Send an NMI to all CPUs when a lockup is detected and the lockup
watchdog code is configured to panic. This gives us a fairly uptodate
snapshot of all CPUs in the system.
This lets us get stack trace of all CPUs which makes life easier
trying to debug a deadlock, and the NMI doesn't change anything
since the next step is a kernel panic.
Signed-off-by: Sasha Levin <sasha.le...@oracle.com>
---
kernel/watchdog.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)
diff --git a/kernel/watchdog.c b/kernel/watchdog.c
index 9d4c8d5..26a5f88 100644
--- a/kernel/watchdog.c
+++ b/kernel/watchdog.c
@@ -239,10 +239,12 @@ static void watchdog_overflow_callback(struct perf_event
*event,
if (__this_cpu_read(hard_watchdog_warn) == true)
return;
- if (hardlockup_panic)
+ if (hardlockup_panic) {
+ trigger_all_cpu_backtrace();
panic("Watchdog detected hard LOCKUP on cpu %d",
this_cpu);
- else
+ } else {
WARN(1, "Watchdog detected hard LOCKUP on cpu %d",
this_cpu);
+ }
__this_cpu_write(hard_watchdog_warn, true);
return;
@@ -323,8 +325,10 @@ static enum hrtimer_restart watchdog_timer_fn(struct
hrtimer *hrtimer)
else
dump_stack();
- if (softlockup_panic)
+ if (softlockup_panic) {
+ trigger_all_cpu_backtrace();
panic("softlockup: hung tasks");
+ }
__this_cpu_write(soft_watchdog_warn, true);
} else
__this_cpu_write(soft_watchdog_warn, false);
--
1.8.0
--
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