linux/kernel
Bjørn Mork 3935e89505 watchdog: Fix disable/enable regression
Commit 8d4516904b ("watchdog: Fix CPU hotplug regression") causes an
oops or hard lockup when doing

 echo 0 > /proc/sys/kernel/nmi_watchdog
 echo 1 > /proc/sys/kernel/nmi_watchdog

and the kernel is booted with nmi_watchdog=1 (default)

Running laptop-mode-tools and disconnecting/connecting AC power will
cause this to trigger, making it a common failure scenario on laptops.

Instead of bailing out of watchdog_disable() when !watchdog_enabled we
can initialize the hrtimer regardless of watchdog_enabled status.  This
makes it safe to call watchdog_disable() in the nmi_watchdog=0 case,
without the negative effect on the enabled => disabled => enabled case.

All these tests pass with this patch:
- nmi_watchdog=1
  echo 0 > /proc/sys/kernel/nmi_watchdog
  echo 1 > /proc/sys/kernel/nmi_watchdog

- nmi_watchdog=0
  echo 0 > /sys/devices/system/cpu/cpu1/online

- nmi_watchdog=0
  echo mem > /sys/power/state

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=51661

Cc: <stable@vger.kernel.org> # v3.7
Cc: Norbert Warmuth <nwarmuth@t-online.de>
Cc: Joseph Salisbury <joseph.salisbury@canonical.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Bjørn Mork <bjorn@mork.no>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-19 12:10:33 -08:00
..
debug KGDB/KDB fixes and cleanups 2012-10-13 11:16:58 +09:00
events Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2012-12-17 15:44:47 -08:00
gcov
irq irq: tsk->comm is an array 2012-12-18 15:02:11 -08:00
power Merge branch 'for-3.8' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup 2012-12-12 08:18:24 -08:00
sched Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2012-12-17 15:44:47 -08:00
time Merge tag 'kvm-3.8-1' of git://git.kernel.org/pub/scm/virt/kvm/kvm 2012-12-13 15:31:08 -08:00
trace Merge branch 'tip/perf/core-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace 2012-12-18 12:28:39 -08:00
.gitignore
acct.c vfs: make path_openat take a struct filename pointer 2012-10-12 20:15:09 -04:00
async.c [SCSI] async: make async_synchronize_full() flush all work regardless of domain 2012-07-20 09:07:37 +01:00
audit_tree.c audit: clean up refcounting in audit-tree 2012-08-15 12:55:22 +02:00
audit_watch.c audit: optimize audit_compare_dname_path 2012-10-12 00:32:02 -04:00
audit.c fs: handle failed audit_log_start properly 2012-10-09 23:33:37 -04:00
audit.h audit: optimize audit_compare_dname_path 2012-10-12 00:32:02 -04:00
auditfilter.c audit: optimize audit_compare_dname_path 2012-10-12 00:32:02 -04:00
auditsc.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal 2012-12-12 12:22:13 -08:00
backtracetest.c
bounds.c
capability.c
cgroup_freezer.c cgroup: rename ->create/post_create/pre_destroy/destroy() to ->css_alloc/online/offline/free() 2012-11-19 08:13:38 -08:00
cgroup.c Merge branch 'akpm' (Andrew's patch-bomb) 2012-12-17 20:58:12 -08:00
compat.c compat: generic compat_sys_sched_rr_get_interval() implementation 2012-12-17 17:15:18 -08:00
configs.c
context_tracking.c context_tracking: New context tracking susbsystem 2012-11-30 11:40:07 -08:00
cpu_pm.c kernel/cpu_pm.c: fix various typos 2012-05-31 17:49:27 -07:00
cpu.c Merge branch 'x86-bsp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2012-12-11 19:56:33 -08:00
cpuset.c cpuset: use N_MEMORY instead N_HIGH_MEMORY 2012-12-12 17:38:32 -08:00
crash_dump.c
cred.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2012-12-18 10:55:28 -08:00
