Gaurav Kohli cb71229f64 timers: Clear timer_base::must_forward_clk with timer_base::lock held ... [ Upstream commit 363e934d88 ] timer_base::must_forward_clock is indicating that the base clock might be stale due to a long idle sleep. The forwarding of the base clock takes place in the timer softirq or when a timer is enqueued to a base which is idle. If the enqueue of timer to an idle base happens from a remote CPU, then the following race can happen: CPU0 CPU1 run_timer_softirq mod_timer base = lock_timer_base(timer); base->must_forward_clk = false if (base->must_forward_clk) forward(base); -> skipped enqueue_timer(base, timer, idx); -> idx is calculated high due to stale base unlock_timer_base(timer); base = lock_timer_base(timer); forward(base); The root cause is that timer_base::must_forward_clk is cleared outside the timer_base::lock held region, so the remote queuing CPU observes it as cleared, but the base clock is still stale. This can cause large granularity values for timers, i.e. the accuracy of the expiry time suffers. Prevent this by clearing the flag with timer_base::lock held, so that the forwarding takes place before the cleared flag is observable by a remote CPU. Signed-off-by: Gaurav Kohli <gkohli@codeaurora.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: john.stultz@linaro.org Cc: sboyd@kernel.org Cc: linux-arm-msm@vger.kernel.org Link: https://lkml.kernel.org/r/1533199863-22748-1-git-send-email-gkohli@codeaurora.org Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2018-09-19 22:43:39 +02:00
..
bpf	bpf: hash map: decrement counter on error	2018-08-24 13:09:12 +02:00
cgroup	cgroup: fix rule checking for threaded mode switching	2018-03-28 18:24:37 +02:00
configs	ANDROID: binder: add hwbinder,vndbinder to BINDER_DEVICES.	2017-08-22 18:43:23 -07:00
debug	kdb: make "mdr" command repeat	2018-05-30 07:52:41 +02:00
events	perf/core: Fix perf_output_read_group()	2018-05-30 07:52:34 +02:00
gcov	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
irq	genirq: Make force irq threading setup more robust	2018-08-09 12:16:38 +02:00
livepatch	livepatch: Validate module/old func name length	2018-09-09 19:55:58 +02:00
locking	locking/rtmutex: Allow specifying a subclass for nested locking	2018-09-05 09:26:29 +02:00
power	PM / sleep: wakeup: Fix build error caused by missing SRCU support	2018-09-09 19:55:58 +02:00
printk	printk/tracing: Do not trace printk_nmi_enter()	2018-09-09 19:55:57 +02:00
rcu	rcu: Call touch_nmi_watchdog() while printing stall warnings	2018-05-30 07:52:39 +02:00
sched	sched/deadline: Fix switching to -deadline	2018-09-15 09:45:35 +02:00
time	timers: Clear timer_base::must_forward_clk with timer_base::lock held	2018-09-19 22:43:39 +02:00
trace	uprobes: Use synchronize_rcu() not synchronize_sched()	2018-09-09 19:55:58 +02:00
.gitignore	…
Kconfig.freezer	…
Kconfig.hz	…
Kconfig.locks	…
Kconfig.preempt	…
Makefile	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
acct.c	kernel/acct.c: fix the acct->needcheck check in check_free_space()	2018-01-10 09:31:17 +01:00
async.c	kernel/async.c: revert "async: simplify lowest_in_progress()"	2018-02-16 20:23:05 +01:00
audit.c	audit: return on memory error to avoid null pointer dereference	2018-05-30 07:52:39 +02:00
audit.h	ipc: mqueue: Replace timespec with timespec64	2017-09-03 20:21:24 -04:00
audit_fsnotify.c	…
audit_tree.c	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
audit_watch.c	…
auditfilter.c	audit: allow not equal op for audit by executable	2018-08-03 07:50:39 +02:00
auditsc.c	audit: fix potential null dereference 'context->module.name'	2018-08-06 16:20:49 +02:00
backtracetest.c	…
bounds.c	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
capability.c	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
compat.c	compat: fix 4-byte infoleak via uninitialized struct field	2018-05-16 10:10:26 +02:00
configs.c	…
context_tracking.c	…
cpu.c	cpu/hotplug: Prevent state corruption on error rollback	2018-09-19 22:43:36 +02:00
cpu_pm.c	…
crash_core.c	kdump: write correct address of mem_section into vmcoreinfo	2018-01-17 09:45:27 +01:00
crash_dump.c	…
cred.c	…
delayacct.c	delayacct: Use raw_spinlocks	2018-08-03 07:50:38 +02:00
