summaryrefslogtreecommitdiffstats
path: root/kernel
diff options
context:
space:
mode:
authorIngo Molnar <mingo@kernel.org>2013-11-06 06:39:45 +0100
committerIngo Molnar <mingo@kernel.org>2013-11-06 06:39:45 +0100
commit97c53b402fcadb50201c23914f614bf8430d9c20 (patch)
tree3c9b94e866d150c3a2d8ac853e388c38fade8b45 /kernel
parent6a716c90a51338009c3bc1f460829afaed8f922d (diff)
parent5e01dc7b26d9f24f39abace5da98ccbd6a5ceb52 (diff)
downloadlinux-97c53b402fcadb50201c23914f614bf8430d9c20.tar.gz
linux-97c53b402fcadb50201c23914f614bf8430d9c20.tar.bz2
linux-97c53b402fcadb50201c23914f614bf8430d9c20.zip
Merge tag 'v3.12' into core/locking to pick up mutex upates
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/audit.c5
-rw-r--r--kernel/cgroup.c14
-rw-r--r--kernel/context_tracking.c12
-rw-r--r--kernel/events/core.c31
-rw-r--r--kernel/events/ring_buffer.c31
-rw-r--r--kernel/kmod.c4
-rw-r--r--kernel/mutex.c32
-rw-r--r--kernel/params.c6
-rw-r--r--kernel/pid.c5
-rw-r--r--kernel/power/hibernate.c2
-rw-r--r--kernel/power/snapshot.c5
-rw-r--r--kernel/power/user.c8
-rw-r--r--kernel/reboot.c9
-rw-r--r--kernel/sched/fair.c9
-rw-r--r--kernel/softirq.c15
-rw-r--r--kernel/time/clockevents.c65
-rw-r--r--kernel/watchdog.c60
17 files changed, 247 insertions, 66 deletions
diff --git a/kernel/audit.c b/kernel/audit.c
index 91e53d04b6a9..7b0e23a740ce 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -1117,9 +1117,10 @@ struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask,
sleep_time = timeout_start + audit_backlog_wait_time -
jiffies;
- if ((long)sleep_time > 0)
+ if ((long)sleep_time > 0) {
wait_for_auditd(sleep_time);
- continue;
+ continue;
+ }
}
if (audit_rate_check() && printk_ratelimit())
printk(KERN_WARNING
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 2418b6e71a85..8bd9cfdc70d7 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -2039,7 +2039,7 @@ static int cgroup_attach_task(struct cgroup *cgrp, struct task_struct *tsk,
/* @tsk either already exited or can't exit until the end */
if (tsk->flags & PF_EXITING)
- continue;
+ goto next;
/* as per above, nr_threads may decrease, but not increase. */
BUG_ON(i >= group_size);
@@ -2047,7 +2047,7 @@ static int cgroup_attach_task(struct cgroup *cgrp, struct task_struct *tsk,
ent.cgrp = task_cgroup_from_root(tsk, root);
/* nothing to do if this task is already in the cgroup */
if (ent.cgrp == cgrp)
- continue;
+ goto next;
/*
* saying GFP_ATOMIC has no effect here because we did prealloc
* earlier, but it's good form to communicate our expectations.
