Thomas Gleixner 7edaeb6841 kernel/watchdog: Prevent false positives with turbo modes ... The hardlockup detector on x86 uses a performance counter based on unhalted CPU cycles and a periodic hrtimer. The hrtimer period is about 2/5 of the performance counter period, so the hrtimer should fire 2-3 times before the performance counter NMI fires. The NMI code checks whether the hrtimer fired since the last invocation. If not, it assumess a hard lockup. The calculation of those periods is based on the nominal CPU frequency. Turbo modes increase the CPU clock frequency and therefore shorten the period of the perf/NMI watchdog. With extreme Turbo-modes (3x nominal frequency) the perf/NMI period is shorter than the hrtimer period which leads to false positives. A simple fix would be to shorten the hrtimer period, but that comes with the side effect of more frequent hrtimer and softlockup thread wakeups, which is not desired. Implement a low pass filter, which checks the perf/NMI period against kernel time. If the perf/NMI fires before 4/5 of the watchdog period has elapsed then the event is ignored and postponed to the next perf/NMI. That solves the problem and avoids the overhead of shorter hrtimer periods and more frequent softlockup thread wakeups. Fixes: 58687acba5 ("lockup_detector: Combine nmi_watchdog and softlockup detector") Reported-and-tested-by: Kan Liang <Kan.liang@intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: dzickus@redhat.com Cc: prarit@redhat.com Cc: ak@linux.intel.com Cc: babu.moger@oracle.com Cc: peterz@infradead.org Cc: eranian@google.com Cc: acme@redhat.com Cc: stable@vger.kernel.org Cc: atomlin@redhat.com Cc: akpm@linux-foundation.org Cc: torvalds@linux-foundation.org Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1708150931310.1886@nanos		2017-08-18 12:35:02 +02:00
..
842
fonts	lib/fonts/Kconfig: keep non-Sparc fonts listed together	2017-02-27 18:43:46 -08:00
lz4	lib/lz4: remove back-compat wrappers	2017-02-24 17:46:57 -08:00
lzo
mpi
raid6	lib/raid6: Add log-of-2 table for RAID6 HW requiring disk position	2017-05-16 10:01:57 +05:30
reed_solomon
xz
zlib_deflate
zlib_inflate	lib/zlib_inflate/inftrees.c: fix potential buffer overflow	2017-05-08 17:15:12 -07:00
.gitignore
argv_split.c
asn1_decoder.c
assoc_array.c
atomic64_test.c	lib/atomic64_test.c: add a test that atomic64_inc_not_zero() returns an int	2017-07-14 15:05:13 -07:00
atomic64.c
audit.c
bcd.c
bch.c
bitmap.c	bitmap: optimise bitmap_set and bitmap_clear of a single bit	2017-07-10 16:32:34 -07:00
bitrev.c
bsearch.c	lib/bsearch.c: micro-optimize pivot position calculation	2017-07-10 16:32:35 -07:00
btree.c
bug.c	debug: Add _ONCE() logic to report_bug()	2017-03-30 09:37:20 +02:00
build_OID_registry
bust_spinlocks.c
chacha20.c
check_signature.c
checksum.c
clz_ctz.c
clz_tab.c
cmdline.c	lib/cmdline.c: fix get_options() overflow while parsing ranges	2017-06-23 16:15:55 -07:00
compat_audit.c
cordic.c
cpu_rmap.c
cpumask.c	sched/fair, cpumask: Export for_each_cpu_wrap()	2017-05-15 10:15:23 +02:00
crc4.c	lib: Add crc4 module	2017-06-09 11:52:07 +02:00
crc7.c
crc8.c
crc16.c
crc32.c	lib: add module support to crc32 tests	2017-02-24 17:46:57 -08:00
crc32defs.h
crc32test.c	lib: add module support to crc32 tests	2017-02-24 17:46:57 -08:00
crc-ccitt.c
crc-itu-t.c
crc-t10dif.c
ctype.c
debug_info.c
debug_locks.c
debugobjects.c	sched/headers: Prepare for new header dependencies before moving code to <linux/sched/task_stack.h>	2017-03-02 08:42:36 +01:00
dec_and_lock.c
decompress_bunzip2.c
decompress_inflate.c
decompress_unlz4.c	lib/decompress_unlz4: change module to work with new LZ4 module version	2017-02-24 17:46:57 -08:00
decompress_unlzma.c
decompress_unlzo.c
decompress_unxz.c
decompress.c
