[PATCH] hangcheck-timer: use pr_crit and fix coding style

[PATCH] hangcheck-timer: use pr_crit and fix coding style

[Clint George]

Fix coding style issues and improve logging in hangcheck-timer such as replace printk(KERN_CRIT ...) to pr_crit(...) where applicable and replace non-standard %Ld with %lld in debug prints and use proper pr_debug/pr_crit for kernel logging.

No functional changes were made to hangcheck logic.

Testing:
- Verified timer firing and margin detection using "hangtest" module that i created (I will paste the code below for reference) and checked dmesg logs for expected output: "Hangcheck: hangcheck value past margin!".
- Used Static Analysis tools
- Ensured module builds and inserts cleanly after changes.

Let me know if you want me to do more testing on this module.

[] hangtest.c (testing module i created to test hangcheck-timer module):

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Clint George");
MODULE_DESCRIPTION("Hang test for testing hangcheck-timer");

static int hang_duration = 20;
module_param(hang_duration, int, 0644);

static int __init hangtest_init(void) {
    unsigned long timeout;

    printk(KERN_INFO "hangtest: Disabling interrupts for %d seconds...\n", hang_duration);

    local_irq_disable();
    preempt_disable();

    timeout = jiffies + (hang_duration * HZ);
    while (time_before(jiffies, timeout)) {
        cpu_relax();
        barrier();
    }

    preempt_enable();
    local_irq_enable();

    printk(KERN_INFO "hangtest: Interrupts re-enabled\n");
//    return 0;
    return -EINVAL; // Return error so module doesn't stay loaded
}

static void __exit hangtest_exit(void) {
    printk(KERN_INFO "hangtest: Exit\n");
}

module_init(hangtest_init);
module_exit(hangtest_exit);

Signed-off-by: Clint George <clintbgeorge@gmail.com>
---
 drivers/char/hangcheck-timer.c | 25 +++++++++++++++----------
 1 file changed, 15 insertions(+), 10 deletions(-)

diff --git a/drivers/char/hangcheck-timer.c b/drivers/char/hangcheck-timer.c
index 497fc167c..a95e6d608 100644
--- a/drivers/char/hangcheck-timer.c
+++ b/drivers/char/hangcheck-timer.c
@@ -69,7 +69,8 @@ MODULE_VERSION(VERSION_STR);
 static int __init hangcheck_parse_tick(char *str)
 {
 	int par;
-	if (get_option(&str,&par))
+
+	if (get_option(&str, &par))
 		hangcheck_tick = par;
 	return 1;
 }
@@ -77,7 +78,8 @@ static int __init hangcheck_parse_tick(char *str)
 static int __init hangcheck_parse_margin(char *str)
 {
 	int par;
-	if (get_option(&str,&par))
+
+	if (get_option(&str, &par))
 		hangcheck_margin = par;
 	return 1;
 }
@@ -85,7 +87,8 @@ static int __init hangcheck_parse_margin(char *str)
 static int __init hangcheck_parse_reboot(char *str)
 {
 	int par;
-	if (get_option(&str,&par))
+
+	if (get_option(&str, &par))
 		hangcheck_reboot = par;
 	return 1;
 }
@@ -93,7 +96,8 @@ static int __init hangcheck_parse_reboot(char *str)
 static int __init hangcheck_parse_dump_tasks(char *str)
 {
 	int par;
-	if (get_option(&str,&par))
+
+	if (get_option(&str, &par))
 		hangcheck_dump_tasks = par;
 	return 1;
 }
@@ -126,23 +130,24 @@ static void hangcheck_fire(struct timer_list *unused)
 
 	if (tsc_diff > hangcheck_tsc_margin) {
 		if (hangcheck_dump_tasks) {
-			printk(KERN_CRIT "Hangcheck: Task state:\n");
+			pr_crit("Hangcheck: Task state:\n");
+
 #ifdef CONFIG_MAGIC_SYSRQ
 			handle_sysrq('t');
 #endif  /* CONFIG_MAGIC_SYSRQ */
 		}
 		if (hangcheck_reboot) {
-			printk(KERN_CRIT "Hangcheck: hangcheck is restarting the machine.\n");
+			pr_crit("Hangcheck: hangcheck is restarting the machine.\n");
 			emergency_restart();
 		} else {
-			printk(KERN_CRIT "Hangcheck: hangcheck value past margin!\n");
+			pr_crit("Hangcheck: hangcheck value past margin!\n");
 		}
 	}
 #if 0
 	/*
 	 * Enable to investigate delays in detail
 	 */
-	printk("Hangcheck: called %Ld ns since last time (%Ld ns overshoot)\n",
+	pr_debug("Hangcheck: called %lld ns since last time (%lld ns overshoot)\n",
 			tsc_diff, tsc_diff - hangcheck_tick*TIMER_FREQ);
 #endif
 	mod_timer(&hangcheck_ticktock, jiffies + (hangcheck_tick*HZ));
@@ -152,7 +157,7 @@ static void hangcheck_fire(struct timer_list *unused)
 
