linux-kernel - [PATCH v2 3/5] workqueue: Interrupted create

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Message-Id: <20230307125335.28805-4-pmladek@suse.com>
Date:   Tue,  7 Mar 2023 13:53:33 +0100
From:   Petr Mladek <pmladek@...e.com>
To:     Tejun Heo <tj@...nel.org>
Cc:     Lai Jiangshan <jiangshanlai@...il.com>,
        Michal Koutny <mkoutny@...e.com>, linux-kernel@...r.kernel.org,
        Petr Mladek <pmladek@...e.com>
Subject: [PATCH v2 3/5] workqueue: Interrupted create_worker() is not a repeated event

kthread_create_on_node() might get interrupted(). It is rare but realistic.
For example, when an unbound workqueue is allocated in module_init()
callback. It is done in the context of the "modprobe" process. And,
for example, systemd might kill pending processes when switching root
from initrd to the booted system.

The interrupt is a one-off event and the race might be hard to reproduce.
It is always worth printing.

Signed-off-by: Petr Mladek <pmladek@...e.com>
---
 kernel/workqueue.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 36ad9a4d65e4..16439d79d164 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -1961,8 +1961,13 @@ static struct worker *create_worker(struct worker_pool *pool)
 	worker->task = kthread_create_on_node(worker_thread, worker, pool->node,
 					      "kworker/%s", id_buf);
 	if (IS_ERR(worker->task)) {
-		pr_err_once("workqueue: Failed to create a worker thread: %pe",
-			    worker->task);
+		if (PTR_ERR(worker->task) == -EINTR) {
+			pr_err("workqueue: Interrupted when creating a worker thread \"kworker/%s\"\n",
+			       id_buf);
+		} else {
+			pr_err_once("workqueue: Failed to create a worker thread: %pe",
+				    worker->task);
+		}
 		goto fail;
 	}
 
-- 
2.35.3