linux/kernel
John Stultz d65670a78c clocksource: Avoid selecting mult values that might overflow when adjusted
For some frequencies, the clocks_calc_mult_shift() function will
unfortunately select mult values very close to 0xffffffff.  This
has the potential to overflow when NTP adjusts the clock, adding
to the mult value.

This patch adds a clocksource.maxadj value, which provides
an approximation of an 11% adjustment(NTP limits adjustments to
500ppm and the tick adjustment is limited to 10%), which could
be made to the clocksource.mult value. This is then used to both
check that the current mult value won't overflow/underflow, as
well as warning us if the timekeeping_adjust() code pushes over
that 11% boundary.

v2: Fix max_adjustment calculation, and improve WARN_ONCE
messages.

v3: Don't warn before maxadj has actually been set

CC: Yong Zhang <yong.zhang0@gmail.com>
CC: David Daney <ddaney.cavm@gmail.com>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: Chen Jie <chenj@lemote.com>
CC: zhangfx <zhangfx@lemote.com>
CC: stable@kernel.org
Reported-by: Chen Jie <chenj@lemote.com>
Reported-by: zhangfx <zhangfx@lemote.com>
Tested-by: Yong Zhang <yong.zhang0@gmail.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
2011-11-10 11:27:08 -08:00
..
debug Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/linux-2.6-kgdb 2011-08-01 13:39:40 -10:00
events perf: Remove perf_event_attr::type check 2011-07-21 20:41:55 +02:00
gcov gcov: disable CONSTRUCTORS for UML 2011-07-26 16:49:45 -07:00
irq Merge branch 'imx/dt' into next/dt 2011-07-28 15:25:46 +00:00
power Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2011-07-25 13:56:39 -07:00
time clocksource: Avoid selecting mult values that might overflow when adjusted 2011-11-10 11:27:08 -08:00
trace atomic: use <linux/atomic.h> 2011-07-26 16:49:47 -07:00
.gitignore
acct.c
async.c async: Fixed an include coding style issue 2011-06-14 22:48:46 -04:00
audit_tree.c audit_tree,rcu: Convert call_rcu(__put_tree) to kfree_rcu() 2011-07-20 14:10:11 -07:00
audit_watch.c kill path_lookup() 2011-03-14 09:15:23 -04:00
audit.c atomic: use <linux/atomic.h> 2011-07-26 16:49:47 -07:00
audit.h
auditfilter.c netlink: kill loginuid/sessionid/sid members from struct netlink_skb_parms 2011-03-03 10:55:40 -08:00
auditsc.c atomic: use <linux/atomic.h> 2011-07-26 16:49:47 -07:00
backtracetest.c
bounds.c memcg: remove direct page_cgroup-to-page pointer 2011-03-23 19:46:28 -07:00
capability.c Merge branch 'master' into next 2011-05-19 18:51:57 +10:00
cgroup_freezer.c cgroups: add per-thread subsystem callbacks 2011-05-26 17:12:34 -07:00
cgroup.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/security-testing-2.6 2011-07-27 19:26:38 -07:00
compat.c Merge branch 'v4l_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-2.6 2011-07-30 00:08:53 -07:00
configs.c kernel/configs.c: include MODULE_*() when CONFIG_IKCONFIG_PROC=n 2011-07-25 20:57:15 -07:00
cpu.c Fix common misspellings 2011-03-31 11:26:23 -03:00
cpuset.c atomic: use <linux/atomic.h> 2011-07-26 16:49:47 -07:00
crash_dump.c crash_dump: export is_kdump_kernel to modules, consolidate elfcorehdr_addr, setup_elfcorehdr and saved_max_pfn 2011-03-23 19:47:19 -07:00
cred.c Merge branch 'docs-move' of git://git.kernel.org/pub/scm/linux/kernel/git/rdunlap/linux-docs 2011-05-27 10:25:02 -07:00
delayacct.c KVM: Steal time implementation 2011-07-14 12:59:14 +03:00
dma.c
elfcore.c
exec_domain.c
exit.c ipc: introduce shm_rmid_forced sysctl 2011-07-26 16:49:44 -07:00
extable.c extable, core_kernel_data(): Make sure all archs define _sdata 2011-05-20 08:56:56 +02:00
fork.c kernel/fork.c: fix a few coding style issues 2011-07-26 16:49:44 -07:00
freezer.c Freezer: Use SMP barriers 2011-05-17 23:19:17 +02:00
futex_compat.c userns: user namespaces: convert several capable() calls 2011-03-23 19:47:08 -07:00
futex.c Merge branch 'linus' into core/urgent 2011-08-04 09:09:27 +02:00
