diff options
| author | Don Zickus <dzickus@redhat.com> | 2011-03-22 16:34:16 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2011-03-22 17:44:12 -0700 |
| commit | fef2c9bc1b54c0261324a96e948c0b849796e896 (patch) | |
| tree | a4dd2733621d9fe1f8ec65d9ef30867ed09b640f | |
| parent | b1b5f65e53af770ede22c113e249de2f6fa53706 (diff) | |
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>
| -rw-r--r-- | Documentation/kernel-parameters.txt | 5 | ||||
| -rw-r--r-- | kernel/watchdog.c | 5 | ||||
| -rw-r--r-- | lib/Kconfig.debug | 17 |
3 files changed, 24 insertions, 3 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index a3b688287a8..e9261e938f6 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -1597,11 +1597,12 @@ bytes respectively. Such letter suffixes can also be entirely omitted. Format: [state][,regs][,debounce][,die] nmi_watchdog= [KNL,BUGS=X86] Debugging features for SMP kernels - Format: [panic,][num] + Format: [panic,][nopanic,][num] Valid num: 0 0 - turn nmi_watchdog off When panic is specified, panic when an NMI watchdog - timeout occurs. + 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. diff --git a/kernel/watchdog.c b/kernel/watchdog.c index 18bb15776c5..054a67cca9d 100644 --- a/kernel/watchdog.c +++ b/kernel/watchdog.c @@ -48,12 +48,15 @@ static DEFINE_PER_CPU(struct perf_event *, watchdog_ev); * 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; + else if (!strncmp(str, "nopanic", 7)) + hardlockup_panic = 0; else if (!strncmp(str, "0", 1)) watchdog_enabled = 0; return 1; diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 191c5c4c89f..fb0afeff943 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 |