From 6603859ca0be85441af86d350d68bc6144d5da9c Mon Sep 17 00:00:00 2001
From: Petr Mladek <pmladek@suse.com>
Date: May 10 2023 14:34:44 +0000
Subject: workqueue: Fix hung time report of worker pools (bsc#1211044).


---

diff --git a/patches.suse/workqueue-Fix-hung-time-report-of-worker-pools.patch b/patches.suse/workqueue-Fix-hung-time-report-of-worker-pools.patch
new file mode 100644
index 0000000..af14bb1
--- /dev/null
+++ b/patches.suse/workqueue-Fix-hung-time-report-of-worker-pools.patch
@@ -0,0 +1,60 @@
+From 335a42ebb0ca8ee9997a1731aaaae6dcd704c113 Mon Sep 17 00:00:00 2001
+From: Petr Mladek <pmladek@suse.com>
+Date: Tue, 7 Mar 2023 13:53:31 +0100
+Subject: [PATCH] workqueue: Fix hung time report of worker pools
+Git-commit: 335a42ebb0ca8ee9997a1731aaaae6dcd704c113
+Patch-mainline: v6.4-rc1
+References: bsc#1211044
+
+The workqueue watchdog prints a warning when there is no progress in
+a worker pool. Where the progress means that the pool started processing
+a pending work item.
+
+Note that it is perfectly fine to process work items much longer.
+The progress should be guaranteed by waking up or creating idle
+workers.
+
+show_one_worker_pool() prints state of non-idle worker pool. It shows
+a delay since the last pool->watchdog_ts.
+
+The timestamp is updated when a first pending work is queued in
+__queue_work(). Also it is updated when a work is dequeued for
+processing in worker_thread() and rescuer_thread().
+
+The delay is misleading when there is no pending work item. In this
+case it shows how long the last work item is being proceed. Show
+zero instead. There is no stall if there is no pending work.
+
+Fixes: 82607adcf9cdf40fb7b ("workqueue: implement lockup detector")
+Signed-off-by: Petr Mladek <pmladek@suse.com>
+Signed-off-by: Tejun Heo <tj@kernel.org>
+
+---
+ kernel/workqueue.c |   10 +++++++---
+ 1 file changed, 7 insertions(+), 3 deletions(-)
+
+--- a/kernel/workqueue.c
++++ b/kernel/workqueue.c
+@@ -4879,16 +4879,19 @@ void show_workqueue_state(void)
+ 	for_each_pool(pool, pi) {
+ 		struct worker *worker;
+ 		bool first = true;
++		unsigned long hung = 0;
+ 
+ 		spin_lock_irqsave(&pool->lock, flags);
+ 		if (pool->nr_workers == pool->nr_idle)
+ 			goto next_pool;
+ 
++		/* How long the first pending work is waiting for a worker. */
++		if (!list_empty(&pool->worklist))
++			hung = jiffies_to_msecs(jiffies - pool->watchdog_ts) / 1000;
++
+ 		pr_info("pool %d:", pool->id);
+ 		pr_cont_pool_info(pool);
+-		pr_cont(" hung=%us workers=%d",
+-			jiffies_to_msecs(jiffies - pool->watchdog_ts) / 1000,
+-			pool->nr_workers);
++		pr_cont(" hung=%lus workers=%d", hung, pool->nr_workers);
+ 		if (pool->manager)
+ 			pr_cont(" manager: %d",
+ 				task_pid_nr(pool->manager->task));
diff --git a/series.conf b/series.conf
index 6d6503d..1e30df2 100644
--- a/series.conf
+++ b/series.conf
@@ -63305,6 +63305,7 @@
 	patches.suse/USB-dwc3-fix-runtime-pm-imbalance-on-probe-errors.patch
 	patches.suse/USB-dwc3-fix-runtime-pm-imbalance-on-unbind.patch
 	patches.suse/usb-chipidea-fix-missing-goto-in-ci_hdrc_probe.patch
+	patches.suse/workqueue-Fix-hung-time-report-of-worker-pools.patch
 	patches.suse/xfs-verify-buffer-contents-when-we-skip-log-replay.patch
 
 	# dhowells/linux-fs keys-uefi