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From: Audra Mitchell <audra@redhat.com>
To: linux-kernel@vger.kernel.org
Cc: tj@kernel.org,
	jiangshanlai@gmail.com,
	hirokazu.yamauchi.hk@hitachi.com,
	ddouwsma@redhat.com,
	loberman@redhat.com,
	raquini@redhat.com
Subject: [PATCH v2] workqueue.c: Increase workqueue name length
Date: Wed, 10 Jan 2024 15:29:59 -0500
Message-ID: <20240110202959.249296-1-audra@redhat.com>
In-Reply-To: <20231215193954.1785069-1-audra@redhat.com>
References: <20231215193954.1785069-1-audra@redhat.com>
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Currently we limit the size of the workqueue name to 24 characters due to
commit ecf6881ff349 ("workqueue: make workqueue->name[] fixed len")
Increase the size to 32 characters and print a warning in the event
the requested name is larger than the limit of 32 characters.

Signed-off-by: Audra Mitchell <audra@redhat.com>
---
 kernel/workqueue.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 76e60faed892..cac3b8895c16 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -108,7 +108,7 @@ enum {
 	RESCUER_NICE_LEVEL	= MIN_NICE,
 	HIGHPRI_NICE_LEVEL	= MIN_NICE,
 
-	WQ_NAME_LEN		= 24,
+	WQ_NAME_LEN		= 32,
 };
 
 /*
@@ -4663,9 +4663,10 @@ struct workqueue_struct *alloc_workqueue(const char *fmt,
 					 unsigned int flags,
 					 int max_active, ...)
 {
-	va_list args;
+	va_list args, args_copy;
 	struct workqueue_struct *wq;
 	struct pool_workqueue *pwq;
+	int len;
 
 	/*
 	 * Unbound && max_active == 1 used to imply ordered, which is no longer
@@ -4692,6 +4693,13 @@ struct workqueue_struct *alloc_workqueue(const char *fmt,
 	}
 
 	va_start(args, max_active);
+	va_copy(args_copy, args);
+	len = vsnprintf(NULL, 0, fmt, args_copy);
+	WARN(len > WQ_NAME_LEN,
+		"workqueue: wq->name too long (%d). Truncated to WQ_NAME_LEN (%d)\n",
+		len, WQ_NAME_LEN);
+
+	va_end(args_copy);
 	vsnprintf(wq->name, sizeof(wq->name), fmt, args);
 	va_end(args);
 
-- 
2.43.0