diff options
| author | Mandeep Singh Baines <msb@google.com> | 2009-01-12 21:15:17 -0800 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-01-14 11:48:07 +0100 |
| commit | baf48f6577e581a9adb8fe849dc80e24b21d171d (patch) | |
| tree | 279e54b7374a9c52025ded4f9bb718e5382b0340 | |
| parent | e4fa4c97016037620f9dc8bafe03e1086b665b4c (diff) | |
softlock: fix false panic which can occur if softlockup_thresh is reduced
At run-time, if softlockup_thresh is changed to a much lower value,
touch_timestamp is likely to be much older than the new softlock_thresh.
This will cause a false softlockup to be detected. If softlockup_panic
is enabled, the system will panic.
The fix is to touch all watchdogs before changing softlockup_thresh.
Signed-off-by: Mandeep Singh Baines <msb@google.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
| -rw-r--r-- | include/linux/sched.h | 3 | ||||
| -rw-r--r-- | kernel/softlockup.c | 9 | ||||
| -rw-r--r-- | kernel/sysctl.c | 2 |
3 files changed, 13 insertions, 1 deletions
diff --git a/include/linux/sched.h b/include/linux/sched.h index 4cae9b81a1f..54cbabf3b87 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -293,6 +293,9 @@ extern void sched_show_task(struct task_struct *p); extern void softlockup_tick(void); extern void touch_softlockup_watchdog(void); extern void touch_all_softlockup_watchdogs(void); +extern int proc_dosoftlockup_thresh(struct ctl_table *table, int write, + struct file *filp, void __user *buffer, + size_t *lenp, loff_t *ppos); extern unsigned int softlockup_panic; extern unsigned long sysctl_hung_task_check_count; extern unsigned long sysctl_hung_task_timeout_secs; diff --git a/kernel/softlockup.c b/kernel/softlockup.c index d9188c66278..85d5a245510 100644 --- a/kernel/softlockup.c +++ b/kernel/softlockup.c @@ -16,6 +16,7 @@ #include <linux/lockdep.h> #include <linux/notifier.h> #include <linux/module.h> +#include <linux/sysctl.h> #include <asm/irq_regs.h> @@ -88,6 +89,14 @@ void touch_all_softlockup_watchdogs(void) } EXPORT_SYMBOL(touch_all_softlockup_watchdogs); +int proc_dosoftlockup_thresh(struct ctl_table *table, int write, + struct file *filp, void __user *buffer, + size_t *lenp, loff_t *ppos) +{ + touch_all_softlockup_watchdogs(); + return proc_dointvec_minmax(table, write, filp, buffer, lenp, ppos); +} + /* * This callback runs from the timer interrupt, and checks * whether the watchdog thread has hung or not: diff --git a/kernel/sysctl.c b/kernel/sysctl.c index 89d74436318..596dc31a711 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -800,7 +800,7 @@ static struct ctl_table kern_table[] = { .data = &softlockup_thresh, .maxlen = sizeof(int), .mode = 0644, - .proc_handler = &proc_dointvec_minmax, + .proc_handler = &proc_dosoftlockup_thresh, .strategy = &sysctl_intvec, .extra1 = &neg_one, .extra2 = &sixty, |