devres.c	devres: fix devm_ioremap_*() offset parameter kerneldoc description	2017-04-24 13:53:13 -05:00
digsig.c	KEYS: Differentiate uses of rcu_dereference_key() and user_key_payload()	2017-03-02 10:09:00 +11:00
div64.c
dma-debug.c	dmaengine updates for 4.12-rc1	2017-05-09 15:40:28 -07:00
dma-noop.c	dma: Take into account dma_pfn_offset	2017-06-28 06:55:01 -07:00
dma-virt.c	dma-virt: remove dma_supported and mapping_error methods	2017-06-28 06:54:41 -07:00
dump_stack.c	sched/headers: Prepare for new header dependencies before moving code to <linux/sched/debug.h>	2017-03-02 08:42:34 +01:00
dynamic_debug.c
dynamic_queue_limits.c
earlycpio.c
errseq.c	lib: add errseq_t type and infrastructure for handling it	2017-07-06 07:02:24 -04:00
extable.c	lib/extable.c: use bsearch() library function in search_extable()	2017-07-10 16:32:35 -07:00
fault-inject.c	fault-inject: fix wrong should_fail() decision in task context	2017-08-10 15:54:06 -07:00
fdt_empty_tree.c
fdt_ro.c
fdt_rw.c
fdt_strerror.c
fdt_sw.c
fdt_wip.c
fdt.c
find_bit.c	lib/find_bit.c: micro-optimise find_next_*_bit	2017-02-24 17:46:57 -08:00
flex_array.c
flex_proportions.c	percpu_counter: Rename __percpu_counter_add to percpu_counter_add_batch	2017-06-20 15:42:32 -04:00
gcd.c
gen_crc32table.c
genalloc.c
glob.c	lib: add module support to glob tests	2017-02-24 17:46:57 -08:00
globtest.c	lib: add module support to glob tests	2017-02-24 17:46:57 -08:00
hexdump.c
hweight.c
idr.c	idr: Add missing __rcu annotations	2017-02-13 21:44:10 -05:00
inflate.c
int_sqrt.c
interval_tree_test.c	lib/interval_tree_test.c: allow full tree search	2017-07-10 16:32:35 -07:00
interval_tree.c
iomap_copy.c
iomap.c
iommu-common.c
iommu-helper.c
ioremap.c	mm: convert generic code to 5-level paging	2017-03-09 11:48:47 -08:00
iov_iter.c	Merge branch 'uaccess-work.iov_iter' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs	2017-07-07 20:39:20 -07:00
irq_poll.c
irq_regs.c
is_single_threaded.c	sched/headers: Prepare to move 'init_task' and 'init_thread_union' from <linux/sched.h> to <linux/sched/task.h>	2017-03-02 08:42:38 +01:00
jedec_ddr_data.c
kasprintf.c
Kconfig	libnvdimm for 4.13	2017-07-07 09:44:06 -07:00
Kconfig.debug	kernel/watchdog: Prevent false positives with turbo modes	2017-08-18 12:35:02 +02:00
Kconfig.kasan
Kconfig.kgdb	lib: update location of kgdb documentation	2017-05-16 08:44:22 -03:00
Kconfig.kmemcheck
Kconfig.ubsan
kfifo.c
klist.c
kobject_uevent.c	kobject: support passing in variables for synthetic uevents	2017-05-25 18:30:51 +02:00
kobject.c	kobject: Export kobject_get_unless_zero()	2017-03-22 20:11:35 -06:00
kstrtox.c	lib/kstrtox.c: use "unsigned int" more	2017-07-10 16:32:34 -07:00
kstrtox.h
lcm.c
libcrc32c.c	crypto: Work around deallocated stack frame reference gcc bug on sparc.	2017-06-08 17:36:03 +08:00
list_debug.c	bug: switch data corruption check to __must_check	2017-02-24 17:46:56 -08:00
list_sort.c	lib: add module support to linked list sorting tests	2017-05-08 17:15:10 -07:00
llist.c
locking-selftest-hardirq.h
locking-selftest-mutex.h
locking-selftest-rlock-hardirq.h
locking-selftest-rlock-softirq.h
locking-selftest-rlock.h
locking-selftest-rsem.h
locking-selftest-rtmutex.h	locking/selftest: Add RT-mutex support	2017-06-08 10:35:50 +02:00
locking-selftest-softirq.h
locking-selftest-spin-hardirq.h
locking-selftest-spin-softirq.h
locking-selftest-spin.h
locking-selftest-wlock-hardirq.h
locking-selftest-wlock-softirq.h
locking-selftest-wlock.h
locking-selftest-wsem.h
locking-selftest.c	locking/selftest: Add RT-mutex support	2017-06-08 10:35:50 +02:00
lockref.c
lru_cache.c
Makefile	kmod: add test driver to stress test the module loader	2017-07-14 15:05:13 -07:00
memory-notifier-error-inject.c
memweight.c
net_utils.c
netdev-notifier-error-inject.c
