From: Amir Shehata <ashehata@whamcloud.com>
Date: Tue, 30 Apr 2019 05:57:21 +0000 (-0700)
Subject: LU-12249 lnet: fix list corruption
X-Git-Tag: 2.12.55~25^2~35
X-Git-Url: https://git.whamcloud.com/?p=fs%2Flustre-release.git;a=commitdiff_plain;h=d799ac910cd6c980b40c81b76eaefb65b88904d0

LU-12249 lnet: fix list corruption

In shutdown the resend queues are cleared and freed. The monitor
thread state is set to shutdown. It is possible to get lnet_finalize()
called after the queues are freed. The code checks for ln_state to see
if we're shutting down. But in this case we should really be checking
ln_mt_state. The monitor thread is the one that matters in this case,
because it's the one which allocates and frees the resend queues.

Test-Parameters: forbuildonly
Signed-off-by: Amir Shehata <ashehata@whamcloud.com>
Change-Id: Ia077cec7a52ef5cd2e1b231437c6265ba9416b1b
Reviewed-on: https://review.whamcloud.com/34778
Reviewed-by: Olaf Weber <olaf.weber@hpe.com>
Reviewed-by: Sebastien Buisson <sbuisson@ddn.com>
Reviewed-by: Chris Horn <hornc@cray.com>
Tested-by: Jenkins
---

diff --git a/lnet/lnet/lib-move.c b/lnet/lnet/lib-move.c
index 8e8734b..df230bf 100644
--- a/lnet/lnet/lib-move.c
+++ b/lnet/lnet/lib-move.c
@@ -3389,7 +3389,9 @@ lnet_monitor_thread(void *arg)
 	lnet_prune_rc_data(1);
 
 	/* Shutting down */
+	lnet_net_lock(LNET_LOCK_EX);
 	the_lnet.ln_mt_state = LNET_MT_STATE_SHUTDOWN;
+	lnet_net_unlock(LNET_LOCK_EX);
 
 	/* signal that the monitor thread is exiting */
 	up(&the_lnet.ln_mt_signal);
@@ -3605,7 +3607,9 @@ int lnet_monitor_thr_start(void)
 
 	sema_init(&the_lnet.ln_mt_signal, 0);
 
+	lnet_net_lock(LNET_LOCK_EX);
 	the_lnet.ln_mt_state = LNET_MT_STATE_RUNNING;
+	lnet_net_unlock(LNET_LOCK_EX);
 	task = kthread_run(lnet_monitor_thread, NULL, "monitor_thread");
 	if (IS_ERR(task)) {
 		rc = PTR_ERR(task);
@@ -3619,13 +3623,17 @@ int lnet_monitor_thr_start(void)
 	return 0;
 
 clean_thread:
+	lnet_net_lock(LNET_LOCK_EX);
 	the_lnet.ln_mt_state = LNET_MT_STATE_STOPPING;
+	lnet_net_unlock(LNET_LOCK_EX);
 	/* block until event callback signals exit */
 	down(&the_lnet.ln_mt_signal);
 	/* clean up */
 	lnet_router_cleanup();
 free_mem:
+	lnet_net_lock(LNET_LOCK_EX);
 	the_lnet.ln_mt_state = LNET_MT_STATE_SHUTDOWN;
+	lnet_net_unlock(LNET_LOCK_EX);
 	lnet_rsp_tracker_clean();
 	lnet_clean_local_ni_recoveryq();
 	lnet_clean_peer_ni_recoveryq();
@@ -3646,7 +3654,9 @@ void lnet_monitor_thr_stop(void)
 		return;
 
 	LASSERT(the_lnet.ln_mt_state == LNET_MT_STATE_RUNNING);
+	lnet_net_lock(LNET_LOCK_EX);
 	the_lnet.ln_mt_state = LNET_MT_STATE_STOPPING;
+	lnet_net_unlock(LNET_LOCK_EX);
 
 	/* tell the monitor thread that we're shutting down */
 	wake_up(&the_lnet.ln_mt_waitq);
diff --git a/lnet/lnet/lib-msg.c b/lnet/lnet/lib-msg.c
index 74491a2..32aea2c 100644
--- a/lnet/lnet/lib-msg.c
+++ b/lnet/lnet/lib-msg.c
@@ -600,7 +600,7 @@ lnet_health_check(struct lnet_msg *msg)
 	bool lo = false;
 
 	/* if we're shutting down no point in handling health. */
-	if (the_lnet.ln_state != LNET_STATE_RUNNING)
+	if (the_lnet.ln_mt_state != LNET_MT_STATE_RUNNING)
 		return -1;
 
 	LASSERT(msg->msg_txni);
@@ -714,6 +714,12 @@ resend:
 
 	lnet_net_lock(msg->msg_tx_cpt);
 
+	/* check again under lock */
+	if (the_lnet.ln_mt_state != LNET_MT_STATE_RUNNING) {
+		lnet_net_unlock(msg->msg_tx_cpt);
+		return -1;
+	}
+
 	/*
 	 * remove message from the active list and reset it in preparation
 	 * for a resend. Two exception to this