groups.c userns: user namespaces: convert several capable() calls 2011-03-23 19:47:08 -07:00
hrtimer.c hrtimers: Fix typo causing erratic timers 2011-05-25 15:31:58 -07:00
hung_task.c watchdog, hung_task_timeout: Add Kconfig configurable default 2011-04-28 09:13:17 +02:00
irq_work.c irq_work: Use per cpu atomics instead of regular atomics 2010-12-18 15:54:48 +01:00
itimer.c
jump_label.c jump_label: Fix jump_label update for modules 2011-06-29 09:59:17 -04:00
kallsyms.c Merge branch 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2011-03-25 17:52:22 -07:00
Kconfig.freezer
Kconfig.hz
Kconfig.locks arch:Kconfig.locks Remove unused config option. 2011-04-10 17:01:05 +02:00
Kconfig.preempt sched: Isolate preempt counting in its own config option 2011-06-10 15:15:40 +02:00
kexec.c treewide: Convert uses of struct resource to resource_size(ptr) 2011-06-10 14:55:36 +02:00
kfifo.c
kmod.c Boot up with usermodehelper disabled 2011-08-03 22:03:29 -10:00
kprobes.c kprobes: Return -ENOENT if probe point doesn't exist 2011-07-15 15:11:47 -04:00
ksysfs.c kernel/ksysfs.c: expose file_caps_enabled in sysfs 2011-04-19 16:45:51 -07:00
kthread.c cpuset: Fix cpuset_cpus_allowed_fallback(), don't update tsk->rt.nr_cpus_allowed 2011-05-28 17:02:57 +02:00
latencytop.c Fix common misspellings 2011-03-31 11:26:23 -03:00
lockdep_internals.h
lockdep_proc.c lockdep: Remove unused 'factor' variable from lockdep_stats_show() 2011-03-23 13:54:47 +01:00
lockdep_states.h
lockdep.c lockdep: Clear whole lockdep_map on initialization 2011-08-04 10:17:56 +02:00
Makefile kernel: prevent unnecessary rebuilding due to config_data.gz 2011-07-20 01:32:32 +02:00
module.c module: add /sys/module/<name>/uevent files 2011-07-24 22:06:04 +09:30
mutex-debug.c mutex: Use p->on_cpu for the adaptive spin 2011-04-14 08:52:33 +02:00
mutex-debug.h mutex: Use p->on_cpu for the adaptive spin 2011-04-14 08:52:33 +02:00
mutex.c lockdep, mutex: provide mutex_lock_nest_lock 2011-05-25 08:39:17 -07:00
mutex.h mutex: Use p->on_cpu for the adaptive spin 2011-04-14 08:52:33 +02:00
notifier.c notifiers: sys: move reboot notifiers into reboot.h 2011-07-25 20:57:14 -07:00
nsproxy.c make sure that nsproxy_cache is initialized early enough 2011-07-20 01:44:07 -04:00
padata.c Fix common misspellings 2011-03-31 11:26:23 -03:00
panic.c panic: panic=-1 for immediate reboot 2011-07-26 16:49:45 -07:00
params.c module: add /sys/module/<name>/uevent files 2011-07-24 22:06:04 +09:30
pid_namespace.c pidns: call pid_ns_prepare_proc() from create_pid_namespace() 2011-03-23 19:46:58 -07:00
pid.c rcu: treewide: Do not use rcu_read_lock_held when calling rcu_dereference_check 2011-07-08 22:21:58 +02:00
pm_qos_params.c plist: Remove the need to supply locks to plist heads 2011-07-08 14:02:53 +02:00
posix-cpu-timers.c posix-cpu-timers: Cure SMP accounting oddities 2011-09-08 15:25:52 +02:00
posix-timers.c posix-timers: RCU conversion 2011-05-24 12:10:51 +02:00
printk.c printk: Fix console_sem vs logbuf_lock unlock race 2011-06-22 11:39:34 +02:00
profile.c kernel/profile.c: remove some duplicate code from profile_hits() 2011-05-26 17:12:37 -07:00
ptrace.c connector: add an event for monitoring process tracers 2011-07-18 21:38:33 +02:00
range.c
rcupdate.c atomic: use <linux/atomic.h> 2011-07-26 16:49:47 -07:00
rcutiny_plugin.h rcu: Converge TINY_RCU expedited and normal boosting 2011-05-05 23:16:58 -07:00
rcutiny.c sanitize <linux/prefetch.h> usage 2011-05-20 12:50:29 -07:00
rcutorture.c atomic: use <linux/atomic.h> 2011-07-26 16:49:47 -07:00
rcutree_plugin.h softirq,rcu: Inform RCU of irq_exit() activity 2011-07-20 10:50:12 -07:00
rcutree_trace.c atomic: use <linux/atomic.h> 2011-07-26 16:49:47 -07:00
rcutree.c rcu: Prevent RCU callbacks from executing before scheduler initialized 2011-07-13 08:17:56 -07:00
rcutree.h rcu: Move RCU_BOOST #ifdefs to header file 2011-06-16 16:12:05 -07:00
relay.c
