[PATCH] V4 init/main.c Enable watchdog_thresh control from kernel line

[PATCH] V4 init/main.c Enable watchdog_thresh control from kernel line

[Laurence Oberman]

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@redhat.com>
---
 Documentation/admin-guide/kernel-parameters.txt | 7 +++++++
 init/main.c                                     | 8 ++++++++
 2 files changed, 15 insertions(+)

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 4cdcd1a..05f76b8 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -4932,6 +4932,13 @@
 			or other driver-specific files in the
 			Documentation/watchdog/ directory.
 
+	watchdog_thresh=
+			This parameter allows early boot to change the
+			value of the watchdog timeout threshold from the default
+			of 10 seconds to avoid hard lockups.  Example:
+			 watchdog_thresh=30
+			Default: 10
+
 	workqueue.watchdog_thresh=
 			If CONFIG_WQ_WATCHDOG is configured, workqueue can
 			warn stall conditions and dump internal state to
diff --git a/init/main.c b/init/main.c
index 1c3f902..ae45291 100644
--- a/init/main.c
+++ b/init/main.c
@@ -1038,6 +1038,14 @@ 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

Re: [PATCH] V4 init/main.c Enable watchdog_thresh control from kernel line

[Randy Dunlap]

On 10/24/18 11:06 AM, Laurence Oberman wrote:
> 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@redhat.com>

Acked-by: Randy Dunlap <rdunlap@infradead.org>

Thanks.

> ---
>  Documentation/admin-guide/kernel-parameters.txt | 7 +++++++
>  init/main.c                                     | 8 ++++++++
>  2 files changed, 15 insertions(+)
> 
> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> index 4cdcd1a..05f76b8 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt
> @@ -4932,6 +4932,13 @@
>  			or other driver-specific files in the
>  			Documentation/watchdog/ directory.
>  
> +	watchdog_thresh=
> +			This parameter allows early boot to change the
> +			value of the watchdog timeout threshold from the default
> +			of 10 seconds to avoid hard lockups.  Example:
> +			 watchdog_thresh=30
> +			Default: 10
> +
>  	workqueue.watchdog_thresh=
>  			If CONFIG_WQ_WATCHDOG is configured, workqueue can
>  			warn stall conditions and dump internal state to
> diff --git a/init/main.c b/init/main.c
> index 1c3f902..ae45291 100644
> --- a/init/main.c
> +++ b/init/main.c
> @@ -1038,6 +1038,14 @@ 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)
>  {
> 


-- 
~Randy

Re: [PATCH] V4 init/main.c Enable watchdog_thresh control from kernel line

[Randy Dunlap]

On 10/24/18 11:06 AM, Laurence Oberman wrote:
> 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@redhat.com>
> ---
>  Documentation/admin-guide/kernel-parameters.txt | 7 +++++++
>  init/main.c                                     | 8 ++++++++
>  2 files changed, 15 insertions(+)
> 

Laurence,
Here are a few more changes for you to consider.


> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> index 4cdcd1a..05f76b8 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt
> @@ -4932,6 +4932,13 @@
>  			or other driver-specific files in the
>  			Documentation/watchdog/ directory.
>  
> +	watchdog_thresh=
> +			This parameter allows early boot to change the
> +			value of the watchdog timeout threshold from the default
> +			of 10 seconds to avoid hard lockups.  Example:
> +			 watchdog_thresh=30

No extra char indent above.

> +			Default: 10
> +
>  	workqueue.watchdog_thresh=
>  			If CONFIG_WQ_WATCHDOG is configured, workqueue can
>  			warn stall conditions and dump internal state to
> diff --git a/init/main.c b/init/main.c
> index 1c3f902..ae45291 100644
> --- a/init/main.c
> +++ b/init/main.c
> @@ -1038,6 +1038,14 @@ static int __init set_debug_rodata(char *str)
>  __setup("rodata=", set_debug_rodata);
>  #endif
>  

#ifdef CONFIG_LOCKUP_DETECTOR

extern int watchdog_thresh;

> +static int __init is_watchdog_thresh_setup(char *str)
> +{
> +	get_option(&str, &watchdog_thresh);
> +	return 1;
> +}
> +__setup("watchdog_thresh=", is_watchdog_thresh_setup);
> +
#endif

and I would change the function name above to just watchdog_thresh_setup()
or setup_watchdog_thresh().


> +
>  #ifdef CONFIG_STRICT_KERNEL_RWX
>  static void mark_readonly(void)
>  {
> 


-- 
~Randy

Re: [PATCH] V4 init/main.c Enable watchdog_thresh control from kernel line

[kbuild test robot]

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Hi Laurence,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on linux-sof-driver/master]
[also build test ERROR on v4.19 next-20181029]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Laurence-Oberman/V4-init-main-c-Enable-watchdog_thresh-control-from-kernel-line/20181025-040136
base:   https://github.com/thesofproject/linux master
config: i386-randconfig-k3-10291547 (attached as .config)
compiler: gcc-7 (Debian 7.3.0-1) 7.3.0
reproduce:
        # save the attached .config to linux build tree
        make ARCH=i386 

All errors (new ones prefixed by >>):

   init/main.c: In function 'is_watchdog_thresh_setup':
>> init/main.c:1036:20: error: 'watchdog_thresh' undeclared (first use in this function); did you mean 'proc_watchdog_thresh'?
     get_option(&str, &watchdog_thresh);
                       ^~~~~~~~~~~~~~~
                       proc_watchdog_thresh
   init/main.c:1036:20: note: each undeclared identifier is reported only once for each function it appears in

vim +1036 init/main.c

  1033	
  1034	static int __init is_watchdog_thresh_setup(char *str)
  1035	{
> 1036		get_option(&str, &watchdog_thresh);
  1037		return 1;
  1038	}
  1039	__setup("watchdog_thresh=", is_watchdog_thresh_setup);
  1040	
  1041	

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

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