@@ -2055,7 +2055,7 @@ static int cgroup_attach_task(struct cgroup *cgrp, struct task_struct *tsk,
retval = flex_array_put(group, i, &ent, GFP_ATOMIC);
BUG_ON(retval != 0);
i++;
-
+ next:
if (!threadgroup)
break;
} while_each_thread(leader, tsk);
@@ -3188,11 +3188,9 @@ css_next_descendant_post(struct cgroup_subsys_state *pos,
WARN_ON_ONCE(!rcu_read_lock_held());
- /* if first iteration, visit the leftmost descendant */
- if (!pos) {
- next = css_leftmost_descendant(root);
- return next != root ? next : NULL;
- }
+ /* if first iteration, visit leftmost descendant which may be @root */
+ if (!pos)
+ return css_leftmost_descendant(root);
/* if we visited @root, we're done */
if (pos == root)
diff --git a/kernel/context_tracking.c b/kernel/context_tracking.c
index 247091bf0587..859c8dfd78a1 100644
--- a/kernel/context_tracking.c
+++ b/kernel/context_tracking.c
@@ -51,6 +51,15 @@ void context_tracking_user_enter(void)
unsigned long flags;
/*
+ * Repeat the user_enter() check here because some archs may be calling
+ * this from asm and if no CPU needs context tracking, they shouldn't
+ * go further. Repeat the check here until they support the static key
+ * check.
+ */
+ if (!static_key_false(&context_tracking_enabled))
+ return;
+
+ /*
* Some contexts may involve an exception occuring in an irq,
* leading to that nesting:
* rcu_irq_enter() rcu_user_exit() rcu_user_exit() rcu_irq_exit()
@@ -151,6 +160,9 @@ void context_tracking_user_exit(void)
{
unsigned long flags;
+ if (!static_key_false(&context_tracking_enabled))
+ return;
+
if (in_interrupt())
return;
diff --git a/kernel/events/core.c b/kernel/events/core.c
index dd236b66ca3a..953c14348375 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -3660,6 +3660,26 @@ static void calc_timer_values(struct perf_event *event,
*running = ctx_time - event->tstamp_running;
}
+static void perf_event_init_userpage(struct perf_event *event)
+{
+ struct perf_event_mmap_page *userpg;
+ struct ring_buffer *rb;
+
+ rcu_read_lock();
+ rb = rcu_dereference(event->rb);
+ if (!rb)
+ goto unlock;
+
+ userpg = rb->user_page;
+
+ /* Allow new userspace to detect that bit 0 is deprecated */
+ userpg->cap_bit0_is_deprecated = 1;
+ userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
+
+unlock:
+ rcu_read_unlock();
+}
+
void __weak arch_perf_update_userpage(struct perf_event_mmap_page *userpg, u64 now)
{
}
@@ -4044,6 +4064,7 @@ again:
ring_buffer_attach(event, rb);
rcu_assign_pointer(event->rb, rb);
+ perf_event_init_userpage(event);
perf_event_update_userpage(event);
unlock:
@@ -6746,6 +6767,10 @@ static int perf_copy_attr(struct perf_event_attr __user *uattr,
if (ret)
return -EFAULT;
+ /* disabled for now */
+ if (attr->mmap2)
+ return -EINVAL;
+
if (attr->__reserved_1)
return -EINVAL;
@@ -7213,15 +7238,15 @@ void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
perf_remove_from_context(event);
unaccount_event_cpu(event, src_cpu);
put_ctx(src_ctx);
- list_add(&event->event_entry, &events);
+ list_add(&event->migrate_entry, &events);
}
mutex_unlock(&src_ctx->mutex);
synchronize_rcu();
mutex_lock(&dst_ctx->mutex);
- list_for_each_entry_safe(event, tmp, &events, event_entry) {
- list_del(&event->event_entry);
+ list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
+ list_del(&event->migrate_entry);
if (event->state >= PERF_EVENT_STATE_OFF)
event->state = PERF_EVENT_STATE_INACTIVE;
account_event_cpu(event, dst_cpu);
diff --git a/kernel/events/ring_buffer.c b/kernel/events/ring_buffer.c
index cd55144270b5..9c2ddfbf4525 100644
--- a/kernel/events/ring_buffer.c
+++ b/kernel/events/ring_buffer.c
@@ -87,10 +87,31 @@ again:
goto out;
/*
- * Publish the known good head. Rely on the full barrier implied
- * by atomic_dec_and_test() order the rb->head read and this
- * write.
