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>
Format: [state][,regs][,debounce][,die]
nmi_watchdog= [KNL,BUGS=X86] Debugging features for SMP kernels
Format: [state][,regs][,debounce][,die]
nmi_watchdog= [KNL,BUGS=X86] Debugging features for SMP kernels
+ Format: [panic,][nopanic,][num]
Valid num: 0
0 - turn nmi_watchdog off
When panic is specified, panic when an NMI watchdog
Valid num: 0
0 - turn nmi_watchdog off
When panic is specified, panic when an NMI watchdog
+ timeout occurs (or 'nopanic' to override the opposite
+ default).
This is useful when you use a panic=... timeout and
need the box quickly up again.
This is useful when you use a panic=... timeout and
need the box quickly up again.
* Should we panic when a soft-lockup or hard-lockup occurs:
*/
#ifdef CONFIG_HARDLOCKUP_DETECTOR
* Should we panic when a soft-lockup or hard-lockup occurs:
*/
#ifdef CONFIG_HARDLOCKUP_DETECTOR
-static int hardlockup_panic;
+static int hardlockup_panic =
+ CONFIG_BOOTPARAM_HARDLOCKUP_PANIC_VALUE;
static int __init hardlockup_panic_setup(char *str)
{
if (!strncmp(str, "panic", 5))
hardlockup_panic = 1;
static int __init hardlockup_panic_setup(char *str)
{
if (!strncmp(str, "panic", 5))
hardlockup_panic = 1;
+ else if (!strncmp(str, "nopanic", 7))
+ hardlockup_panic = 0;
else if (!strncmp(str, "0", 1))
watchdog_enabled = 0;
return 1;
else if (!strncmp(str, "0", 1))
watchdog_enabled = 0;
return 1;
def_bool LOCKUP_DETECTOR && PERF_EVENTS && HAVE_PERF_EVENTS_NMI && \
!ARCH_HAS_NMI_WATCHDOG
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
config BOOTPARAM_SOFTLOCKUP_PANIC
bool "Panic (Reboot) On Soft Lockups"
depends on LOCKUP_DETECTOR