nlattr.c	net: manual clean code which call skb_put_[data:zero]	2017-06-20 13:30:15 -04:00
nmi_backtrace.c	printk: Use the main logbuf in NMI when logbuf_lock is available	2017-05-19 14:42:19 +02:00
nodemask.c
notifier-error-inject.c
notifier-error-inject.h
of-reconfig-notifier-error-inject.c
oid_registry.c
once.c
parman.c	lib: Introduce priority array area manager	2017-02-03 16:35:42 -05:00
parser.c
pci_iomap.c
percpu_counter.c	writeback: rework wb_[dec|inc]_stat family of functions	2017-07-12 16:26:05 -07:00
percpu_ida.c	sched/headers: Prepare to remove the <linux/gfp.h> include from <linux/sched.h>	2017-03-02 08:42:34 +01:00
percpu_test.c
percpu-refcount.c	percpu-refcount: support synchronous switch to atomic mode.	2017-03-22 19:18:43 -07:00
plist.c	sched/headers: Prepare for new header dependencies before moving code to <linux/sched/clock.h>	2017-03-02 08:42:27 +01:00
pm-notifier-error-inject.c
prime_numbers.c
radix-tree.c	lockdep: allow to disable reclaim lockup detection	2017-05-03 15:52:09 -07:00
random32.c
ratelimit.c
rational.c
rbtree_test.c
rbtree.c	rbtree: use designated initializers	2017-02-24 17:46:57 -08:00
reciprocal_div.c
refcount.c	locking/refcount: Create unchecked atomic_t implementation	2017-06-28 18:54:46 +02:00
rhashtable.c	Add wait_for_random_bytes() and get_random_*_wait() functions so that	2017-07-15 12:44:02 -07:00
sbitmap.c	sbitmap: add sbitmap_get_shallow() operation	2017-04-14 14:06:52 -06:00
scatterlist.c	scatterlist: add sg_zero_buffer() helper	2017-06-15 14:30:14 +02:00
seq_buf.c
sg_pool.c
sg_split.c
sha1.c
show_mem.c	lib/show_mem.c: teach show_mem to work with the given nodemask	2017-02-22 16:41:30 -08:00
siphash.c
smp_processor_id.c	sched/core: Enable might_sleep() and smp_processor_id() checks early	2017-05-23 10:01:38 +02:00
sort.c	lib: add CONFIG_TEST_SORT to enable self-test of sort()	2017-02-24 17:46:57 -08:00
stackdepot.c
stmp_device.c
string_helpers.c
string.c	include/linux/string.h: add the option of fortified string.h functions	2017-07-12 16:26:03 -07:00
strncpy_from_user.c
strnlen_user.c	kill strlen_user()	2017-05-15 23:40:22 -04:00
swiotlb.c
syscall.c	lib/syscall: Clear return values when no stack	2017-03-24 07:43:35 +01:00
test_bitmap.c	bitmap: optimise bitmap_set and bitmap_clear of a single bit	2017-07-10 16:32:34 -07:00
test_bpf.c	net: introduce __skb_put_[zero, data, u8]	2017-06-20 13:30:14 -04:00
test_firmware.c
test_hash.c
test_hexdump.c
test_kasan.c	kasan: report only the first error by default	2017-03-31 17:13:30 -07:00
test_kmod.c	test_kmod: fix small memory leak on filesystem tests	2017-08-10 15:54:06 -07:00
test_list_sort.c	lib: add module support to linked list sorting tests	2017-05-08 17:15:10 -07:00
test_module.c
test_parman.c	lib: fix spelling mistake: "actualy" -> "actually"	2017-02-26 11:03:38 -05:00
test_printf.c
test_rhashtable.c	lib: test_rhashtable: Fix KASAN warning	2017-07-25 12:35:23 -07:00
test_siphash.c
test_sort.c	Revert "lib/test_sort.c: make it explicitly non-modular"	2017-05-08 17:15:10 -07:00
test_static_key_base.c
test_static_keys.c
test_sysctl.c	test_sysctl: test against int proc_dointvec() array support	2017-07-12 16:26:00 -07:00
test_user_copy.c	lib: remove check for AVR32 arch in test_user_copy	2017-05-01 09:36:30 +02:00
test_uuid.c	uuid: fix incorrect uuid_equal conversion in test_uuid_test	2017-07-21 09:38:30 +02:00
test-kstrtox.c
test-string_helpers.c
textsearch.c
timerqueue.c
ts_bm.c
ts_fsm.c
ts_kmp.c
ubsan.c
ubsan.h
ucs2_string.c
usercopy.c	copy_{from,to}_user(): move kasan checks and might_fault() out-of-line	2017-06-29 22:21:20 -04:00
uuid.c	uuid: hoist uuid_is_null() helper from libnvdimm	2017-06-05 16:59:05 +02:00
vsprintf.c	DeviceTree for 4.13:	2017-07-07 10:37:54 -07:00
win_minmax.c