29 files changed, 421 insertions, 166 deletions

diff --git a/kernel/Makefile b/kernel/Makefile
index 780c8dcf4516..2093a691f1c2 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -96,6 +96,7 @@ obj-$(CONFIG_HAVE_GENERIC_DMA_COHERENT) += dma-coherent.o
 obj-$(CONFIG_FUNCTION_TRACER) += trace/
 obj-$(CONFIG_TRACING) += trace/
 obj-$(CONFIG_X86_DS) += trace/
+obj-$(CONFIG_RING_BUFFER) += trace/
 obj-$(CONFIG_SMP) += sched_cpupri.o
 obj-$(CONFIG_SLOW_WORK) += slow-work.o
 obj-$(CONFIG_PERF_COUNTERS) += perf_counter.o
diff --git a/kernel/acct.c b/kernel/acct.c
index 7afa31564162..9f3391090b3e 100644
--- a/kernel/acct.c
+++ b/kernel/acct.c
@@ -215,6 +215,7 @@ static void acct_file_reopen(struct bsd_acct_struct *acct, struct file *file,
 static int acct_on(char *name)
 {
         struct file *file;
+        struct vfsmount *mnt;
         int error;
         struct pid_namespace *ns;
         struct bsd_acct_struct *acct = NULL;
@@ -256,11 +257,12 @@ static int acct_on(char *name)
                 acct = NULL;
         }
 
-        mnt_pin(file->f_path.mnt);
+        mnt = file->f_path.mnt;
+        mnt_pin(mnt);
         acct_file_reopen(ns->bacct, file, ns);
         spin_unlock(&acct_lock);
 
-        mntput(file->f_path.mnt); /* it's pinned, now give up active reference */
+        mntput(mnt); /* it's pinned, now give up active reference */
         kfree(acct);
 
         return 0;
diff --git a/kernel/exit.c b/kernel/exit.c
index 628d41f0dd54..869dc221733e 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -12,7 +12,6 @@
 #include <linux/completion.h>
 #include <linux/personality.h>
 #include <linux/tty.h>
-#include <linux/mnt_namespace.h>
 #include <linux/iocontext.h>
 #include <linux/key.h>
 #include <linux/security.h>
diff --git a/kernel/fork.c b/kernel/fork.c
index 467746b3f0aa..bd2959228871 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -17,7 +17,6 @@
 #include <linux/module.h>
 #include <linux/vmalloc.h>
 #include <linux/completion.h>
-#include <linux/mnt_namespace.h>
 #include <linux/personality.h>
 #include <linux/mempolicy.h>
 #include <linux/sem.h>
diff --git a/kernel/futex.c b/kernel/futex.c
index 1c337112335c..794c862125fe 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -299,7 +299,7 @@ void put_futex_key(int fshared, union futex_key *key)
 static int fault_in_user_writeable(u32 __user *uaddr)
 {
         int ret = get_user_pages(current, current->mm, (unsigned long)uaddr,
-                                 sizeof(*uaddr), 1, 0, NULL, NULL);
+                                 1, 1, 0, NULL, NULL);
         return ret < 0 ? ret : 0;
 }
 
diff --git a/kernel/kmod.c b/kernel/kmod.c
index 7e95bedb2bfc..385c31a1bdbf 100644
--- a/kernel/kmod.c
+++ b/kernel/kmod.c
@@ -24,7 +24,6 @@
 #include <linux/unistd.h>
 #include <linux/kmod.h>
 #include <linux/slab.h>
-#include <linux/mnt_namespace.h>
 #include <linux/completion.h>
 #include <linux/file.h>
 #include <linux/fdtable.h>
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index c0fa54b276d9..16b5739c516a 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -237,13 +237,9 @@ static int __kprobes collect_garbage_slots(void)
 {
         struct kprobe_insn_page *kip;
         struct hlist_node *pos, *next;
-        int safety;
 
         /* Ensure no-one is preepmted on the garbages */
-        mutex_unlock(&kprobe_insn_mutex);
-        safety = check_safety();
-        mutex_lock(&kprobe_insn_mutex);
-        if (safety != 0)
+        if (check_safety())
                 return -EAGAIN;
 
         hlist_for_each_entry_safe(kip, pos, next, &kprobe_insn_pages, hlist) {
diff --git a/kernel/module.c b/kernel/module.c
index 38928fcaff2b..0a049837008e 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -2451,9 +2451,9 @@ SYSCALL_DEFINE3(init_module, void __user *, umod,
                 return ret;
         }
         if (ret > 0) {
-                printk(KERN_WARNING "%s: '%s'->init suspiciously returned %d, "
-                                    "it should follow 0/-E convention\n"
-                       KERN_WARNING "%s: loading module anyway...\n",
+                printk(KERN_WARNING
+"%s: '%s'->init suspiciously returned %d, it should follow 0/-E convention\n"
+"%s: loading module anyway...\n",
                        __func__, mod->name, ret,
                        __func__);
                 dump_stack();
diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c
index 1a933a221ea4..a641eb753b8c 100644
--- a/kernel/perf_counter.c
+++ b/kernel/perf_counter.c
@@ -236,6 +236,8 @@ list_add_counter(struct perf_counter *counter, struct perf_counter_context *ctx)
 
         list_add_rcu(&counter->event_entry, &ctx->event_list);
         ctx->nr_counters++;
+        if (counter->attr.inherit_stat)
+                ctx->nr_stat++;
 }
 