+ * Since the mmap() consumer (userspace) can run on a different CPU:
+ *
+ * kernel user
+ *
+ * READ ->data_tail READ ->data_head
+ * smp_mb() (A) smp_rmb() (C)
+ * WRITE $data READ $data
+ * smp_wmb() (B) smp_mb() (D)
+ * STORE ->data_head WRITE ->data_tail
+ *
+ * Where A pairs with D, and B pairs with C.
+ *
+ * I don't think A needs to be a full barrier because we won't in fact
+ * write data until we see the store from userspace. So we simply don't
+ * issue the data WRITE until we observe it. Be conservative for now.
+ *
+ * OTOH, D needs to be a full barrier since it separates the data READ
+ * from the tail WRITE.
+ *
+ * For B a WMB is sufficient since it separates two WRITEs, and for C
+ * an RMB is sufficient since it separates two READs.
+ *
+ * See perf_output_begin().
*/
+ smp_wmb();
rb->user_page->data_head = head;
/*
@@ -154,9 +175,11 @@ int perf_output_begin(struct perf_output_handle *handle,
* Userspace could choose to issue a mb() before updating the
* tail pointer. So that all reads will be completed before the
* write is issued.
+ *
+ * See perf_output_put_handle().
*/
tail = ACCESS_ONCE(rb->user_page->data_tail);
- smp_rmb();
+ smp_mb();
offset = head = local_read(&rb->head);
head += size;
if (unlikely(!perf_output_space(rb, tail, offset, head)))
diff --git a/kernel/kmod.c b/kernel/kmod.c
index fb326365b694..b086006c59e7 100644
--- a/kernel/kmod.c
+++ b/kernel/kmod.c
@@ -571,6 +571,10 @@ int call_usermodehelper_exec(struct subprocess_info *sub_info, int wait)
DECLARE_COMPLETION_ONSTACK(done);
int retval = 0;
+ if (!sub_info->path) {
+ call_usermodehelper_freeinfo(sub_info);
+ return -EINVAL;
+ }
helper_lock();
if (!khelper_wq || usermodehelper_disabled) {
retval = -EBUSY;
diff --git a/kernel/mutex.c b/kernel/mutex.c
index 6d647aedffea..d24105b1b794 100644
--- a/kernel/mutex.c
+++ b/kernel/mutex.c
@@ -410,7 +410,7 @@ ww_mutex_set_context_fastpath(struct ww_mutex *lock,
static __always_inline int __sched
__mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
struct lockdep_map *nest_lock, unsigned long ip,
- struct ww_acquire_ctx *ww_ctx)
+ struct ww_acquire_ctx *ww_ctx, const bool use_ww_ctx)
{
struct task_struct *task = current;
struct mutex_waiter waiter;
@@ -450,7 +450,7 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
struct task_struct *owner;
struct mspin_node node;
- if (!__builtin_constant_p(ww_ctx == NULL) && ww_ctx->acquired > 0) {
+ if (use_ww_ctx && ww_ctx->acquired > 0) {
struct ww_mutex *ww;
ww = container_of(lock, struct ww_mutex, base);
@@ -480,7 +480,7 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
if ((atomic_read(&lock->count) == 1) &&
(atomic_cmpxchg(&lock->count, 1, 0) == 1)) {
lock_acquired(&lock->dep_map, ip);
- if (!__builtin_constant_p(ww_ctx == NULL)) {
+ if (use_ww_ctx) {
struct ww_mutex *ww;
ww = container_of(lock, struct ww_mutex, base);
@@ -551,7 +551,7 @@ slowpath:
goto err;
}
- if (!__builtin_constant_p(ww_ctx == NULL) && ww_ctx->acquired > 0) {
+ if (use_ww_ctx && ww_ctx->acquired > 0) {
ret = __mutex_lock_check_stamp(lock, ww_ctx);
if (ret)
goto err;