 static int __init hangcheck_init(void)
 {
-	printk("Hangcheck: starting hangcheck timer %s (tick is %d seconds, margin is %d seconds).\n",
+	pr_debug("Hangcheck: starting hangcheck timer %s (tick is %d seconds, margin is %d seconds).\n",
 	       VERSION_STR, hangcheck_tick, hangcheck_margin);
 	hangcheck_tsc_margin =
 		(unsigned long long)hangcheck_margin + hangcheck_tick;
@@ -168,7 +173,7 @@ static int __init hangcheck_init(void)
 static void __exit hangcheck_exit(void)
 {
 	timer_delete_sync(&hangcheck_ticktock);
-        printk("Hangcheck: Stopped hangcheck timer.\n");
+	pr_debug("Hangcheck: Stopped hangcheck timer.\n");
 }
 
 module_init(hangcheck_init);
-- 
2.34.1

Re: [PATCH] hangcheck-timer: use pr_crit and fix coding style

[David Hunter]

On 10/18/25 12:00, Clint George wrote:
> Testing:
> - Verified timer firing and margin detection using "hangtest" module that i created (I will paste the code below for reference) and checked dmesg logs for expected output: "Hangcheck: hangcheck value past margin!".
> - Used Static Analysis tools
> - Ensured module builds and inserts cleanly after changes.
> 
> Let me know if you want me to do more testing on this module.
> 
> [] hangtest.c (testing module i created to test hangcheck-timer module):
> 
> MODULE_LICENSE("GPL");
> MODULE_AUTHOR("Clint George");
> MODULE_DESCRIPTION("Hang test for testing hangcheck-timer");
> 
> static int hang_duration = 20;
> module_param(hang_duration, int, 0644);
> 
> static int __init hangtest_init(void) {
>     unsigned long timeout;
> 
>     printk(KERN_INFO "hangtest: Disabling interrupts for %d seconds...\n", hang_duration);
> 
>     local_irq_disable();
>     preempt_disable();
> 
>     timeout = jiffies + (hang_duration * HZ);
>     while (time_before(jiffies, timeout)) {
>         cpu_relax();
>         barrier();
>     }
> 
>     preempt_enable();
>     local_irq_enable();
> 
>     printk(KERN_INFO "hangtest: Interrupts re-enabled\n");
> //    return 0;
>     return -EINVAL; // Return error so module doesn't stay loaded
> }
> 
> static void __exit hangtest_exit(void) {
>     printk(KERN_INFO "hangtest: Exit\n");
> }
> 
> module_init(hangtest_init);
> module_exit(hangtest_exit);


Well done for describing the testing you did, but try to put it in the
change log. As of now, it is in the commit message, which means that if
your patch is committed, people using git log, would be able to see all
of this, but this is something that is only needed for the maintainers,
not for future code viewers.

Plus, they can always recreate your patch if they need to.

Thanks,
David Hunter

[PATCH] hangcheck-timer: use pr_crit and fix coding style

[Clint George]

Fix coding style issues and improve logging in hangcheck-timer such as replace printk(KERN_CRIT ...) to pr_crit(...) where applicable and replace non-standard %Ld with %lld in debug prints and use proper pr_debug/pr_crit for kernel logging.

No functional changes were made to hangcheck logic.

Signed-off-by: Clint George <clintbgeorge@gmail.com>
---

Testing:
- Verified timer firing and margin detection using "hangtest" module that i created (I will paste the code below for reference) and checked dmesg logs for expected output: "Hangcheck: hangcheck value past margin!".
- Used Static Analysis tools
- Ensured module builds and inserts cleanly after changes.

Let me know if you want me to do more testing on this module.