 /*
@@ -250,6 +252,8 @@ list_del_counter(struct perf_counter *counter, struct perf_counter_context *ctx)
         if (list_empty(&counter->list_entry))
                 return;
         ctx->nr_counters--;
+        if (counter->attr.inherit_stat)
+                ctx->nr_stat--;
 
         list_del_init(&counter->list_entry);
         list_del_rcu(&counter->event_entry);
@@ -1006,6 +1010,81 @@ static int context_equiv(struct perf_counter_context *ctx1,
                 && !ctx1->pin_count && !ctx2->pin_count;
 }
 
+static void __perf_counter_read(void *counter);
+
+static void __perf_counter_sync_stat(struct perf_counter *counter,
+                                     struct perf_counter *next_counter)
+{
+        u64 value;
+
+        if (!counter->attr.inherit_stat)
+                return;
+
+        /*
+         * Update the counter value, we cannot use perf_counter_read()
+         * because we're in the middle of a context switch and have IRQs
+         * disabled, which upsets smp_call_function_single(), however
+         * we know the counter must be on the current CPU, therefore we
+         * don't need to use it.
+         */
+        switch (counter->state) {
+        case PERF_COUNTER_STATE_ACTIVE:
+                __perf_counter_read(counter);
+                break;
+
+        case PERF_COUNTER_STATE_INACTIVE:
+                update_counter_times(counter);
+                break;
+
+        default:
+                break;
+        }
+
+        /*
+         * In order to keep per-task stats reliable we need to flip the counter
+         * values when we flip the contexts.
+         */
+        value = atomic64_read(&next_counter->count);
+        value = atomic64_xchg(&counter->count, value);
+        atomic64_set(&next_counter->count, value);
+
+        swap(counter->total_time_enabled, next_counter->total_time_enabled);
+        swap(counter->total_time_running, next_counter->total_time_running);
+
+        /*
+         * Since we swizzled the values, update the user visible data too.
+         */
+        perf_counter_update_userpage(counter);
+        perf_counter_update_userpage(next_counter);
+}
+
+#define list_next_entry(pos, member) \
+        list_entry(pos->member.next, typeof(*pos), member)
+
+static void perf_counter_sync_stat(struct perf_counter_context *ctx,
+                                   struct perf_counter_context *next_ctx)
+{
+        struct perf_counter *counter, *next_counter;
+
+        if (!ctx->nr_stat)
+                return;
+
+        counter = list_first_entry(&ctx->event_list,
+                                   struct perf_counter, event_entry);
+
+        next_counter = list_first_entry(&next_ctx->event_list,
+                                        struct perf_counter, event_entry);
+
+        while (&counter->event_entry != &ctx->event_list &&
+               &next_counter->event_entry != &next_ctx->event_list) {
+
+                __perf_counter_sync_stat(counter, next_counter);
+
+                counter = list_next_entry(counter, event_entry);
+                next_counter = list_next_entry(counter, event_entry);
+        }
+}
+
 /*
  * Called from scheduler to remove the counters of the current task,
  * with interrupts disabled.
@@ -1061,6 +1140,8 @@ void perf_counter_task_sched_out(struct task_struct *task,
                         ctx->task = next;
                         next_ctx->task = task;
                         do_switch = 0;
+
+                        perf_counter_sync_stat(ctx, next_ctx);
                 }
                 spin_unlock(&next_ctx->lock);
                 spin_unlock(&ctx->lock);
@@ -1348,9 +1429,56 @@ void perf_counter_task_tick(struct task_struct *curr, int cpu)
 }
 