delayacct.c
dma.c
elfcore.c
exec_domain.c
exit.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2012-12-17 15:44:47 -08:00
extable.c
fork.c fork: protect architectures where THREAD_SIZE >= PAGE_SIZE against fork bombs 2012-12-18 15:02:13 -08:00
freezer.c freezer: change ptrace_stop/do_signal_stop to use freezable_schedule() 2012-10-26 14:27:49 -07:00
futex_compat.c
futex.c futex: avoid wake_futex() for a PI futex_q 2012-11-26 17:41:24 -08:00
groups.c
hrtimer.c hrtimer: Update hrtimer base offsets each hrtimer_interrupt 2012-07-11 23:34:39 +02:00
hung_task.c
irq_work.c
itimer.c
jump_label.c jump_label: Export jump_label_rate_limit() 2012-08-06 19:00:35 +03:00
kallsyms.c
kcmp.c syscalls, x86: add __NR_kcmp syscall 2012-05-31 17:49:32 -07:00
Kconfig.freezer
Kconfig.hz
Kconfig.locks locking: Adjust spin lock inlining Kconfig options 2012-09-13 17:56:13 +02:00
Kconfig.preempt
kexec.c kdump: remove unneeded include 2012-10-06 03:05:19 +09:00
kfifo.c
kmod.c infrastructure for saner ret_from_kernel_thread semantics 2012-10-12 13:35:07 -04:00
kprobes.c kprobes/x86: Fix to support jprobes on ftrace-based kprobe 2012-09-13 22:52:11 -04:00
ksysfs.c Merge branch 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2012-12-11 18:10:49 -08:00
kthread.c kthread: use N_MEMORY instead N_HIGH_MEMORY 2012-12-12 17:38:33 -08:00
latencytop.c
lglock.c brlocks/lglocks: turn into functions 2012-05-29 23:28:41 -04:00
lockdep_internals.h
lockdep_proc.c lockdep: Use KSYM_NAME_LEN'ed buffer for __get_key_name() 2012-10-24 12:39:09 +02:00
lockdep_states.h
lockdep.c lockdep: Check if nested lock is actually held 2012-09-13 17:00:44 +02:00
Makefile Nothing all that exciting; a new module-from-fd syscall for those who want 2012-12-19 07:55:08 -08:00
modsign_certificate.S MODSIGN: Avoid using .incbin in C source 2012-12-14 13:06:44 +10:30
modsign_pubkey.c MODSIGN: Avoid using .incbin in C source 2012-12-14 13:06:44 +10:30
module_signing.c MODSIGN: Don't use enum-type bitfields in module signature info block 2012-12-05 11:27:24 +10:30
module-internal.h MODSIGN: Move the magic string to the end of a module and eliminate the search 2012-10-19 17:30:40 -07:00
module.c Nothing all that exciting; a new module-from-fd syscall for those who want 2012-12-19 07:55:08 -08:00
mutex-debug.c
mutex-debug.h
mutex.c
mutex.h
notifier.c
nsproxy.c userns: Implement unshare of the user namespace 2012-11-20 04:18:14 -08:00
padata.c padata: use __this_cpu_read per-cpu helper 2012-12-06 17:16:23 +08:00
panic.c panic: fix a possible deadlock in panic() 2012-07-30 17:25:13 -07:00
params.c
pid_namespace.c userns: Require CAP_SYS_ADMIN for most uses of setns. 2012-12-14 16:12:03 -08:00
pid.c Merge branch 'akpm' (Andrew's patch-bomb) 2012-12-17 20:58:12 -08:00
posix-cpu-timers.c cputime: Move thread_group_cputime() to sched code 2012-11-28 17:07:38 +01:00
posix-timers.c
printk.c printk: boot_delay should only affect output 2012-12-17 17:15:13 -08:00
profile.c propagate name change to comments in kernel source 2012-12-06 10:39:54 +01:00
ptrace.c Merge branch 'akpm' (Andrew's patch-bomb) 2012-12-17 20:58:12 -08:00
range.c
rcu.h rcu: Add a module parameter to force use of expedited RCU primitives 2012-10-23 14:54:08 -07:00
rcupdate.c rcu: Add a module parameter to force use of expedited RCU primitives 2012-10-23 14:54:08 -07:00
rcutiny_plugin.h rcu: Add a module parameter to force use of expedited RCU primitives 2012-10-23 14:54:08 -07:00
