linux-kernel - [PATCH] V2 init/main.c Enable watchdog

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Message-Id: <1540396387-20337-1-git-send-email-loberman@redhat.com>
Date:   Wed, 24 Oct 2018 11:53:07 -0400
From:   Laurence Oberman <loberman@...hat.com>
To:     linux-kernel@...r.kernel.org, loberman@...hat.com
Cc:     rdunlap@...radead.org
Subject: [PATCH] V2 init/main.c Enable watchdog_thresh control from kernel line 

Both graphics and serial consoles are exposed to hard lockups
when handling a large amount of messaging. The kernel watchdog_thresh
parameter up to now has not been available to be set on the kernel line for
early boot. 
This patch allows the setting of watchdog_thresh to be increased
when needed to avoid the hard lockups in the console code.

Signed-off-by: Laurence Oberman <loberman@...hat.com>
---
 init/main.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/init/main.c b/init/main.c
index e4a3160..5882750 100644
--- a/init/main.c
+++ b/init/main.c
@@ -977,6 +977,15 @@ static int __init set_debug_rodata(char *str)
 __setup("rodata=", set_debug_rodata);
 #endif
 
+static int __init
+is_watchdog_thresh_setup(char *str)
+{
+	get_option(&str, &watchdog_thresh);
+	return 1;
+}
+__setup("watchdog_thresh=", is_watchdog_thresh_setup);
+
+
 #ifdef CONFIG_STRICT_KERNEL_RWX
 static void mark_readonly(void)
 {
-- 
1.8.3.1

---
 Documentation/admin-guide/kernel-parameters.txt | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index bf03fe4..a5280a1 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -4615,6 +4615,14 @@
 			or other driver-specific files in the
 			Documentation/watchdog/ directory.
 
+	watchdog_thresh=
+			This parameter is now available as a kernel line
+			parameter. Use watchdog_thresh=30 as example
+			This will allow early boot changes of the current
+			default of 10s to be increased when needed to
+			avoid hard lockups.
+			Default: 10
+
 	workqueue.watchdog_thresh=
 			If CONFIG_WQ_WATCHDOG is configured, workqueue can
 			warn stall conditions and dump internal state to
-- 
1.8.3.1