 /*
+ * Enable all of a task's counters that have been marked enable-on-exec.
+ * This expects task == current.
+ */
+static void perf_counter_enable_on_exec(struct task_struct *task)
+{
+        struct perf_counter_context *ctx;
+        struct perf_counter *counter;
+        unsigned long flags;
+        int enabled = 0;
+
+        local_irq_save(flags);
+        ctx = task->perf_counter_ctxp;
+        if (!ctx || !ctx->nr_counters)
+                goto out;
+
+        __perf_counter_task_sched_out(ctx);
+
+        spin_lock(&ctx->lock);
+
+        list_for_each_entry(counter, &ctx->counter_list, list_entry) {
+                if (!counter->attr.enable_on_exec)
+                        continue;
+                counter->attr.enable_on_exec = 0;
+                if (counter->state >= PERF_COUNTER_STATE_INACTIVE)
+                        continue;
+                counter->state = PERF_COUNTER_STATE_INACTIVE;
+                counter->tstamp_enabled =
+                        ctx->time - counter->total_time_enabled;
+                enabled = 1;
+        }
+
+        /*
+         * Unclone this context if we enabled any counter.
+         */
+        if (enabled && ctx->parent_ctx) {
+                put_ctx(ctx->parent_ctx);
+                ctx->parent_ctx = NULL;
+        }
+
+        spin_unlock(&ctx->lock);
+
+        perf_counter_task_sched_in(task, smp_processor_id());
+ out:
+        local_irq_restore(flags);
+}
+
+/*
  * Cross CPU call to read the hardware counter
  */
-static void __read(void *info)
+static void __perf_counter_read(void *info)
 {
         struct perf_counter *counter = info;
         struct perf_counter_context *ctx = counter->ctx;
@@ -1372,7 +1500,7 @@ static u64 perf_counter_read(struct perf_counter *counter)
          */
         if (counter->state == PERF_COUNTER_STATE_ACTIVE) {
                 smp_call_function_single(counter->oncpu,
-                                         __read, counter, 1);
+                                         __perf_counter_read, counter, 1);
         } else if (counter->state == PERF_COUNTER_STATE_INACTIVE) {
                 update_counter_times(counter);
         }
@@ -1508,11 +1636,13 @@ static void free_counter(struct perf_counter *counter)
 {
         perf_pending_sync(counter);
 
-        atomic_dec(&nr_counters);
-        if (counter->attr.mmap)
-                atomic_dec(&nr_mmap_counters);
-        if (counter->attr.comm)
-                atomic_dec(&nr_comm_counters);
+        if (!counter->parent) {
+                atomic_dec(&nr_counters);
+                if (counter->attr.mmap)
+                        atomic_dec(&nr_mmap_counters);
+                if (counter->attr.comm)
+                        atomic_dec(&nr_comm_counters);
+        }
 
         if (counter->destroy)
                 counter->destroy(counter);
@@ -1751,6 +1881,14 @@ int perf_counter_task_disable(void)
         return 0;
 }
 
+static int perf_counter_index(struct perf_counter *counter)
+{
+        if (counter->state != PERF_COUNTER_STATE_ACTIVE)
+                return 0;
+
+        return counter->hw.idx + 1 - PERF_COUNTER_INDEX_OFFSET;
+}
+
 /*
  * Callers need to ensure there can be no nesting of this function, otherwise
  * the seqlock logic goes bad. We can not serialize this because the arch
@@ -1775,11 +1913,17 @@ void perf_counter_update_userpage(struct perf_counter *counter)
         preempt_disable();
         ++userpg->lock;
         barrier();
-        userpg->index = counter->hw.idx;
+        userpg->index = perf_counter_index(counter);
         userpg->offset = atomic64_read(&counter->count);
         if (counter->state == PERF_COUNTER_STATE_ACTIVE)
                 userpg->offset -= atomic64_read(&counter->hw.prev_count);
 
+        userpg->time_enabled = counter->total_time_enabled +
+                        atomic64_read(&counter->child_total_time_enabled);
+
+        userpg->time_running = counter->total_time_running +
+                        atomic64_read(&counter->child_total_time_running);
+
         barrier();
         ++userpg->lock;
         preempt_enable();
@@ -1876,7 +2020,7 @@ fail:
 
 static void perf_mmap_free_page(unsigned long addr)
 {
-        struct page *page = virt_to_page(addr);
+        struct page *page = virt_to_page((void *)addr);
 
         page->mapping = NULL;
         __free_page(page);
@@ -2483,15 +2627,14 @@ static void perf_counter_output(struct perf_counter *counter, int nmi,
                 u32 cpu, reserved;
         } cpu_entry;
 
-        header.type = 0;
+        header.type = PERF_EVENT_SAMPLE;
         header.size = sizeof(header);
 
-        header.misc = PERF_EVENT_MISC_OVERFLOW;
+        header.misc = 0;
         header.misc |= perf_misc_flags(data->regs);
 
         if (sample_type & PERF_SAMPLE_IP) {
                 ip = perf_instruction_pointer(data->regs);
-                header.type |= PERF_SAMPLE_IP;
                 header.size += sizeof(ip);
         }
 
@@ -2500,7 +2643,6 @@ static void perf_counter_output(struct perf_counter *counter, int nmi,
                 tid_entry.pid = perf_counter_pid(counter, current);
                 tid_entry.tid = perf_counter_tid(counter, current);
 
