softlockup: allow panic on lockup

allow users to configure the softlockup detector to generate a panic
instead of a warning message.

high-availability systems might opt for this strict method (combined
with panic_timeout= boot option/sysctl), instead of generating
softlockup warnings ad infinitum.

also, automated tests work better if the system reboots reliably (into
a safe kernel) in case of a lockup.

The full spectrum of configurability is supported: boot option, sysctl
option and Kconfig option.

it's default-disabled.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 25 insertions, 1 deletions

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index d2099f41aa1e..509ae35a9ef5 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -147,7 +147,7 @@ config DETECT_SOFTLOCKUP
         help
           Say Y here to enable the kernel to detect "soft lockups",
           which are bugs that cause the kernel to loop in kernel
-          mode for more than 10 seconds, without giving other tasks a
+          mode for more than 60 seconds, without giving other tasks a
           chance to run.
 
           When a soft-lockup is detected, the kernel will print the
@@ -159,6 +159,30 @@ config DETECT_SOFTLOCKUP
            can be detected via the NMI-watchdog, on platforms that
            support it.)
 
+config BOOTPARAM_SOFTLOCKUP_PANIC
+        bool "Panic (Reboot) On Soft Lockups"
+        depends on DETECT_SOFTLOCKUP
+        help
+          Say Y here to enable the kernel to panic on "soft lockups",
+          which are bugs that cause the kernel to loop in kernel
+          mode for more than 60 seconds, without giving other tasks a
+          chance to run.
+
+          The panic can be used in combination with panic_timeout,
+          to cause the system to reboot automatically after a
+          lockup has been detected. This feature is useful for
+          high-availability systems that have uptime guarantees and
+          where a lockup must be resolved ASAP.
+
+          Say N if unsure.
+
+config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE
+        int
+        depends on DETECT_SOFTLOCKUP
+        range 0 1
+        default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC
+        default 1 if BOOTPARAM_SOFTLOCKUP_PANIC
+
 config SCHED_DEBUG
         bool "Collect scheduler debugging info"
         depends on DEBUG_KERNEL && PROC_FS