dma.c	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
elfcore.c	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
exec_domain.c	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
exit.c	kernel/exit.c: export abort() to modules	2018-02-13 10:19:49 +01:00
extable.c	extable: Enable RCU if it is not watching in kernel_text_address()	2017-09-23 16:50:20 -04:00
fork.c	fork: don't copy inconsistent signal handler state to child	2018-09-15 09:45:27 +02:00
freezer.c	…
futex.c	futex: Fix OWNER_DEAD fixup	2018-02-03 17:38:47 +01:00
futex_compat.c	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
groups.c	kernel: make groups_sort calling a responsibility group_info allocators	2017-12-20 10:10:18 +01:00
hung_task.c	kernel/hung_task.c: show all hung tasks before panic	2018-08-03 07:50:23 +02:00
irq_work.c	…
jump_label.c	jump_label: Invoke jump_label_test() via early_initcall()	2017-12-14 09:53:13 +01:00
kallsyms.c	…
kcmp.c	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
kcov.c	kcov: ensure irq code sees a valid area	2018-08-03 07:50:22 +02:00
kexec.c	…
kexec_core.c	…
kexec_file.c	…
kexec_internal.h	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
kmod.c	kmod: move #ifdef CONFIG_MODULES wrapper to Makefile	2017-09-08 18:26:51 -07:00
kprobes.c	kprobes: Make list and blacklist root user read only	2018-09-05 09:26:41 +02:00
ksysfs.c	…
kthread.c	kthread, tracing: Don't expose half-written comm when creating kthreads	2018-08-03 07:50:21 +02:00
latencytop.c	…
memremap.c	mm: Fix devm_memremap_pages() collision handling	2018-09-15 09:45:35 +02:00
module-internal.h	…
module.c	init: fix false positives in W+X checking	2018-06-21 04:02:57 +09:00
module_signing.c	…
notifier.c	…
nsproxy.c	…
padata.c	…
panic.c	…
params.c	kernel/params.c: improve STANDARD_PARAM_DEF readability	2017-10-03 17:54:26 -07:00
pid.c	pids: make task_tgid_nr_ns() safe	2017-08-21 12:47:31 -07:00
pid_namespace.c	…
profile.c	…
ptrace.c	…
range.c	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
reboot.c	…
relay.c	kernel/relay.c: limit kmalloc size to KMALLOC_MAX_SIZE	2018-05-30 07:52:00 +02:00
resource.c	resource: fix integer overflow at reallocation	2018-04-24 09:36:22 +02:00
seccomp.c	seccomp: Move speculation migitation control to arch code	2018-05-22 18:54:04 +02:00
signal.c	sched/core: Introduce set_special_state()	2018-06-21 04:02:54 +09:00
smp.c	cpu/hotplug: Fix SMT supported evaluation	2018-08-15 18:13:00 +02:00
smpboot.c	watchdog/core, powerpc: Lock cpus across reconfiguration	2017-10-04 10:53:54 +02:00
smpboot.h	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
softirq.c	Mark HI and TASKLET softirq synchronous	2018-08-15 18:12:47 +02:00
stacktrace.c	…
stop_machine.c	stop_machine: Atomically queue and wake stopper threads	2018-09-05 09:26:36 +02:00
sys.c	sys: don't hold uts_sem while accessing userspace memory	2018-09-09 19:56:00 +02:00
sys_ni.c	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
sysctl.c	kmemcheck: rip it out	2018-02-22 15:42:24 +01:00
sysctl_binary.c	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
task_work.c	locking/barriers: Convert users of lockless_dereference() to READ_ONCE()	2017-12-25 14:26:21 +01:00
taskstats.c	…
test_kprobes.c	…
torture.c	…
tracepoint.c	tracepoint: Do not warn on ENOMEM	2018-05-09 09:51:50 +02:00
tsacct.c	…
ucount.c	…
uid16.c	kernel: make groups_sort calling a responsibility group_info allocators	2017-12-20 10:10:18 +01:00
umh.c	kmod: split out umh code into its own file	2017-09-08 18:26:50 -07:00
up.c	smp: Avoid using two cache lines for struct call_single_data	2017-08-29 15:14:38 +02:00
user-return-notifier.c	…
user.c	…
user_namespace.c	userns: move user access out of the mutex	2018-09-09 19:56:00 +02:00
utsname.c	…
utsname_sysctl.c	sys: don't hold uts_sem while accessing userspace memory	2018-09-09 19:56:00 +02:00
watchdog.c	watchdog: Mark watchdog touch functions as notrace	2018-09-05 09:26:42 +02:00
watchdog_hld.c	watchdog: Mark watchdog touch functions as notrace	2018-09-05 09:26:42 +02:00
workqueue.c	watchdog: Mark watchdog touch functions as notrace	2018-09-05 09:26:42 +02:00
workqueue_internal.h	Merge branch 'for-4.14-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq	2017-11-06 12:26:49 -08:00