-                header.type |= PERF_SAMPLE_TID;
                 header.size += sizeof(tid_entry);
         }
 
@@ -2510,34 +2652,25 @@ static void perf_counter_output(struct perf_counter *counter, int nmi,
                  */
                 time = sched_clock();
 
-                header.type |= PERF_SAMPLE_TIME;
                 header.size += sizeof(u64);
         }
 
-        if (sample_type & PERF_SAMPLE_ADDR) {
-                header.type |= PERF_SAMPLE_ADDR;
+        if (sample_type & PERF_SAMPLE_ADDR)
                 header.size += sizeof(u64);
-        }
 
-        if (sample_type & PERF_SAMPLE_ID) {
-                header.type |= PERF_SAMPLE_ID;
+        if (sample_type & PERF_SAMPLE_ID)
                 header.size += sizeof(u64);
-        }
 
         if (sample_type & PERF_SAMPLE_CPU) {
-                header.type |= PERF_SAMPLE_CPU;
                 header.size += sizeof(cpu_entry);
 
                 cpu_entry.cpu = raw_smp_processor_id();
         }
 
-        if (sample_type & PERF_SAMPLE_PERIOD) {
-                header.type |= PERF_SAMPLE_PERIOD;
+        if (sample_type & PERF_SAMPLE_PERIOD)
                 header.size += sizeof(u64);
-        }
 
         if (sample_type & PERF_SAMPLE_GROUP) {
-                header.type |= PERF_SAMPLE_GROUP;
                 header.size += sizeof(u64) +
                         counter->nr_siblings * sizeof(group_entry);
         }
@@ -2547,10 +2680,9 @@ static void perf_counter_output(struct perf_counter *counter, int nmi,
 
                 if (callchain) {
                         callchain_size = (1 + callchain->nr) * sizeof(u64);
-
-                        header.type |= PERF_SAMPLE_CALLCHAIN;
                         header.size += callchain_size;
-                }
+                } else
+                        header.size += sizeof(u64);
         }
 
         ret = perf_output_begin(&handle, counter, header.size, nmi, 1);
@@ -2601,13 +2733,79 @@ static void perf_counter_output(struct perf_counter *counter, int nmi,
                 }
         }
 
-        if (callchain)
-                perf_output_copy(&handle, callchain, callchain_size);
+        if (sample_type & PERF_SAMPLE_CALLCHAIN) {
+                if (callchain)
+                        perf_output_copy(&handle, callchain, callchain_size);
+                else {
+                        u64 nr = 0;
+                        perf_output_put(&handle, nr);
+                }
+        }
 
         perf_output_end(&handle);
 }
 
 /*
+ * read event
+ */
+
+struct perf_read_event {
+        struct perf_event_header        header;
+
+        u32                             pid;
+        u32                             tid;
+        u64                             value;
+        u64                             format[3];
+};
+
+static void
+perf_counter_read_event(struct perf_counter *counter,
+                        struct task_struct *task)
+{
+        struct perf_output_handle handle;
+        struct perf_read_event event = {
+                .header = {
+                        .type = PERF_EVENT_READ,
+                        .misc = 0,
+                        .size = sizeof(event) - sizeof(event.format),
+                },
+                .pid = perf_counter_pid(counter, task),
+                .tid = perf_counter_tid(counter, task),
+                .value = atomic64_read(&counter->count),
+        };
+        int ret, i = 0;
+
+        if (counter->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
+                event.header.size += sizeof(u64);
+                event.format[i++] = counter->total_time_enabled;
+        }
+
+        if (counter->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
+                event.header.size += sizeof(u64);
+                event.format[i++] = counter->total_time_running;
+        }
+
+        if (counter->attr.read_format & PERF_FORMAT_ID) {
+                u64 id;
+
+                event.header.size += sizeof(u64);
+                if (counter->parent)
+                        id = counter->parent->id;
+                else
+                        id = counter->id;
+
+                event.format[i++] = id;
+        }
+
+        ret = perf_output_begin(&handle, counter, event.header.size, 0, 0);
+        if (ret)
+                return;
+
+        perf_output_copy(&handle, &event, event.header.size);
+        perf_output_end(&handle);
+}
+
+/*
  * fork tracking
  */
 
@@ -2798,6 +2996,9 @@ void perf_counter_comm(struct task_struct *task)
 {
         struct perf_comm_event comm_event;
 
+        if (task->perf_counter_ctxp)
+                perf_counter_enable_on_exec(task);
+
         if (!atomic_read(&nr_comm_counters))
                 return;
 
@@ -3317,8 +3518,8 @@ out:
         put_cpu_var(perf_cpu_context);
 }
 
-void
-perf_swcounter_event(u32 event, u64 nr, int nmi, struct pt_regs *regs, u64 addr)
+void __perf_swcounter_event(u32 event, u64 nr, int nmi,
+                            struct pt_regs *regs, u64 addr)
 {
         struct perf_sample_data data = {
                 .regs = regs,
@@ -3509,9 +3710,21 @@ static const struct pmu *tp_perf_counter_init(struct perf_counter *counter)
 }
 #endif
 