@@ -575,7 +575,7 @@ skip_wait:
lock_acquired(&lock->dep_map, ip);
mutex_set_owner(lock);
- if (!__builtin_constant_p(ww_ctx == NULL)) {
+ if (use_ww_ctx) {
struct ww_mutex *ww = container_of(lock, struct ww_mutex, base);
struct mutex_waiter *cur;
@@ -615,7 +615,7 @@ mutex_lock_nested(struct mutex *lock, unsigned int subclass)
{
might_sleep();
__mutex_lock_common(lock, TASK_UNINTERRUPTIBLE,
- subclass, NULL, _RET_IP_, NULL);
+ subclass, NULL, _RET_IP_, NULL, 0);
}
EXPORT_SYMBOL_GPL(mutex_lock_nested);
@@ -625,7 +625,7 @@ _mutex_lock_nest_lock(struct mutex *lock, struct lockdep_map *nest)
{
might_sleep();
__mutex_lock_common(lock, TASK_UNINTERRUPTIBLE,
- 0, nest, _RET_IP_, NULL);
+ 0, nest, _RET_IP_, NULL, 0);
}
EXPORT_SYMBOL_GPL(_mutex_lock_nest_lock);
@@ -635,7 +635,7 @@ mutex_lock_killable_nested(struct mutex *lock, unsigned int subclass)
{
might_sleep();
return __mutex_lock_common(lock, TASK_KILLABLE,
- subclass, NULL, _RET_IP_, NULL);
+ subclass, NULL, _RET_IP_, NULL, 0);
}
EXPORT_SYMBOL_GPL(mutex_lock_killable_nested);
@@ -644,7 +644,7 @@ mutex_lock_interruptible_nested(struct mutex *lock, unsigned int subclass)
{
might_sleep();
return __mutex_lock_common(lock, TASK_INTERRUPTIBLE,
- subclass, NULL, _RET_IP_, NULL);
+ subclass, NULL, _RET_IP_, NULL, 0);
}
EXPORT_SYMBOL_GPL(mutex_lock_interruptible_nested);
@@ -682,7 +682,7 @@ __ww_mutex_lock(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
might_sleep();
ret = __mutex_lock_common(&lock->base, TASK_UNINTERRUPTIBLE,
- 0, &ctx->dep_map, _RET_IP_, ctx);
+ 0, &ctx->dep_map, _RET_IP_, ctx, 1);
if (!ret && ctx->acquired > 1)
return ww_mutex_deadlock_injection(lock, ctx);
@@ -697,7 +697,7 @@ __ww_mutex_lock_interruptible(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
might_sleep();
ret = __mutex_lock_common(&lock->base, TASK_INTERRUPTIBLE,
- 0, &ctx->dep_map, _RET_IP_, ctx);
+ 0, &ctx->dep_map, _RET_IP_, ctx, 1);
if (!ret && ctx->acquired > 1)
return ww_mutex_deadlock_injection(lock, ctx);
@@ -809,28 +809,28 @@ __mutex_lock_slowpath(atomic_t *lock_count)
struct mutex *lock = container_of(lock_count, struct mutex, count);
__mutex_lock_common(lock, TASK_UNINTERRUPTIBLE, 0,
- NULL, _RET_IP_, NULL);
+ NULL, _RET_IP_, NULL, 0);
}
static noinline int __sched
__mutex_lock_killable_slowpath(struct mutex *lock)
{
return __mutex_lock_common(lock, TASK_KILLABLE, 0,
- NULL, _RET_IP_, NULL);
+ NULL, _RET_IP_, NULL, 0);
}
static noinline int __sched
__mutex_lock_interruptible_slowpath(struct mutex *lock)
{
return __mutex_lock_common(lock, TASK_INTERRUPTIBLE, 0,
- NULL, _RET_IP_, NULL);
+ NULL, _RET_IP_, NULL, 0);
}
static noinline int __sched
__ww_mutex_lock_slowpath(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
{
return __mutex_lock_common(&lock->base, TASK_UNINTERRUPTIBLE, 0,
- NULL, _RET_IP_, ctx);
+ NULL, _RET_IP_, ctx, 1);
}
static noinline int __sched
@@ -838,7 +838,7 @@ __ww_mutex_lock_interruptible_slowpath(struct ww_mutex *lock,
struct ww_acquire_ctx *ctx)
{
return __mutex_lock_common(&lock->base, TASK_INTERRUPTIBLE, 0,
- NULL, _RET_IP_, ctx);
+ NULL, _RET_IP_, ctx, 1);
