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

Clint George
2025-11-05T14:05:51Z

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