+atomic_t perf_swcounter_enabled[PERF_COUNT_SW_MAX];
+
+static void sw_perf_counter_destroy(struct perf_counter *counter)
+{
+        u64 event = counter->attr.config;
+
+        WARN_ON(counter->parent);
+
+        atomic_dec(&perf_swcounter_enabled[event]);
+}
+
 static const struct pmu *sw_perf_counter_init(struct perf_counter *counter)
 {
         const struct pmu *pmu = NULL;
+        u64 event = counter->attr.config;
 
         /*
          * Software counters (currently) can't in general distinguish
@@ -3520,7 +3733,7 @@ static const struct pmu *sw_perf_counter_init(struct perf_counter *counter)
          * to be kernel events, and page faults are never hypervisor
          * events.
          */
-        switch (counter->attr.config) {
+        switch (event) {
         case PERF_COUNT_SW_CPU_CLOCK:
                 pmu = &perf_ops_cpu_clock;
 
@@ -3541,6 +3754,10 @@ static const struct pmu *sw_perf_counter_init(struct perf_counter *counter)
         case PERF_COUNT_SW_PAGE_FAULTS_MAJ:
         case PERF_COUNT_SW_CONTEXT_SWITCHES:
         case PERF_COUNT_SW_CPU_MIGRATIONS:
+                if (!counter->parent) {
+                        atomic_inc(&perf_swcounter_enabled[event]);
+                        counter->destroy = sw_perf_counter_destroy;
+                }
                 pmu = &perf_ops_generic;
                 break;
         }
@@ -3556,6 +3773,7 @@ perf_counter_alloc(struct perf_counter_attr *attr,
                    int cpu,
                    struct perf_counter_context *ctx,
                    struct perf_counter *group_leader,
+                   struct perf_counter *parent_counter,
                    gfp_t gfpflags)
 {
         const struct pmu *pmu;
@@ -3591,6 +3809,8 @@ perf_counter_alloc(struct perf_counter_attr *attr,
         counter->ctx            = ctx;
         counter->oncpu          = -1;
 
+        counter->parent         = parent_counter;
+
         counter->ns             = get_pid_ns(current->nsproxy->pid_ns);
         counter->id             = atomic64_inc_return(&perf_counter_id);
 
@@ -3648,11 +3868,13 @@ done:
 
         counter->pmu = pmu;
 
-        atomic_inc(&nr_counters);
-        if (counter->attr.mmap)
-                atomic_inc(&nr_mmap_counters);
-        if (counter->attr.comm)
-                atomic_inc(&nr_comm_counters);
+        if (!counter->parent) {
+                atomic_inc(&nr_counters);
+                if (counter->attr.mmap)
+                        atomic_inc(&nr_mmap_counters);
+                if (counter->attr.comm)
+                        atomic_inc(&nr_comm_counters);
+        }
 
         return counter;
 }
@@ -3815,7 +4037,7 @@ SYSCALL_DEFINE5(perf_counter_open,
         }
 
         counter = perf_counter_alloc(&attr, cpu, ctx, group_leader,
-                                     GFP_KERNEL);
+                                     NULL, GFP_KERNEL);
         ret = PTR_ERR(counter);
         if (IS_ERR(counter))
                 goto err_put_context;
@@ -3881,7 +4103,8 @@ inherit_counter(struct perf_counter *parent_counter,
 
         child_counter = perf_counter_alloc(&parent_counter->attr,
                                            parent_counter->cpu, child_ctx,
-                                           group_leader, GFP_KERNEL);
+                                           group_leader, parent_counter,
+                                           GFP_KERNEL);
         if (IS_ERR(child_counter))
                 return child_counter;
         get_ctx(child_ctx);
@@ -3904,12 +4127,6 @@ inherit_counter(struct perf_counter *parent_counter,
          */
         add_counter_to_ctx(child_counter, child_ctx);
 
-        child_counter->parent = parent_counter;
-        /*
-         * inherit into child's child as well:
-         */
-        child_counter->attr.inherit = 1;
-
         /*
          * Get a reference to the parent filp - we will fput it
          * when the child counter exits. This is safe to do because
@@ -3953,10 +4170,14 @@ static int inherit_group(struct perf_counter *parent_counter,
 }
 
 static void sync_child_counter(struct perf_counter *child_counter,
-                               struct perf_counter *parent_counter)
+                               struct task_struct *child)
 {
+        struct perf_counter *parent_counter = child_counter->parent;
         u64 child_val;
 
