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| author | Petr Mladek <pmladek@suse.com> | 2019-10-24 13:49:26 +0200 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2020-01-16 14:52:48 +0100 |
| commit | 3a51449b7959f68cc45abe67298e40c7eb57167b (patch) | |
| tree | bd147ead9447bfcb03711261333e3a9f15c17dfc /kernel/watchdog.c | |
| parent | watchdog: Remove soft_lockup_hrtimer_cnt and related code (diff) | |
| download | linux-3a51449b7959f68cc45abe67298e40c7eb57167b.tar.xz linux-3a51449b7959f68cc45abe67298e40c7eb57167b.zip | |
watchdog/softlockup: Remove obsolete check of last reported task
commit 9cf57731b63e ("watchdog/softlockup: Replace "watchdog/%u" threads
with cpu_stop_work") ensures that the watchdog is reliably touched during
a task switch.
As a result the check for an unnoticed task switch is not longer needed.
Remove the relevant code, which effectively reverts commit b1a8de1f5343
("softlockup: make detector be aware of task switch of processes hogging
cpu")
Signed-off-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Ziljstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20191024114928.15377-2-pmladek@suse.com
Diffstat (limited to 'kernel/watchdog.c')
| -rw-r--r-- | kernel/watchdog.c | 18 |
1 files changed, 1 insertions, 17 deletions
diff --git a/kernel/watchdog.c b/kernel/watchdog.c index 0621301ae8cf..e3774e9625b7 100644 --- a/kernel/watchdog.c +++ b/kernel/watchdog.c @@ -173,7 +173,6 @@ static DEFINE_PER_CPU(struct hrtimer, watchdog_hrtimer); static DEFINE_PER_CPU(bool, softlockup_touch_sync); static DEFINE_PER_CPU(bool, soft_watchdog_warn); static DEFINE_PER_CPU(unsigned long, hrtimer_interrupts); -static DEFINE_PER_CPU(struct task_struct *, softlockup_task_ptr_saved); static DEFINE_PER_CPU(unsigned long, hrtimer_interrupts_saved); static unsigned long soft_lockup_nmi_warn; @@ -413,22 +412,8 @@ static enum hrtimer_restart watchdog_timer_fn(struct hrtimer *hrtimer) return HRTIMER_RESTART; /* only warn once */ - if (__this_cpu_read(soft_watchdog_warn) == true) { - /* - * When multiple processes are causing softlockups the - * softlockup detector only warns on the first one - * because the code relies on a full quiet cycle to - * re-arm. The second process prevents the quiet cycle - * and never gets reported. Use task pointers to detect - * this. - */ - if (__this_cpu_read(softlockup_task_ptr_saved) != - current) { - __this_cpu_write(soft_watchdog_warn, false); - __touch_watchdog(); - } + if (__this_cpu_read(soft_watchdog_warn) == true) return HRTIMER_RESTART; - } if (softlockup_all_cpu_backtrace) { /* Prevent multiple soft-lockup reports if one cpu is already @@ -444,7 +429,6 @@ static enum hrtimer_restart watchdog_timer_fn(struct hrtimer *hrtimer) pr_emerg("BUG: soft lockup - CPU#%d stuck for %us! [%s:%d]\n", smp_processor_id(), duration, current->comm, task_pid_nr(current)); - __this_cpu_write(softlockup_task_ptr_saved, current); print_modules(); print_irqtrace_events(current); if (regs) |