[] hangtest.c (testing module i created to test hangcheck-timer module):

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Clint George");
MODULE_DESCRIPTION("Hang test for testing hangcheck-timer");

static int hang_duration = 20;
module_param(hang_duration, int, 0644);

static int __init hangtest_init(void) {
    unsigned long timeout;

    printk(KERN_INFO "hangtest: Disabling interrupts for %d seconds...\n", hang_duration);

    local_irq_disable();
    preempt_disable();

    timeout = jiffies + (hang_duration * HZ);
    while (time_before(jiffies, timeout)) {
        cpu_relax();
        barrier();
    }

    preempt_enable();
    local_irq_enable();

    printk(KERN_INFO "hangtest: Interrupts re-enabled\n");
//    return 0;
    return -EINVAL; // Return error so module doesn't stay loaded
}

static void __exit hangtest_exit(void) {
    printk(KERN_INFO "hangtest: Exit\n");
}

module_init(hangtest_init);
module_exit(hangtest_exit);

 drivers/char/hangcheck-timer.c | 25 +++++++++++++++----------
 1 file changed, 15 insertions(+), 10 deletions(-)

diff --git a/drivers/char/hangcheck-timer.c b/drivers/char/hangcheck-timer.c
index 497fc167c..a95e6d608 100644
--- a/drivers/char/hangcheck-timer.c
+++ b/drivers/char/hangcheck-timer.c
@@ -69,7 +69,8 @@ MODULE_VERSION(VERSION_STR);
 static int __init hangcheck_parse_tick(char *str)
 {
 	int par;
-	if (get_option(&str,&par))
+
+	if (get_option(&str, &par))
 		hangcheck_tick = par;
 	return 1;
 }
@@ -77,7 +78,8 @@ static int __init hangcheck_parse_tick(char *str)
 static int __init hangcheck_parse_margin(char *str)
 {
 	int par;
-	if (get_option(&str,&par))
+
+	if (get_option(&str, &par))
 		hangcheck_margin = par;
 	return 1;
 }
@@ -85,7 +87,8 @@ static int __init hangcheck_parse_margin(char *str)
 static int __init hangcheck_parse_reboot(char *str)
 {
 	int par;
-	if (get_option(&str,&par))
+
+	if (get_option(&str, &par))
 		hangcheck_reboot = par;
 	return 1;
 }
@@ -93,7 +96,8 @@ static int __init hangcheck_parse_reboot(char *str)
 static int __init hangcheck_parse_dump_tasks(char *str)
 {
 	int par;
-	if (get_option(&str,&par))
+
+	if (get_option(&str, &par))
 		hangcheck_dump_tasks = par;
 	return 1;
 }
@@ -126,23 +130,24 @@ static void hangcheck_fire(struct timer_list *unused)
 
 	if (tsc_diff > hangcheck_tsc_margin) {
 		if (hangcheck_dump_tasks) {
-			printk(KERN_CRIT "Hangcheck: Task state:\n");
+			pr_crit("Hangcheck: Task state:\n");
+
 #ifdef CONFIG_MAGIC_SYSRQ
 			handle_sysrq('t');
 #endif  /* CONFIG_MAGIC_SYSRQ */
 		}
 		if (hangcheck_reboot) {
-			printk(KERN_CRIT "Hangcheck: hangcheck is restarting the machine.\n");
+			pr_crit("Hangcheck: hangcheck is restarting the machine.\n");
 			emergency_restart();
 		} else {
-			printk(KERN_CRIT "Hangcheck: hangcheck value past margin!\n");
+			pr_crit("Hangcheck: hangcheck value past margin!\n");
 		}
 	}
 #if 0
 	/*
 	 * Enable to investigate delays in detail
 	 */
-	printk("Hangcheck: called %Ld ns since last time (%Ld ns overshoot)\n",
+	pr_debug("Hangcheck: called %lld ns since last time (%lld ns overshoot)\n",
 			tsc_diff, tsc_diff - hangcheck_tick*TIMER_FREQ);
 #endif
 	mod_timer(&hangcheck_ticktock, jiffies + (hangcheck_tick*HZ));
@@ -152,7 +157,7 @@ static void hangcheck_fire(struct timer_list *unused)
 
 static int __init hangcheck_init(void)
 {
-	printk("Hangcheck: starting hangcheck timer %s (tick is %d seconds, margin is %d seconds).\n",
+	pr_debug("Hangcheck: starting hangcheck timer %s (tick is %d seconds, margin is %d seconds).\n",
 	       VERSION_STR, hangcheck_tick, hangcheck_margin);
 	hangcheck_tsc_margin =
 		(unsigned long long)hangcheck_margin + hangcheck_tick;
@@ -168,7 +173,7 @@ static int __init hangcheck_init(void)
 static void __exit hangcheck_exit(void)
 {
 	timer_delete_sync(&hangcheck_ticktock);
-        printk("Hangcheck: Stopped hangcheck timer.\n");
+	pr_debug("Hangcheck: Stopped hangcheck timer.\n");
 }
 
 module_init(hangcheck_init);
-- 
2.34.1

Re: [PATCH] hangcheck-timer: use pr_crit and fix coding style

[Greg KH]

On Wed, Nov 05, 2025 at 07:35:41PM +0530, Clint George wrote:
> Fix coding style issues and improve logging in hangcheck-timer such as replace printk(KERN_CRIT ...) to pr_crit(...) where applicable and replace non-standard %Ld with %lld in debug prints and use proper pr_debug/pr_crit for kernel logging.