+        if (child_counter->attr.inherit_stat)
+                perf_counter_read_event(child_counter, child);
+
         child_val = atomic64_read(&child_counter->count);
 
         /*
@@ -3985,7 +4206,8 @@ static void sync_child_counter(struct perf_counter *child_counter,
 
 static void
 __perf_counter_exit_task(struct perf_counter *child_counter,
-                         struct perf_counter_context *child_ctx)
+                         struct perf_counter_context *child_ctx,
+                         struct task_struct *child)
 {
         struct perf_counter *parent_counter;
 
@@ -3999,7 +4221,7 @@ __perf_counter_exit_task(struct perf_counter *child_counter,
          * counters need to be zapped - but otherwise linger.
          */
         if (parent_counter) {
-                sync_child_counter(child_counter, parent_counter);
+                sync_child_counter(child_counter, child);
                 free_counter(child_counter);
         }
 }
@@ -4061,7 +4283,7 @@ void perf_counter_exit_task(struct task_struct *child)
 again:
         list_for_each_entry_safe(child_counter, tmp, &child_ctx->counter_list,
                                  list_entry)
-                __perf_counter_exit_task(child_counter, child_ctx);
+                __perf_counter_exit_task(child_counter, child_ctx, child);
 
         /*
          * If the last counter was a group counter, it will have appended all
diff --git a/kernel/pid.c b/kernel/pid.c
index 31310b5d3f50..5fa1db48d8b7 100644
--- a/kernel/pid.c
+++ b/kernel/pid.c
@@ -36,6 +36,7 @@
 #include <linux/pid_namespace.h>
 #include <linux/init_task.h>
 #include <linux/syscalls.h>
+#include <linux/kmemleak.h>
 
 #define pid_hashfn(nr, ns)      \
         hash_long((unsigned long)nr + (unsigned long)ns, pidhash_shift)
@@ -512,6 +513,12 @@ void __init pidhash_init(void)
         pid_hash = alloc_bootmem(pidhash_size * sizeof(*(pid_hash)));
         if (!pid_hash)
                 panic("Could not alloc pidhash!\n");
+        /*
+         * pid_hash contains references to allocated struct pid objects and it
+         * must be scanned by kmemleak to avoid false positives.
+         */
+        kmemleak_alloc(pid_hash, pidhash_size * sizeof(*(pid_hash)), 0,
+                       GFP_KERNEL);
         for (i = 0; i < pidhash_size; i++)
                 INIT_HLIST_HEAD(&pid_hash[i]);
 }
diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index 61c78b2c07ba..082c320e4dbf 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -181,8 +181,8 @@ int ptrace_attach(struct task_struct *task)
          * interference; SUID, SGID and LSM creds get determined differently
          * under ptrace.
          */
-        retval = mutex_lock_interruptible(&task->cred_guard_mutex);
-        if (retval < 0)
+        retval = -ERESTARTNOINTR;
+        if (mutex_lock_interruptible(&task->cred_guard_mutex))
                 goto out;
 
         task_lock(task);
diff --git a/kernel/rcutree.c b/kernel/rcutree.c
index 0dccfbba6d26..7717b95c2027 100644
--- a/kernel/rcutree.c
+++ b/kernel/rcutree.c
@@ -1533,7 +1533,7 @@ void __init __rcu_init(void)
         int j;
         struct rcu_node *rnp;
 
-        printk(KERN_WARNING "Experimental hierarchical RCU implementation.\n");
+        printk(KERN_INFO "Hierarchical RCU implementation.\n");
 #ifdef CONFIG_RCU_CPU_STALL_DETECTOR
         printk(KERN_INFO "RCU-based detection of stalled CPUs is enabled.\n");
 #endif /* #ifdef CONFIG_RCU_CPU_STALL_DETECTOR */
@@ -1546,7 +1546,6 @@ void __init __rcu_init(void)
                 rcu_cpu_notify(&rcu_nb, CPU_UP_PREPARE, (void *)(long)i);
         /* Register notifier for non-boot CPUs */
         register_cpu_notifier(&rcu_nb);
-        printk(KERN_WARNING "Experimental hierarchical RCU init done.\n");
 }
 
 module_param(blimit, int, 0);
diff --git a/kernel/resource.c b/kernel/resource.c
index ac5f3a36923f..78b087221c15 100644
--- a/kernel/resource.c
+++ b/kernel/resource.c
@@ -787,7 +787,7 @@ static int __init reserve_setup(char *str)
         static struct resource reserve[MAXRESERVE];
 
         for (;;) {
-                int io_start, io_num;
+                unsigned int io_start, io_num;
                 int x = reserved;
 
                 if (get_option (&str, &io_start) != 2)
diff --git a/kernel/sched.c b/kernel/sched.c
index 7c9098d186e6..01f55ada3598 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -6541,6 +6541,11 @@ SYSCALL_DEFINE0(sched_yield)
         return 0;
 }
 
