_offset;
-} __attribute__((packed));
+};
 
 struct ipc_ns_client {
     IDTYPE vmid;
@@ -125,8 +125,7 @@ int NS_CALLBACK(lease)(IPC_CALLBACK_ARGS);
 NS_MSG_TYPE(offer) {
     IDTYPE base, size;
     LEASETYPE lease;
-}
-__attribute__((packed));
+};
 
 int NS_SEND(offer)(struct shim_ipc_port* port, IDTYPE dest, IDTYPE base, IDTYPE size,
                    LEASETYPE lease, unsigned long seq);
@@ -169,8 +168,7 @@ int NS_CALLBACK(queryall)(IPC_CALLBACK_ARGS);
 NS_MSG_TYPE(answer) {
     int nanswers;
     struct ipc_ns_offered answers[];
-}
-__attribute__((packed));
+};
 
 int NS_SEND(answer)(struct shim_ipc_port* port, IDTYPE dest, int nanswers,
                     struct ipc_ns_offered* answers, int nowners, struct ipc_ns_client** ownerdata,
@@ -185,8 +183,7 @@ int CONCAT2(NS, get_key)(NS_KEY* key, bool delete);
 /* FINDKEY */
 NS_MSG_TYPE(findkey) {
     NS_KEY key;
-}
-__attribute__((packed));
+};
 
 int NS_SEND(findkey)(NS_KEY* key);
 int NS_CALLBACK(findkey)(IPC_CALLBACK_ARGS);
@@ -195,8 +192,7 @@ int NS_CALLBACK(findkey)(IPC_CALLBACK_ARGS);
 NS_MSG_TYPE(tellkey) {
     NS_KEY key;
     IDTYPE id;
-}
-__attribute__((packed));
+};
 
 int NS_SEND(tellkey)(struct shim_ipc_port* port, IDTYPE dest, NS_KEY* key, IDTYPE id,
                      unsigned long seq);
diff --git a/LibOS/shim/include/shim_sysv.h b/LibOS/shim/include/shim_sysv.h
index 6dae3a96..c82e6adf 100644
--- a/LibOS/shim/include/shim_sysv.h
+++ b/LibOS/shim/include/shim_sysv.h
@@ -100,7 +100,7 @@ struct msg_req {
     unsigned short size;
     int flags;
     struct sysv_client dest;
-} __attribute__((packed));
+};
 
 #define INIT_MSG_TYPE_SIZE 32
 
diff --git a/LibOS/shim/src/ipc/shim_ipc.c b/LibOS/shim/src/ipc/shim_ipc.c
index dd293e29..ad81a908 100644
--- a/LibOS/shim/src/ipc/shim_ipc.c
+++ b/LibOS/shim/src/ipc/shim_ipc.c
@@ -449,7 +449,7 @@ int ipc_checkpoint_send(const char* cpdir, IDTYPE cpsession) {
     int ret;
     size_t len = strlen(cpdir);
 
-    size_t total_msg_size    = get_ipc_msg_size(sizeof(struct shim_ipc_checkpoint) + len);
+    size_t total_msg_size    = get_ipc_msg_size(sizeof(struct shim_ipc_checkpoint) + len + 1);
     struct shim_ipc_msg* msg = __alloca(total_msg_size);
     init_ipc_msg(msg, IPC_CHECKPOINT, total_msg_size, 0);
 
diff --git a/LibOS/shim/src/sys/shim_poll.c b/LibOS/shim/src/sys/shim_poll.c
index 03cdaf6c..48f25c29 100644
--- a/LibOS/shim/src/sys/shim_poll.c
+++ b/LibOS/shim/src/sys/shim_poll.c
@@ -99,7 +99,7 @@ struct poll_handle {
     struct shim_handle * handle;
     struct poll_handle * next;
     struct poll_handle * children;
-} __attribute__((packed));
+};
 
 #define POLL_NOTIMEOUT  ((uint64_t)-1)