rcutiny.c rcu: Fix TINY_RCU rcu_is_cpu_rrupt_from_idle check 2012-11-13 14:08:34 -08:00
rcutorture.c Merge branches 'urgent.2012.10.27a', 'doc.2012.11.16a', 'fixes.2012.11.13a', 'srcu.2012.10.27a', 'stall.2012.11.13a', 'tracing.2012.11.08a' and 'idle.2012.10.24a' into HEAD 2012-11-16 09:59:58 -08:00
rcutree_plugin.h rcu: Separate accounting of callbacks from callback-free CPUs 2012-11-16 10:05:57 -08:00
rcutree_trace.c rcu: Separate accounting of callbacks from callback-free CPUs 2012-11-16 10:05:57 -08:00
rcutree.c context_tracking: New context tracking susbsystem 2012-11-30 11:40:07 -08:00
rcutree.h rcu: Separate accounting of callbacks from callback-free CPUs 2012-11-16 10:05:57 -08:00
relay.c splice: fix racy pipe->buffers uses 2012-06-13 21:16:42 +02:00
res_counter.c res_counter: return amount of charges after res_counter_uncharge() 2012-12-18 15:02:12 -08:00
resource.c kernel/resource.c: fix stack overflow in __reserve_region_with_split() 2012-10-06 03:05:31 +09:00
rtmutex_common.h
rtmutex-debug.c
rtmutex-debug.h
rtmutex-tester.c
rtmutex.c
rtmutex.h
rwsem.c
seccomp.c seccomp: Make syscall skipping and nr changes more consistent 2012-10-02 21:14:29 +10:00
semaphore.c
signal.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2012-12-17 15:44:47 -08:00
smp.c smp: Remove ipi_call_lock[_irq]()/ipi_call_unlock[_irq]() 2012-06-05 17:27:14 +02:00
smpboot.c hotplug: Fix UP bug in smpboot hotplug code 2012-08-13 17:01:07 +02:00
smpboot.h smpboot: Provide infrastructure for percpu hotplug threads 2012-08-13 17:01:07 +02:00
softirq.c cputime: Specialize irq vtime hooks 2012-10-29 21:31:32 +01:00
spinlock.c
srcu.c Merge branches 'urgent.2012.10.27a', 'doc.2012.11.16a', 'fixes.2012.11.13a', 'srcu.2012.10.27a', 'stall.2012.11.13a', 'tracing.2012.11.08a' and 'idle.2012.10.24a' into HEAD 2012-11-16 09:59:58 -08:00
stacktrace.c
stop_machine.c
sys_ni.c module: add syscall to load module from fd 2012-12-14 13:05:22 +10:30
sys.c cputime: Rename thread_group_times to thread_group_cputime_adjusted 2012-11-28 17:07:57 +01:00
sysctl_binary.c pidns: Use task_active_pid_ns where appropriate 2012-11-19 05:59:09 -08:00
sysctl.c Automatic NUMA Balancing V11 2012-12-16 15:18:08 -08:00
task_work.c task_work: task_work_add() should not succeed after exit_task_work() 2012-09-13 16:47:34 +02:00
taskstats.c taskstats: cgroupstats_user_cmd() may leak on error 2012-10-06 03:05:31 +09:00
test_kprobes.c
time.c time: Move update_vsyscall definitions to timekeeper_internal.h 2012-09-24 12:38:06 -04:00
timeconst.pl
timer.c timers: Fix endless looping between cascade() and internal_add_timer() 2012-10-09 21:27:14 +02:00
tracepoint.c
tsacct.c userns: Convert taskstats to handle the user and pid namespaces. 2012-09-18 01:01:32 -07:00
uid16.c
up.c
user_namespace.c userns: Fix typo in description of the limitation of userns_install 2012-12-14 18:36:36 -08:00
user-return-notifier.c
user.c proc: Usable inode numbers for the namespace file descriptors. 2012-11-20 04:19:49 -08:00
utsname_sysctl.c
utsname.c userns: Require CAP_SYS_ADMIN for most uses of setns. 2012-12-14 16:12:03 -08:00
wait.c propagate name change to comments in kernel source 2012-12-06 10:39:54 +01:00
watchdog.c watchdog: Fix disable/enable regression 2012-12-19 12:10:33 -08:00
workqueue_sched.h
workqueue.c Merge branch 'for-3.8' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq 2012-12-12 08:15:13 -08:00