+static inline int should_resched(void)
+{
+        return need_resched() && !(preempt_count() & PREEMPT_ACTIVE);
+}
+
 static void __cond_resched(void)
 {
 #ifdef CONFIG_DEBUG_SPINLOCK_SLEEP
@@ -6560,8 +6565,7 @@ static void __cond_resched(void)
 
 int __sched _cond_resched(void)
 {
-        if (need_resched() && !(preempt_count() & PREEMPT_ACTIVE) &&
-                                        system_state == SYSTEM_RUNNING) {
+        if (should_resched()) {
                 __cond_resched();
                 return 1;
         }
@@ -6579,12 +6583,12 @@ EXPORT_SYMBOL(_cond_resched);
  */
 int cond_resched_lock(spinlock_t *lock)
 {
-        int resched = need_resched() && system_state == SYSTEM_RUNNING;
+        int resched = should_resched();
         int ret = 0;
 
         if (spin_needbreak(lock) || resched) {
                 spin_unlock(lock);
-                if (resched && need_resched())
+                if (resched)
                         __cond_resched();
                 else
                         cpu_relax();
@@ -6599,7 +6603,7 @@ int __sched cond_resched_softirq(void)
 {
         BUG_ON(!in_softirq());
 
-        if (need_resched() && system_state == SYSTEM_RUNNING) {
+        if (should_resched()) {
                 local_bh_enable();
                 __cond_resched();
                 local_bh_disable();
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 62e4ff9968b5..98e02328c67d 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -335,7 +335,10 @@ static struct ctl_table kern_table[] = {
                 .data           = &sysctl_timer_migration,
                 .maxlen         = sizeof(unsigned int),
                 .mode           = 0644,
-                .proc_handler   = &proc_dointvec,
+                .proc_handler   = &proc_dointvec_minmax,
+                .strategy       = &sysctl_intvec,
+                .extra1         = &zero,
+                .extra2         = &one,
         },
 #endif
         {
@@ -744,6 +747,14 @@ static struct ctl_table kern_table[] = {
                 .proc_handler   = &proc_dointvec,
         },
         {
+                .ctl_name       = CTL_UNNUMBERED,
+                .procname       = "panic_on_io_nmi",
+                .data           = &panic_on_io_nmi,
+                .maxlen         = sizeof(int),
+                .mode           = 0644,
+                .proc_handler   = &proc_dointvec,
+        },
+        {
                 .ctl_name       = KERN_BOOTLOADER_TYPE,
                 .procname       = "bootloader_type",
                 .data           = &bootloader_type,
diff --git a/kernel/time/timer_stats.c b/kernel/time/timer_stats.c
index c994530d166d..4cde8b9c716f 100644
--- a/kernel/time/timer_stats.c
+++ b/kernel/time/timer_stats.c
@@ -96,7 +96,7 @@ static DEFINE_MUTEX(show_mutex);
 /*
  * Collection status, active/inactive:
  */
-static int __read_mostly active;
+int __read_mostly timer_stats_active;
 
 /*
  * Beginning/end timestamps of measurement:
@@ -242,7 +242,7 @@ void timer_stats_update_stats(void *timer, pid_t pid, void *startf,
         struct entry *entry, input;
         unsigned long flags;
 
-        if (likely(!active))
+        if (likely(!timer_stats_active))
                 return;
 
         lock = &per_cpu(lookup_lock, raw_smp_processor_id());
@@ -254,7 +254,7 @@ void timer_stats_update_stats(void *timer, pid_t pid, void *startf,
         input.timer_flag = timer_flag;
 
         spin_lock_irqsave(lock, flags);
-        if (!active)
+        if (!timer_stats_active)
                 goto out_unlock;
 
         entry = tstat_lookup(&input, comm);
@@ -290,7 +290,7 @@ static int tstats_show(struct seq_file *m, void *v)
         /*
          * If still active then calculate up to now:
          */
-        if (active)
+        if (timer_stats_active)
                 time_stop = ktime_get();
 
         time = ktime_sub(time_stop, time_start);
@@ -368,18 +368,18 @@ static ssize_t tstats_write(struct file *file, const char __user *buf,
         mutex_lock(&show_mutex);
         switch (ctl[0]) {
         case '0':
-                if (active) {
-                        active = 0;
+                if (timer_stats_active) {
+                        timer_stats_active = 0;
                         time_stop = ktime_get();
                         sync_access();
                 }
                 break;
         case '1':
-                if (!active) {
+                if (!timer_stats_active) {
                         reset_entries();
                         time_start = ktime_get();
                         smp_mb();
-                        active = 1;
+                        timer_stats_active = 1;
                 }
                 break;
         default:
diff --git a/kernel/timer.c b/kernel/timer.c
index 54d3912f8cad..0b36b9e5cc8b 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -380,6 +380,8 @@ static void timer_stats_account_timer(struct timer_list *timer)
 {
         unsigned int flag = 0;
 
+        if (likely(!timer->start_site))
+                return;
         if (unlikely(tbase_get_deferrable(timer->base)))
                 flag |= TIMER_STATS_FLAG_DEFERRABLE;
 
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index 1551f47e7669..019f380fd764 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -226,13 +226,13 @@ config BOOT_TRACER
           the timings of the initcalls and traces key events and the identity
           of tasks that can cause boot delays, such as context-switches.
 