}
#endif
diff --git a/kernel/params.c b/kernel/params.c
index 81c4e78c8f4c..c00d5b502aa4 100644
--- a/kernel/params.c
+++ b/kernel/params.c
@@ -254,11 +254,11 @@ int parse_args(const char *doing,
STANDARD_PARAM_DEF(byte, unsigned char, "%hhu", unsigned long, kstrtoul);
-STANDARD_PARAM_DEF(short, short, "%hi", long, kstrtoul);
+STANDARD_PARAM_DEF(short, short, "%hi", long, kstrtol);
STANDARD_PARAM_DEF(ushort, unsigned short, "%hu", unsigned long, kstrtoul);
-STANDARD_PARAM_DEF(int, int, "%i", long, kstrtoul);
+STANDARD_PARAM_DEF(int, int, "%i", long, kstrtol);
STANDARD_PARAM_DEF(uint, unsigned int, "%u", unsigned long, kstrtoul);
-STANDARD_PARAM_DEF(long, long, "%li", long, kstrtoul);
+STANDARD_PARAM_DEF(long, long, "%li", long, kstrtol);
STANDARD_PARAM_DEF(ulong, unsigned long, "%lu", unsigned long, kstrtoul);
int param_set_charp(const char *val, const struct kernel_param *kp)
diff --git a/kernel/pid.c b/kernel/pid.c
index ebe5e80b10f8..9b9a26698144 100644
--- a/kernel/pid.c
+++ b/kernel/pid.c
@@ -273,6 +273,11 @@ void free_pid(struct pid *pid)
*/
wake_up_process(ns->child_reaper);
break;
+ case PIDNS_HASH_ADDING:
+ /* Handle a fork failure of the first process */
+ WARN_ON(ns->child_reaper);
+ ns->nr_hashed = 0;
+ /* fall through */
case 0:
schedule_work(&ns->proc_work);
break;
diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c
index c9c759d5a15c..0121dab83f43 100644
--- a/kernel/power/hibernate.c
+++ b/kernel/power/hibernate.c
@@ -846,7 +846,7 @@ static int software_resume(void)
goto Finish;
}
-late_initcall(software_resume);
+late_initcall_sync(software_resume);
static const char * const hibernation_modes[] = {
diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c
index 358a146fd4da..98c3b34a4cff 100644
--- a/kernel/power/snapshot.c
+++ b/kernel/power/snapshot.c
@@ -743,7 +743,10 @@ int create_basic_memory_bitmaps(void)
struct memory_bitmap *bm1, *bm2;
int error = 0;
- BUG_ON(forbidden_pages_map || free_pages_map);
+ if (forbidden_pages_map && free_pages_map)
+ return 0;
+ else
+ BUG_ON(forbidden_pages_map || free_pages_map);
bm1 = kzalloc(sizeof(struct memory_bitmap), GFP_KERNEL);
if (!bm1)
diff --git a/kernel/power/user.c b/kernel/power/user.c
index 72e8f4fd616d..957f06164ad1 100644
--- a/kernel/power/user.c
+++ b/kernel/power/user.c
@@ -39,6 +39,7 @@ static struct snapshot_data {
char frozen;
char ready;
char platform_support;
+ bool free_bitmaps;
} snapshot_state;
atomic_t snapshot_device_available = ATOMIC_INIT(1);
@@ -82,6 +83,10 @@ static int snapshot_open(struct inode *inode, struct file *filp)
data->swap = -1;
data->mode = O_WRONLY;
error = pm_notifier_call_chain(PM_RESTORE_PREPARE);
+ if (!error) {
+ error = create_basic_memory_bitmaps();
+ data->free_bitmaps = !error;
+ }
if (error)
pm_notifier_call_chain(PM_POST_RESTORE);
}
@@ -111,6 +116,8 @@ static int snapshot_release(struct inode *inode, struct file *filp)
pm_restore_gfp_mask();
free_basic_memory_bitmaps();
thaw_processes();
+ } else if (data->free_bitmaps) {
+ free_basic_memory_bitmaps();
}
pm_notifier_call_chain(data->mode == O_RDONLY ?
