kernel_optimize_test/kernel
Don Zickus b94f51183b kernel/watchdog: prevent false hardlockup on overloaded system
On an overloaded system, it is possible that a change in the watchdog
threshold can be delayed long enough to trigger a false positive.

This can easily be achieved by having a cpu spinning indefinitely on a
task, while another cpu updates watchdog threshold.

What happens is while trying to park the watchdog threads, the hrtimers
on the other cpus trigger and reprogram themselves with the new slower
watchdog threshold.  Meanwhile, the nmi watchdog is still programmed
with the old faster threshold.

Because the one cpu is blocked, it prevents the thread parking on the
other cpus from completing, which is needed to shutdown the nmi watchdog
and reprogram it correctly.  As a result, a false positive from the nmi
watchdog is reported.

Fix this by setting a park_in_progress flag to block all lockups until
the parking is complete.

Fix provided by Ulrich Obergfell.

[akpm@linux-foundation.org: s/park_in_progress/watchdog_park_in_progress/]
Link: http://lkml.kernel.org/r/1481041033-192236-1-git-send-email-dzickus@redhat.com
Signed-off-by: Don Zickus <dzickus@redhat.com>
Reviewed-by: Aaron Tomlin <atomlin@redhat.com>
Cc: Ulrich Obergfell <uobergfe@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-01-24 16:26:14 -08:00
..
bpf bpf: rework prog_digest into prog_tag 2017-01-16 14:03:31 -05:00
configs
debug kdb: call vkdb_printf() from vprintk_default() only when wanted 2016-12-14 16:04:08 -08:00
events perf/x86/intel: Account interrupts for PEBS errors 2017-01-14 11:06:49 +01:00
gcov
irq genirq/affinity: Fix node generation from cpumask 2016-12-15 12:32:35 +01:00
livepatch
locking Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
power Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
printk Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
rcu rcu: Narrow early boot window of illegal synchronous grace periods 2017-01-14 21:23:48 -08:00
sched ktime: Cleanup ktime_set() usage 2016-12-25 17:21:22 +01:00
time nohz: Fix collision between tick and other hrtimers 2017-01-11 10:41:33 +01:00
trace clocksource: Use a plain u64 instead of cycle_t 2016-12-25 11:04:12 +01:00
.gitignore
acct.c
async.c
audit_fsnotify.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2016-12-17 18:44:00 -08:00
audit_tree.c Merge branch 'stable-4.10' of git://git.infradead.org/users/pcmoore/audit 2017-01-05 23:06:06 -08:00
audit_watch.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2016-12-17 18:44:00 -08:00
audit.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2016-12-17 18:44:00 -08:00
audit.h
auditfilter.c
auditsc.c Merge branch 'stable-4.10' of git://git.infradead.org/users/pcmoore/audit 2016-12-14 14:06:40 -08:00
backtracetest.c
bounds.c
capability.c capability: export has_capability 2017-01-12 07:01:56 -07:00
cgroup_freezer.c
cgroup_pids.c
cgroup.c
compat.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
configs.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
context_tracking.c
cpu_pm.c
cpu.c cpu/hotplug: Remove unused but set variable in _cpu_down() 2017-01-18 11:55:09 +01:00
cpuset.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
crash_dump.c
cred.c
delayacct.c
dma.c
elfcore.c
exec_domain.c
exit.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
extable.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
fork.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
freezer.c
futex_compat.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
futex.c ktime: Get rid of the union 2016-12-25 17:21:22 +01:00
groups.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
hung_task.c hung_task: decrement sysctl_hung_task_warnings only if it is positive 2016-12-12 18:55:09 -08:00
irq_work.c
jump_label.c jump_labels: API for flushing deferred jump label updates 2017-01-12 14:33:16 +01:00
kallsyms.c
kcmp.c
Kconfig.freezer
Kconfig.hz
Kconfig.locks
Kconfig.preempt
kcov.c kcov: make kcov work properly with KASLR enabled 2016-12-20 09:48:47 -08:00
kexec_core.c kexec: add cond_resched into kimage_alloc_crash_control_pages 2016-12-14 16:04:07 -08:00
kexec_file.c ima: on soft reboot, save the measurement list 2016-12-20 09:48:44 -08:00
kexec_internal.h
kexec.c
kmod.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
kprobes.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
ksysfs.c
kthread.c kthread: add __printf attributes 2016-12-12 18:55:06 -08:00
latencytop.c
Makefile Merge branch 'akpm' (patches from Andrew) 2016-12-14 17:25:18 -08:00
membarrier.c
memremap.c mm: fix devm_memremap_pages crash, use mem_hotplug_{begin, done} 2017-01-10 18:31:54 -08:00
module_signing.c
module-internal.h
module.c taint/module: Fix problems when out-of-kernel driver defines true or false 2017-01-17 10:56:45 -08:00
notifier.c
nsproxy.c
padata.c
panic.c taint/module: Fix problems when out-of-kernel driver defines true or false 2017-01-17 10:56:45 -08:00
params.c
pid_namespace.c pid: fix lockdep deadlock warning due to ucount_lock 2017-01-10 13:34:56 +13:00
pid.c
profile.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
ptrace.c
range.c
reboot.c
relay.c relay: check array offset before using it 2016-12-14 16:04:08 -08:00
resource.c
seccomp.c Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security 2016-12-14 13:57:44 -08:00
signal.c signal: protect SIGNAL_UNKILLABLE from unintentional clearing. 2017-01-10 18:31:55 -08:00
smp.c
smpboot.c
smpboot.h
softirq.c
stacktrace.c
stop_machine.c
sys_ni.c move aio compat to fs/aio.c 2016-12-22 22:58:37 -05:00
sys.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
sysctl_binary.c sysctl: add KERN_CONT to deprecated_sysctl_warning() 2016-12-14 16:04:07 -08:00
sysctl.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
task_work.c
taskstats.c
test_kprobes.c
torture.c
tracepoint.c
tsacct.c
ucount.c
uid16.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
up.c
user_namespace.c
user-return-notifier.c
user.c
utsname_sysctl.c
utsname.c
watchdog_hld.c kernel/watchdog: prevent false hardlockup on overloaded system 2017-01-24 16:26:14 -08:00
watchdog.c kernel/watchdog: prevent false hardlockup on overloaded system 2017-01-24 16:26:14 -08:00
workqueue_internal.h
workqueue.c