Instead of holding the ipc lock for the entire function, use
the ipcctl_pre_down_nolock and only acquire the lock for
specific commands: RMID and SET.
Signed-off-by: Davidlohr Bueso <davidlohr.bu...@hp.com>
---
ipc/msg.c | 12 +++++++-----
1 file changed, 7 insertions(+), 5 deletions(-)
diff --git a/ipc/msg.c b/ipc/msg.c
index 4eaeb08..264ebe0 100644
--- a/ipc/msg.c
+++ b/ipc/msg.c
@@ -412,11 +412,10 @@ static int msgctl_down(struct ipc_namespace *ns, int
msqid, int cmd,
down_write(&msg_ids(ns).rw_mutex);
rcu_read_lock();
- ipcp = ipcctl_pre_down(ns, &msg_ids(ns), msqid, cmd,
- &msqid64.msg_perm, msqid64.msg_qbytes);
+ ipcp = ipcctl_pre_down_nolock(ns, &msg_ids(ns), msqid, cmd,
+ &msqid64.msg_perm, msqid64.msg_qbytes);
if (IS_ERR(ipcp)) {
err = PTR_ERR(ipcp);
- /* the ipc lock is not held upon failure */
goto out_unlock1;
}
@@ -424,10 +423,11 @@ static int msgctl_down(struct ipc_namespace *ns, int
msqid, int cmd,
err = security_msg_queue_msgctl(msq, cmd);
if (err)
- goto out_unlock0;
+ goto out_unlock1;
switch (cmd) {
case IPC_RMID:
+ ipc_lock_object(&msq->q_perm);
/* freeque unlocks the ipc object and rcu */
freeque(ns, ipcp);
goto out_up;
@@ -435,9 +435,10 @@ static int msgctl_down(struct ipc_namespace *ns, int
msqid, int cmd,
if (msqid64.msg_qbytes > ns->msg_ctlmnb &&
!capable(CAP_SYS_RESOURCE)) {
err = -EPERM;
- goto out_unlock0;
+ goto out_unlock1;
}
+ ipc_lock_object(&msq->q_perm);
err = ipc_update_perm(&msqid64.msg_perm, ipcp);
if (err)
goto out_unlock0;
@@ -456,6 +457,7 @@ static int msgctl_down(struct ipc_namespace *ns, int msqid,
int cmd,
break;
default:
err = -EINVAL;
+ goto out_unlock1;
}
out_unlock0:
--
1.7.11.7
--
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