The patch titled
Subject: watchdog: trigger all-cpu backtrace when locked up and going to panic
has been added to the -mm tree. Its filename is
watchdog-trigger-all-cpu-backtrace-when-locked-up-and-going-to-panic.patch
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*** Remember to use Documentation/SubmitChecklist when testing your code ***
The -mm tree is included into linux-next and is updated
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------------------------------------------------------
From: Sasha Levin <sasha.levin@xxxxxxxxxx>
Subject: watchdog: trigger all-cpu backtrace when locked up and going to panic
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.levin@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/watchdog.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)
diff -puN kernel/watchdog.c~watchdog-trigger-all-cpu-backtrace-when-locked-up-and-going-to-panic kernel/watchdog.c
--- a/kernel/watchdog.c~watchdog-trigger-all-cpu-backtrace-when-locked-up-and-going-to-panic
+++ a/kernel/watchdog.c
@@ -239,10 +239,12 @@ static void watchdog_overflow_callback(s
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_tim
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);
_
Patches currently in -mm which might be from sasha.levin@xxxxxxxxxx are
linux-next.patch
watchdog-trigger-all-cpu-backtrace-when-locked-up-and-going-to-panic.patch
slub-drop-mutex-before-deleting-sysfs-entry.patch
mm-augment-vma-rbtree-with-rb_subtree_gap-ensure-safe-rb_subtree_gap-update-when-inserting-new-vma.patch
mm-augment-vma-rbtree-with-rb_subtree_gap-ensure-safe-rb_subtree_gap-update-when-removing-vma.patch
mm-augment-vma-rbtree-with-rb_subtree_gap--debug-code-to-verify-rb_subtree_gap-updates-are-safe.patch
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