John Stultz 78c7b55b36 timekeeping: Fix __ktime_get_fast_ns() regression ... commit 58bfea9532 upstream. In commit 27727df240 ("Avoid taking lock in NMI path with CONFIG_DEBUG_TIMEKEEPING"), I changed the logic to open-code the timekeeping_get_ns() function, but I forgot to include the unit conversion from cycles to nanoseconds, breaking the function's output, which impacts users like perf. This results in bogus perf timestamps like: swapper 0 [000] 253.427536: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms]) swapper 0 [000] 254.426573: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms]) swapper 0 [000] 254.426687: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms]) swapper 0 [000] 254.426800: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms]) swapper 0 [000] 254.426905: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms]) swapper 0 [000] 254.427022: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms]) swapper 0 [000] 254.427127: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms]) swapper 0 [000] 254.427239: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms]) swapper 0 [000] 254.427346: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms]) swapper 0 [000] 254.427463: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms]) swapper 0 [000] 255.426572: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms]) Instead of more reasonable expected timestamps like: swapper 0 [000] 39.953768: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms]) swapper 0 [000] 40.064839: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms]) swapper 0 [000] 40.175956: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms]) swapper 0 [000] 40.287103: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms]) swapper 0 [000] 40.398217: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms]) swapper 0 [000] 40.509324: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms]) swapper 0 [000] 40.620437: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms]) swapper 0 [000] 40.731546: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms]) swapper 0 [000] 40.842654: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms]) swapper 0 [000] 40.953772: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms]) swapper 0 [000] 41.064881: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms]) Add the proper use of timekeeping_delta_to_ns() to convert the cycle delta to nanoseconds as needed. Thanks to Brendan and Alexei for finding this quickly after the v4.8 release. Unfortunately the problematic commit has landed in some -stable trees so they'll need this fix as well. Many apologies for this mistake. I'll be looking to add a perf-clock sanity test to the kselftest timers tests soon. Fixes: 27727df240 "timekeeping: Avoid taking lock in NMI path with CONFIG_DEBUG_TIMEKEEPING" Reported-by: Brendan Gregg <bgregg@netflix.com> Reported-by: Alexei Starovoitov <alexei.starovoitov@gmail.com> Tested-and-reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Signed-off-by: John Stultz <john.stultz@linaro.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Link: http://lkml.kernel.org/r/1475636148-26539-1-git-send-email-john.stultz@linaro.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2016-10-16 17:36:14 +02:00
..
bpf	bpf, inode: disallow userns mounts	2016-06-24 10:18:17 -07:00
configs	kconfig: tinyconfig: provide whole choice blocks to avoid warnings	2016-09-24 10:07:42 +02:00
debug
events	perf/core: Fix pmu::filter_match for SW-led groups	2016-10-07 15:23:41 +02:00
gcov
irq	genirq/msi: Fix broken debug output	2016-09-24 10:07:46 +02:00
livepatch
locking	locking/qspinlock: Fix spin_unlock_wait() some more	2016-07-27 09:47:29 -07:00
power	PM / hibernate: Fix rtree_next_node() to avoid walking off list ends	2016-09-30 10:18:39 +02:00
printk	printk: fix parsing of "brl=" option	2016-10-07 15:23:43 +02:00
rcu
sched	sched/core: Fix a race between try_to_wake_up() and a woken up task	2016-09-24 10:07:42 +02:00
time	timekeeping: Fix __ktime_get_fast_ns() regression	2016-10-16 17:36:14 +02:00
trace	tracing: Move mutex to protect against resetting of seq data	2016-09-30 10:18:38 +02:00
.gitignore
acct.c
async.c
audit_fsnotify.c
audit_tree.c
audit_watch.c	audit: fix exe_file access in audit_exe_compare	2016-09-24 10:07:36 +02:00
audit.c
audit.h
auditfilter.c
auditsc.c	audit: fix a double fetch in audit_log_single_execve_arg()	2016-08-20 18:09:22 +02:00
backtracetest.c
bounds.c
capability.c	kernel: Add noaudit variant of ns_capable()	2016-09-15 08:27:50 +02:00
cgroup_freezer.c
cgroup_pids.c
cgroup.c	cgroup: set css->id to -1 during init	2016-08-10 11:49:27 +02:00
compat.c
configs.c
context_tracking.c
cpu_pm.c
cpu.c
cpuset.c	cpuset: handle race between CPU hotplug and cpuset_hotplug_work	2016-10-07 15:23:40 +02:00
crash_dump.c
cred.c	cred: Reject inodes with invalid ids in set_create_file_as()	2016-09-15 08:27:49 +02:00
delayacct.c
dma.c
elfcore.c
exec_domain.c
exit.c	wait/ptrace: assume __WALL if the child is traced	2016-06-07 18:14:35 -07:00
extable.c
fork.c	kernel/fork: fix CLONE_CHILD_CLEARTID regression in nscd	2016-10-07 15:23:46 +02:00
freezer.c
futex_compat.c
futex.c	futex: Acknowledge a new waiter in counter before plist	2016-05-04 14:48:43 -07:00
groups.c
hung_task.c
irq_work.c
jump_label.c	locking/static_key: Fix concurrent static_key_slow_inc()	2016-07-27 09:47:29 -07:00
kallsyms.c
kcmp.c
Kconfig.freezer
Kconfig.hz
Kconfig.locks
Kconfig.preempt
kexec_core.c
kexec_file.c	kexec: fix double-free when failing to relocate the purgatory	2016-09-24 10:07:36 +02:00
kexec_internal.h
kexec.c
kmod.c
kprobes.c
ksysfs.c
kthread.c
latencytop.c
Makefile
membarrier.c
memremap.c	devm_memremap: Fix error value when memremap failed	2016-03-03 15:07:08 -08:00
module_signing.c
module-internal.h
module.c	module: Invalidate signatures on force-loaded modules	2016-08-20 18:09:27 +02:00
notifier.c
nsproxy.c
padata.c
panic.c
params.c
pid_namespace.c
pid.c
profile.c
ptrace.c
range.c
reboot.c
relay.c
resource.c	kernel/resource.c: fix muxed resource handling in __request_region()	2016-03-03 15:07:29 -08:00
seccomp.c	seccomp: always propagate NO_NEW_PRIVS on tsync	2016-03-03 15:07:25 -08:00
signal.c
smp.c
smpboot.c
smpboot.h
softirq.c
stacktrace.c
stop_machine.c
sys_ni.c
sys.c
sysctl_binary.c	fs/coredump: prevent fsuid=0 dumps into user-controlled directories	2016-04-12 09:08:58 -07:00
sysctl.c	sysctl: handle error writing UINT_MAX to u32 fields	2016-10-07 15:23:46 +02:00
task_work.c
taskstats.c
test_kprobes.c
torture.c
tracepoint.c
tsacct.c
uid16.c
up.c
user_namespace.c
user-return-notifier.c
user.c
utsname_sysctl.c
utsname.c
watchdog.c	watchdog: don't run proc_watchdog_update if new value is same as old	2016-04-12 09:08:54 -07:00
workqueue_internal.h
workqueue.c	workqueue: fix rebind bound workers warning	2016-05-18 17:06:50 -07:00