Please wrap changelog comments at 72 columns.

Also, please split this up into "one patch per logical thing", as you
shouldn't be mixing them into one change.


thanks,

greg k-h

[PATCH v2 0/3] hangcheck-timer: coding style improvements

[Clint George]

This series improves coding style in hangcheck-timer:

Clint George (3):
  hangcheck-timer: replace printk(KERN_CRIT) with pr_crit
  hangcheck-timer: Replace %Ld with %lld
  hangcheck-timer: fix coding style spacing

No functional changes were made to hangcheck logic.

Signed-off-by: Clint George <clintbgeorge@gmail.com>

---

Testing:
- Verified timer firing and margin detection using "hangtest" module that
i created (I will paste the code below for reference) and checked dmesg
logs for expected output: "Hangcheck: hangcheck value past margin!".
- Used Static Analysis tools
- Ensured module builds and inserts cleanly after changes.

Let me know any more tests need to be done on this module.

[] hangtest.c (testing module i created to test hangcheck-timer module):

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Clint George");
MODULE_DESCRIPTION("Hang test for testing hangcheck-timer");

static int hang_duration = 20;
module_param(hang_duration, int, 0644);

static int __init hangtest_init(void) {
    unsigned long timeout;

    printk(KERN_INFO "hangtest: Disabling interrupts for %d seconds...\n", hang_duration);

    local_irq_disable();
    preempt_disable();

    timeout = jiffies + (hang_duration * HZ);
    while (time_before(jiffies, timeout)) {
        cpu_relax();
        barrier();
    }

    preempt_enable();
    local_irq_enable();

    printk(KERN_INFO "hangtest: Interrupts re-enabled\n");
//    return 0;
    return -EINVAL; // Return error so module doesn't stay loaded
}

static void __exit hangtest_exit(void) {
    printk(KERN_INFO "hangtest: Exit\n");
}

module_init(hangtest_init);
module_exit(hangtest_exit);

 drivers/char/hangcheck-timer.c | 24 ++++++++++++++----------
 1 file changed, 14 insertions(+), 10 deletions(-)

-- 
2.43.0

[PATCH v2 1/3] hangcheck-timer: replace printk(KERN_CRIT) with pr_crit

[Clint George]

Replace printk(KERN_CRIT ...) with pr_crit(...) and printk() with
pr_debug(). The change aims to make logging more consistent and
readable.

Signed-off-by: Clint George <clintbgeorge@gmail.com>
---
 drivers/char/hangcheck-timer.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/char/hangcheck-timer.c b/drivers/char/hangcheck-timer.c
index 497fc167c..21ef8a6a0 100644
--- a/drivers/char/hangcheck-timer.c
+++ b/drivers/char/hangcheck-timer.c
@@ -126,23 +126,23 @@ static void hangcheck_fire(struct timer_list *unused)
 
 	if (tsc_diff > hangcheck_tsc_margin) {
 		if (hangcheck_dump_tasks) {
-			printk(KERN_CRIT "Hangcheck: Task state:\n");
+			pr_crit("Hangcheck: Task state:\n");
 #ifdef CONFIG_MAGIC_SYSRQ
 			handle_sysrq('t');
 #endif  /* CONFIG_MAGIC_SYSRQ */
 		}
 		if (hangcheck_reboot) {
-			printk(KERN_CRIT "Hangcheck: hangcheck is restarting the machine.\n");
+			pr_crit("Hangcheck: hangcheck is restarting the machine.\n");
 			emergency_restart();
 		} else {
-			printk(KERN_CRIT "Hangcheck: hangcheck value past margin!\n");
+			pr_crit("Hangcheck: hangcheck value past margin!\n");
 		}
 	}
 #if 0
 	/*
 	 * Enable to investigate delays in detail
 	 */
-	printk("Hangcheck: called %Ld ns since last time (%Ld ns overshoot)\n",
+	pr_debug("Hangcheck: called %Ld ns since last time (%Ld ns overshoot)\n",
 			tsc_diff, tsc_diff - hangcheck_tick*TIMER_FREQ);
 #endif
 	mod_timer(&hangcheck_ticktock, jiffies + (hangcheck_tick*HZ));
@@ -152,7 +152,7 @@ static void hangcheck_fire(struct timer_list *unused)
 
