kernel/watchdog.c: allow hardlockup to panic by default

When a cpu is considered stuck, instead of limping along and just printing
a warning, it is sometimes preferred to just panic, let kdump capture the
vmcore and reboot.  This gets the machine back into a stable state quickly
while saving the info that got it into a stuck state to begin with.

Add a Kconfig option to allow users to set the hardlockup to panic
by default.  Also add in a 'nmi_watchdog=nopanic' to override this.

[akpm@linux-foundation.org: fix strncmp length]
Signed-off-by: Don Zickus <dzickus@redhat.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Reviewed-by: WANG Cong <xiyou.wangcong@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 17 insertions, 0 deletions

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 191c5c4c89fc..fb0afeff9436 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -171,6 +171,23 @@ config HARDLOCKUP_DETECTOR
         def_bool LOCKUP_DETECTOR && PERF_EVENTS && HAVE_PERF_EVENTS_NMI && \
                  !ARCH_HAS_NMI_WATCHDOG
 
+config BOOTPARAM_HARDLOCKUP_PANIC
+        bool "Panic (Reboot) On Hard Lockups"
+        depends on LOCKUP_DETECTOR
+        help
+          Say Y here to enable the kernel to panic on "hard lockups",
+          which are bugs that cause the kernel to loop in kernel
+          mode with interrupts disabled for more than 60 seconds.
+
+          Say N if unsure.
+
+config BOOTPARAM_HARDLOCKUP_PANIC_VALUE
+        int
+        depends on LOCKUP_DETECTOR
+        range 0 1
+        default 0 if !BOOTPARAM_HARDLOCKUP_PANIC
+        default 1 if BOOTPARAM_HARDLOCKUP_PANIC
+
 config BOOTPARAM_SOFTLOCKUP_PANIC
         bool "Panic (Reboot) On Soft Lockups"
         depends on LOCKUP_DETECTOR