PM_POST_HIBERNATION : PM_POST_RESTORE);
@@ -231,6 +238,7 @@ static long snapshot_ioctl(struct file *filp, unsigned int cmd,
break;
pm_restore_gfp_mask();
free_basic_memory_bitmaps();
+ data->free_bitmaps = false;
thaw_processes();
data->frozen = 0;
break;
diff --git a/kernel/reboot.c b/kernel/reboot.c
index 269ed9384cc4..f813b3474646 100644
--- a/kernel/reboot.c
+++ b/kernel/reboot.c
@@ -32,7 +32,14 @@ EXPORT_SYMBOL(cad_pid);
#endif
enum reboot_mode reboot_mode DEFAULT_REBOOT_MODE;
-int reboot_default;
+/*
+ * This variable is used privately to keep track of whether or not
+ * reboot_type is still set to its default value (i.e., reboot= hasn't
+ * been set on the command line). This is needed so that we can
+ * suppress DMI scanning for reboot quirks. Without it, it's
+ * impossible to override a faulty reboot quirk without recompiling.
+ */
+int reboot_default = 1;
int reboot_cpu;
enum reboot_type reboot_type = BOOT_ACPI;
int reboot_force;
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 11cd13667359..7c70201fbc61 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -4242,7 +4242,7 @@ static void update_cfs_rq_h_load(struct cfs_rq *cfs_rq)
}
if (!se) {
- cfs_rq->h_load = rq->avg.load_avg_contrib;
+ cfs_rq->h_load = cfs_rq->runnable_load_avg;
cfs_rq->last_h_load_update = now;
}
@@ -4823,8 +4823,8 @@ void fix_small_imbalance(struct lb_env *env, struct sd_lb_stats *sds)
(busiest->load_per_task * SCHED_POWER_SCALE) /
busiest->group_power;
- if (busiest->avg_load - local->avg_load + scaled_busy_load_per_task >=
- (scaled_busy_load_per_task * imbn)) {
+ if (busiest->avg_load + scaled_busy_load_per_task >=
+ local->avg_load + (scaled_busy_load_per_task * imbn)) {
env->imbalance = busiest->load_per_task;
return;
}
@@ -4896,7 +4896,8 @@ static inline void calculate_imbalance(struct lb_env *env, struct sd_lb_stats *s
* max load less than avg load(as we skip the groups at or below
* its cpu_power, while calculating max_load..)
*/
- if (busiest->avg_load < sds->avg_load) {
+ if (busiest->avg_load <= sds->avg_load ||
+ local->avg_load >= sds->avg_load) {
env->imbalance = 0;
return fix_small_imbalance(env, sds);
}
diff --git a/kernel/softirq.c b/kernel/softirq.c
index 53cc09ceb0b8..d7d498d8cc4f 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -328,10 +328,19 @@ void irq_enter(void)
static inline void invoke_softirq(void)
{
- if (!force_irqthreads)
- __do_softirq();
- else
+ if (!force_irqthreads) {
+ /*
+ * We can safely execute softirq on the current stack if
+ * it is the irq stack, because it should be near empty
+ * at this stage. But we have no way to know if the arch
+ * calls irq_exit() on the irq stack. So call softirq
+ * in its own stack to prevent from any overrun on top
+ * of a potentially deep task stack.