res_counter.c memcg: res_counter_read_u64(): fix potential races on 32-bit machines 2011-03-23 19:46:22 -07:00
resource.c resources: Add lookup_resource() 2011-07-30 21:21:39 +02:00
rtmutex_common.h rtmutex: Simplify PI algorithm and make highest prio task get lock 2011-01-27 21:13:51 -05:00
rtmutex-debug.c rtmutex: Simplify PI algorithm and make highest prio task get lock 2011-01-27 21:13:51 -05:00
rtmutex-debug.h
rtmutex-tester.c rtmutex: tester: Remove the remaining BKL leftovers 2011-02-22 22:07:22 +01:00
rtmutex.c plist: Remove the need to supply locks to plist heads 2011-07-08 14:02:53 +02:00
rtmutex.h
rwsem.c atomic: use <linux/atomic.h> 2011-07-26 16:49:47 -07:00
sched_autogroup.c Fix common misspellings 2011-03-31 11:26:23 -03:00
sched_autogroup.h sched: Skip autogroup when looking for all rt sched groups 2011-07-01 10:39:08 +02:00
sched_clock.c sched: Add some clock info to sched_debug 2010-11-23 10:29:08 +01:00
sched_cpupri.c
sched_cpupri.h
sched_debug.c sched: Get rid of lock_depth 2011-04-24 13:18:38 +02:00
sched_fair.c sched: Cleanup duplicate local variable in [enqueue|dequeue]_task_fair 2011-07-22 12:47:22 +02:00
sched_features.h Merge branch 'kvm-updates/3.1' of git://git.kernel.org/pub/scm/virt/kvm/kvm 2011-07-24 09:07:03 -07:00
sched_idletask.c sched: Drop the rq argument to sched_class::select_task_rq() 2011-04-14 08:52:36 +02:00
sched_rt.c sched: Skip autogroup when looking for all rt sched groups 2011-07-01 10:39:08 +02:00
sched_stats.h sched: More sched_domain iterations fixes 2011-05-28 17:02:54 +02:00
sched_stoptask.c sched: Drop the rq argument to sched_class::select_task_rq() 2011-04-14 08:52:36 +02:00
sched.c posix-cpu-timers: Cure SMP accounting oddities 2011-09-08 15:25:52 +02:00
seccomp.c
semaphore.c
signal.c signals: sys_ssetmask/sys_rt_sigsuspend should use set_current_blocked() 2011-07-27 12:53:36 -07:00
smp.c generic-ipi: Fix kexec boot crash by initializing call_single_queue before enabling interrupts 2011-06-17 10:17:12 +02:00
softirq.c softirq,rcu: Inform RCU of irq_exit() activity 2011-07-20 10:50:12 -07:00
spinlock.c
srcu.c rcu: demote SRCU_SYNCHRONIZE_DELAY from kernel-parameter status 2011-01-14 04:56:49 -08:00
stacktrace.c stack_trace: Add weak save_stack_trace_regs() 2011-06-14 22:48:52 -04:00
stop_machine.c atomic: use <linux/atomic.h> 2011-07-26 16:49:47 -07:00
sys_ni.c ipc: Add missing sys_ni entries for ipc/compat.c functions 2011-05-20 13:53:02 -07:00
sys.c notifiers: sys: move reboot notifiers into reboot.h 2011-07-25 20:57:14 -07:00
sysctl_binary.c open-style analog of vfs_path_lookup() 2011-03-14 09:15:28 -04:00
sysctl_check.c sysctl_check: drop dead code 2011-03-23 19:46:51 -07:00
sysctl.c sysctl,rcu: Convert call_rcu(free_head) to kfree 2011-07-20 14:10:18 -07:00
taskstats.c taskstats: add_del_listener() should ignore !valid listeners 2011-08-03 14:25:20 -10:00
test_kprobes.c
time.c time: Change jiffies_to_clock_t() argument type to unsigned long 2011-09-21 10:28:51 +02:00
timeconst.pl
timer.c timers: Consider slack value in mod_timer() 2011-06-03 15:02:32 +02:00
tracepoint.c jump label: Introduce static_branch() interface 2011-04-04 12:48:08 -04:00
tsacct.c
uid16.c userns: user namespaces: convert several capable() calls 2011-03-23 19:47:08 -07:00
up.c
user_namespace.c user_ns: improve the user_ns on-the-slab packaging 2011-01-13 08:03:18 -08:00
user-return-notifier.c Fix common misspellings 2011-03-31 11:26:23 -03:00
user.c userns: add a user_namespace as creator/owner of uts_namespace 2011-03-23 19:46:59 -07:00
utsname_sysctl.c
utsname.c ns proc: Add support for the uts namespace 2011-05-10 14:35:35 -07:00
wait.c Fix common misspellings 2011-03-31 11:26:23 -03:00
watchdog.c perf, x86: P4 PMU - Introduce event alias feature 2011-07-14 17:25:04 -04:00
workqueue_sched.h
workqueue.c Merge branch 'for-3.1' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq 2011-07-22 15:07:15 -07:00