[PATCH 2/2] RFC: soft/hardlookup: taint kernel

[Daniel Vetter <daniel.vetter@ffwll.ch>]

There's the soft/hardlookup_panic sysctls, but that's a bit an extreme
measure. As a fallback taint at least the machine.

Our CI uses this to decide when a reboot is necessary, plus to figure
out whether the kernel is still happy.

Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Valdis Kletnieks <valdis.kletnieks@vt.edu>
Cc: Laurence Oberman <loberman@redhat.com>
Cc: Vincent Whitchurch <vincent.whitchurch@axis.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: Sinan Kaya <okaya@kernel.org>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
---
 kernel/watchdog.c     | 2 ++
 kernel/watchdog_hld.c | 2 ++
 2 files changed, 4 insertions(+)

diff --git a/kernel/watchdog.c b/kernel/watchdog.c
index 6a5787233113..de7a60503517 100644
--- a/kernel/watchdog.c
+++ b/kernel/watchdog.c
@@ -469,6 +469,8 @@ static enum hrtimer_restart watchdog_timer_fn(struct hrtimer *hrtimer)
 		add_taint(TAINT_SOFTLOCKUP, LOCKDEP_STILL_OK);
 		if (softlockup_panic)
 			panic("softlockup: hung tasks");
+		else
+			add_taint(TAINT_WARN, LOCKDEP_STILL_OK);
 		__this_cpu_write(soft_watchdog_warn, true);
 	} else
 		__this_cpu_write(soft_watchdog_warn, false);
diff --git a/kernel/watchdog_hld.c b/kernel/watchdog_hld.c
index 247bf0b1582c..cce46cf75d76 100644
--- a/kernel/watchdog_hld.c
+++ b/kernel/watchdog_hld.c
@@ -154,6 +154,8 @@ static void watchdog_overflow_callback(struct perf_event *event,
 
 		if (hardlockup_panic)
 			nmi_panic(regs, "Hard LOCKUP");
+		else
+			add_taint(TAINT_WARN, LOCKDEP_STILL_OK);
 
 		__this_cpu_write(hard_watchdog_warn, true);
 		return;
-- 
2.20.1