+ */
+ do_softirq();
+ } else {
wakeup_softirqd();
+ }
}
static inline void tick_irq_exit(void)
diff --git a/kernel/time/clockevents.c b/kernel/time/clockevents.c
index 38959c866789..662c5798a685 100644
--- a/kernel/time/clockevents.c
+++ b/kernel/time/clockevents.c
@@ -33,29 +33,64 @@ struct ce_unbind {
int res;
};
-/**
- * clockevents_delta2ns - Convert a latch value (device ticks) to nanoseconds
- * @latch: value to convert
- * @evt: pointer to clock event device descriptor
- *
- * Math helper, returns latch value converted to nanoseconds (bound checked)
- */
-u64 clockevent_delta2ns(unsigned long latch, struct clock_event_device *evt)
+static u64 cev_delta2ns(unsigned long latch, struct clock_event_device *evt,
+ bool ismax)
{
u64 clc = (u64) latch << evt->shift;
+ u64 rnd;
if (unlikely(!evt->mult)) {
evt->mult = 1;
WARN_ON(1);
}
+ rnd = (u64) evt->mult - 1;
+
+ /*
+ * Upper bound sanity check. If the backwards conversion is
+ * not equal latch, we know that the above shift overflowed.
+ */
+ if ((clc >> evt->shift) != (u64)latch)
+ clc = ~0ULL;
+
+ /*
+ * Scaled math oddities:
+ *
+ * For mult <= (1 << shift) we can safely add mult - 1 to
+ * prevent integer rounding loss. So the backwards conversion
+ * from nsec to device ticks will be correct.
+ *
+ * For mult > (1 << shift), i.e. device frequency is > 1GHz we
+ * need to be careful. Adding mult - 1 will result in a value
+ * which when converted back to device ticks can be larger
+ * than latch by up to (mult - 1) >> shift. For the min_delta
+ * calculation we still want to apply this in order to stay
+ * above the minimum device ticks limit. For the upper limit
+ * we would end up with a latch value larger than the upper
+ * limit of the device, so we omit the add to stay below the
+ * device upper boundary.
+ *
+ * Also omit the add if it would overflow the u64 boundary.
+ */
+ if ((~0ULL - clc > rnd) &&
+ (!ismax || evt->mult <= (1U << evt->shift)))
+ clc += rnd;
do_div(clc, evt->mult);
- if (clc < 1000)
- clc = 1000;
- if (clc > KTIME_MAX)
- clc = KTIME_MAX;
- return clc;
+ /* Deltas less than 1usec are pointless noise */
+ return clc > 1000 ? clc : 1000;
+}
+
+/**
+ * clockevents_delta2ns - Convert a latch value (device ticks) to nanoseconds
+ * @latch: value to convert
+ * @evt: pointer to clock event device descriptor
+ *
+ * Math helper, returns latch value converted to nanoseconds (bound checked)
+ */
+u64 clockevent_delta2ns(unsigned long latch, struct clock_event_device *evt)
+{
+ return cev_delta2ns(latch, evt, false);
}
EXPORT_SYMBOL_GPL(clockevent_delta2ns);
@@ -380,8 +415,8 @@ void clockevents_config(struct clock_event_device *dev, u32 freq)
sec = 600;
clockevents_calc_mult_shift(dev, freq, sec);
- dev->min_delta_ns = clockevent_delta2ns(dev->min_delta_ticks, dev);
- dev->max_delta_ns = clockevent_delta2ns(dev->max_delta_ticks, dev);
+ dev->min_delta_ns = cev_delta2ns(dev->min_delta_ticks, dev, false);
+ dev->max_delta_ns = cev_delta2ns(dev->max_delta_ticks, dev, true);
}
/**
diff --git a/kernel/watchdog.c b/kernel/watchdog.c
index 51c4f34d258e..4431610f049a 100644
--- a/kernel/watchdog.c
+++ b/kernel/watchdog.c
@@ -486,7 +486,52 @@ static struct smp_hotplug_thread watchdog_threads = {
.unpark = watchdog_enable,
};
-static int watchdog_enable_all_cpus(void)
+static void restart_watchdog_hrtimer(void *info)
+{
+ struct hrtimer *hrtimer = &__raw_get_cpu_var(watchdog_hrtimer);
+ int ret;
+
+ /*
+ * No need to cancel and restart hrtimer if it is currently executing
+ * because it will reprogram itself with the new period now.