 static int __init hangcheck_init(void)
 {
-	printk("Hangcheck: starting hangcheck timer %s (tick is %d seconds, margin is %d seconds).\n",
+	pr_debug("Hangcheck: starting hangcheck timer %s (tick is %d seconds, margin is %d seconds).\n",
 	       VERSION_STR, hangcheck_tick, hangcheck_margin);
 	hangcheck_tsc_margin =
 		(unsigned long long)hangcheck_margin + hangcheck_tick;
@@ -168,7 +168,7 @@ static int __init hangcheck_init(void)
 static void __exit hangcheck_exit(void)
 {
 	timer_delete_sync(&hangcheck_ticktock);
-        printk("Hangcheck: Stopped hangcheck timer.\n");
+        pr_debug("Hangcheck: Stopped hangcheck timer.\n");
 }
 
 module_init(hangcheck_init);
-- 
2.43.0

[PATCH v2 2/3] hangcheck-timer: Replace %Ld with %lld

[Clint George]

Replace non-standard %Ld with %lld to ensure compliance with the kernel
coding style and potential formatting issues.

Signed-off-by: Clint George <clintbgeorge@gmail.com>
---
 drivers/char/hangcheck-timer.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/char/hangcheck-timer.c b/drivers/char/hangcheck-timer.c
index 21ef8a6a0..ff141fdb4 100644
--- a/drivers/char/hangcheck-timer.c
+++ b/drivers/char/hangcheck-timer.c
@@ -142,7 +142,7 @@ static void hangcheck_fire(struct timer_list *unused)
 	/*
 	 * Enable to investigate delays in detail
 	 */
-	pr_debug("Hangcheck: called %Ld ns since last time (%Ld ns overshoot)\n",
+	pr_debug("Hangcheck: called %lld ns since last time (%lld ns overshoot)\n",
 			tsc_diff, tsc_diff - hangcheck_tick*TIMER_FREQ);
 #endif
 	mod_timer(&hangcheck_ticktock, jiffies + (hangcheck_tick*HZ));
-- 
2.43.0

[PATCH v2 3/3] hangcheck-timer: fix coding style spacing

[Clint George]

Fix minor styling issues for proper compliance to the kernel coding
style.

Signed-off-by: Clint George <clintbgeorge@gmail.com>
---
 drivers/char/hangcheck-timer.c | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/drivers/char/hangcheck-timer.c b/drivers/char/hangcheck-timer.c
index ff141fdb4..231cbf7b3 100644
--- a/drivers/char/hangcheck-timer.c
+++ b/drivers/char/hangcheck-timer.c
@@ -69,7 +69,8 @@ MODULE_VERSION(VERSION_STR);
 static int __init hangcheck_parse_tick(char *str)
 {
 	int par;
-	if (get_option(&str,&par))
+
+	if (get_option(&str, &par))
 		hangcheck_tick = par;
 	return 1;
 }
@@ -77,7 +78,8 @@ static int __init hangcheck_parse_tick(char *str)
 static int __init hangcheck_parse_margin(char *str)
 {
 	int par;
-	if (get_option(&str,&par))
+
+	if (get_option(&str, &par))
 		hangcheck_margin = par;
 	return 1;
 }
@@ -85,7 +87,8 @@ static int __init hangcheck_parse_margin(char *str)
 static int __init hangcheck_parse_reboot(char *str)
 {
 	int par;
-	if (get_option(&str,&par))
+
+	if (get_option(&str, &par))
 		hangcheck_reboot = par;
 	return 1;
 }
@@ -93,7 +96,8 @@ static int __init hangcheck_parse_reboot(char *str)
 static int __init hangcheck_parse_dump_tasks(char *str)
 {
 	int par;
-	if (get_option(&str,&par))
+
+	if (get_option(&str, &par))
 		hangcheck_dump_tasks = par;
 	return 1;
 }
@@ -168,7 +172,7 @@ static int __init hangcheck_init(void)
 static void __exit hangcheck_exit(void)
 {
 	timer_delete_sync(&hangcheck_ticktock);
-        pr_debug("Hangcheck: Stopped hangcheck timer.\n");
+	pr_debug("Hangcheck: Stopped hangcheck timer.\n");
 }
 
 module_init(hangcheck_init);
-- 
2.43.0