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LU-3032 ptlrpc: race in pinger (use-after-free situation)
[fs/lustre-release.git] / lustre / ptlrpc / pinger.c
index b42fb10..06dc234 100644 (file)
@@ -378,40 +378,36 @@ static int ptlrpc_pinger_main(void *arg)
         return 0;
 }
 
-static struct ptlrpc_thread *pinger_thread = NULL;
+static struct ptlrpc_thread pinger_thread;
 
 int ptlrpc_start_pinger(void)
 {
-        struct l_wait_info lwi = { 0 };
-        int rc;
+       struct l_wait_info lwi = { 0 };
+       int rc;
 #ifndef ENABLE_PINGER
-        return 0;
+       return 0;
 #endif
-        ENTRY;
+       ENTRY;
 
-        if (pinger_thread != NULL)
-                RETURN(-EALREADY);
+       if (!thread_is_init(&pinger_thread) &&
+           !thread_is_stopped(&pinger_thread))
+               RETURN(-EALREADY);
 
-        OBD_ALLOC_PTR(pinger_thread);
-        if (pinger_thread == NULL)
-                RETURN(-ENOMEM);
-        cfs_waitq_init(&pinger_thread->t_ctl_waitq);
-        cfs_waitq_init(&suspend_timeouts_waitq);
+       cfs_waitq_init(&pinger_thread.t_ctl_waitq);
+       cfs_waitq_init(&suspend_timeouts_waitq);
 
-       strcpy(pinger_thread->t_name, "ll_ping");
+       strcpy(pinger_thread.t_name, "ll_ping");
 
        /* CLONE_VM and CLONE_FILES just avoid a needless copy, because we
         * just drop the VM and FILES in cfs_daemonize_ctxt() right away. */
-        rc = cfs_create_thread(ptlrpc_pinger_main,
-                              pinger_thread, CFS_DAEMON_FLAGS);
-        if (rc < 0) {
-                CERROR("cannot start thread: %d\n", rc);
-                OBD_FREE(pinger_thread, sizeof(*pinger_thread));
-                pinger_thread = NULL;
-                RETURN(rc);
-        }
-        l_wait_event(pinger_thread->t_ctl_waitq,
-                     thread_is_running(pinger_thread), &lwi);
+       rc = cfs_create_thread(ptlrpc_pinger_main,
+                              &pinger_thread, CFS_DAEMON_FLAGS);
+       if (rc < 0) {
+               CERROR("cannot start thread: %d\n", rc);
+               RETURN(rc);
+       }
+       l_wait_event(pinger_thread.t_ctl_waitq,
+                    thread_is_running(&pinger_thread), &lwi);
 
        if (suppress_pings)
                CWARN("Pings will be suppressed at the request of the "
@@ -427,28 +423,24 @@ int ptlrpc_pinger_remove_timeouts(void);
 
 int ptlrpc_stop_pinger(void)
 {
-        struct l_wait_info lwi = { 0 };
-        int rc = 0;
+       struct l_wait_info lwi = { 0 };
 #ifndef ENABLE_PINGER
-        return 0;
+       return 0;
 #endif
-        ENTRY;
+       ENTRY;
 
-        if (pinger_thread == NULL)
-                RETURN(-EALREADY);
+       if (thread_is_init(&pinger_thread) ||
+           thread_is_stopped(&pinger_thread))
+               RETURN(-EALREADY);
 
-        ptlrpc_pinger_remove_timeouts();
-       mutex_lock(&pinger_mutex);
-        thread_set_flags(pinger_thread, SVC_STOPPING);
-        cfs_waitq_signal(&pinger_thread->t_ctl_waitq);
-       mutex_unlock(&pinger_mutex);
+       ptlrpc_pinger_remove_timeouts();
 
-        l_wait_event(pinger_thread->t_ctl_waitq,
-                     thread_is_stopped(pinger_thread), &lwi);
+       thread_set_flags(&pinger_thread, SVC_STOPPING);
+       cfs_waitq_signal(&pinger_thread.t_ctl_waitq);
 
-        OBD_FREE_PTR(pinger_thread);
-        pinger_thread = NULL;
-        RETURN(rc);
+       l_wait_event(pinger_thread.t_ctl_waitq,
+                    thread_is_stopped(&pinger_thread), &lwi);
+       RETURN(0);
 }
 
 void ptlrpc_pinger_sending_on_import(struct obd_import *imp)
@@ -633,8 +625,8 @@ int ptlrpc_pinger_remove_timeouts(void)
 void ptlrpc_pinger_wake_up()
 {
 #ifdef ENABLE_PINGER
-        thread_add_flags(pinger_thread, SVC_EVENT);
-        cfs_waitq_signal(&pinger_thread->t_ctl_waitq);
+       thread_add_flags(&pinger_thread, SVC_EVENT);
+       cfs_waitq_signal(&pinger_thread.t_ctl_waitq);
 #endif
 }