+ * We should never see it unqueued here because we are running per-cpu
+ * with interrupts disabled.
+ */
+ ret = hrtimer_try_to_cancel(hrtimer);
+ if (ret == 1)
+ hrtimer_start(hrtimer, ns_to_ktime(sample_period),
+ HRTIMER_MODE_REL_PINNED);
+}
+
+static void update_timers(int cpu)
+{
+ struct call_single_data data = {.func = restart_watchdog_hrtimer};
+ /*
+ * Make sure that perf event counter will adopt to a new
+ * sampling period. Updating the sampling period directly would
+ * be much nicer but we do not have an API for that now so
+ * let's use a big hammer.
+ * Hrtimer will adopt the new period on the next tick but this
+ * might be late already so we have to restart the timer as well.
+ */
+ watchdog_nmi_disable(cpu);
+ __smp_call_function_single(cpu, &data, 1);
+ watchdog_nmi_enable(cpu);
+}
+
+static void update_timers_all_cpus(void)
+{
+ int cpu;
+
+ get_online_cpus();
+ preempt_disable();
+ for_each_online_cpu(cpu)
+ update_timers(cpu);
+ preempt_enable();
+ put_online_cpus();
+}
+
+static int watchdog_enable_all_cpus(bool sample_period_changed)
{
int err = 0;
@@ -496,6 +541,8 @@ static int watchdog_enable_all_cpus(void)
pr_err("Failed to create watchdog threads, disabled\n");
else
watchdog_running = 1;
+ } else if (sample_period_changed) {
+ update_timers_all_cpus();
}
return err;
@@ -520,13 +567,15 @@ int proc_dowatchdog(struct ctl_table *table, int write,
void __user *buffer, size_t *lenp, loff_t *ppos)
{
int err, old_thresh, old_enabled;
+ static DEFINE_MUTEX(watchdog_proc_mutex);
+ mutex_lock(&watchdog_proc_mutex);
old_thresh = ACCESS_ONCE(watchdog_thresh);
old_enabled = ACCESS_ONCE(watchdog_user_enabled);
err = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
if (err || !write)
- return err;
+ goto out;
set_sample_period();
/*
@@ -535,7 +584,7 @@ int proc_dowatchdog(struct ctl_table *table, int write,
* watchdog_*_all_cpus() function takes care of this.
*/
if (watchdog_user_enabled && watchdog_thresh)
- err = watchdog_enable_all_cpus();
+ err = watchdog_enable_all_cpus(old_thresh != watchdog_thresh);
else
watchdog_disable_all_cpus();
@@ -544,7 +593,8 @@ int proc_dowatchdog(struct ctl_table *table, int write,
watchdog_thresh = old_thresh;
watchdog_user_enabled = old_enabled;
}
-
+out:
+ mutex_unlock(&watchdog_proc_mutex);
return err;
}
#endif /* CONFIG_SYSCTL */
@@ -554,5 +604,5 @@ void __init lockup_detector_init(void)
set_sample_period();
if (watchdog_user_enabled)
- watchdog_enable_all_cpus();
+ watchdog_enable_all_cpus(false);
}