-          Its aim is to be parsed by the /scripts/bootgraph.pl tool to
+          Its aim is to be parsed by the scripts/bootgraph.pl tool to
           produce pretty graphics about boot inefficiencies, giving a visual
           representation of the delays during initcalls - but the raw
           /debug/tracing/trace text output is readable too.
 
-          You must pass in ftrace=initcall to the kernel command line
-          to enable this on bootup.
+          You must pass in initcall_debug and ftrace=initcall to the kernel
+          command line to enable this on bootup.
 
 config TRACE_BRANCH_PROFILING
         bool
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 3718d55fb4c3..bce9e01a29c8 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -291,7 +291,9 @@ function_stat_next(void *v, int idx)
         pg = (struct ftrace_profile_page *)((unsigned long)rec & PAGE_MASK);
 
  again:
-        rec++;
+        if (idx != 0)
+                rec++;
+
         if ((void *)rec >= (void *)&pg->records[pg->index]) {
                 pg = pg->next;
                 if (!pg)
@@ -1417,10 +1419,20 @@ static void *t_hash_start(struct seq_file *m, loff_t *pos)
 {
         struct ftrace_iterator *iter = m->private;
         void *p = NULL;
+        loff_t l;
+
+        if (!(iter->flags & FTRACE_ITER_HASH))
+                *pos = 0;
 
         iter->flags |= FTRACE_ITER_HASH;
 
-        return t_hash_next(m, p, pos);
+        iter->hidx = 0;
+        for (l = 0; l <= *pos; ) {
+                p = t_hash_next(m, p, &l);
+                if (!p)
+                        break;
+        }
+        return p;
 }
 
 static int t_hash_show(struct seq_file *m, void *v)
@@ -1467,8 +1479,6 @@ t_next(struct seq_file *m, void *v, loff_t *pos)
                         iter->pg = iter->pg->next;
                         iter->idx = 0;
                         goto retry;
-                } else {
-                        iter->idx = -1;
                 }
         } else {
                 rec = &iter->pg->records[iter->idx++];
@@ -1497,6 +1507,7 @@ static void *t_start(struct seq_file *m, loff_t *pos)
 {
         struct ftrace_iterator *iter = m->private;
         void *p = NULL;
+        loff_t l;
 
         mutex_lock(&ftrace_lock);
         /*
@@ -1508,23 +1519,21 @@ static void *t_start(struct seq_file *m, loff_t *pos)
                 if (*pos > 0)
                         return t_hash_start(m, pos);
                 iter->flags |= FTRACE_ITER_PRINTALL;
-                (*pos)++;
                 return iter;
         }
 
         if (iter->flags & FTRACE_ITER_HASH)
                 return t_hash_start(m, pos);
 
-        if (*pos > 0) {
-                if (iter->idx < 0)
-                        return p;
-                (*pos)--;
-                iter->idx--;
+        iter->pg = ftrace_pages_start;
+        iter->idx = 0;
+        for (l = 0; l <= *pos; ) {
+                p = t_next(m, p, &l);
+                if (!p)
+                        break;
         }
 
-        p = t_next(m, p, pos);
-
-        if (!p)
+        if (!p && iter->flags & FTRACE_ITER_FILTER)
                 return t_hash_start(m, pos);
 
         return p;
@@ -2500,32 +2509,31 @@ int ftrace_graph_count;
 unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
 
 static void *
-g_next(struct seq_file *m, void *v, loff_t *pos)
+__g_next(struct seq_file *m, loff_t *pos)
 {
         unsigned long *array = m->private;
-        int index = *pos;
 
-        (*pos)++;
-
-        if (index >= ftrace_graph_count)
+        if (*pos >= ftrace_graph_count)
                 return NULL;
+        return &array[*pos];
+}
 
-        return &array[index];
+static void *
+g_next(struct seq_file *m, void *v, loff_t *pos)
+{
+        (*pos)++;
+        return __g_next(m, pos);
 }
 
 static void *g_start(struct seq_file *m, loff_t *pos)
 {
-        void *p = NULL;
-
         mutex_lock(&graph_lock);
 
         /* Nothing, tell g_show to print all functions are enabled */
         if (!ftrace_graph_count && !*pos)
                 return (void *)1;
 
-        p = g_next(m, p, pos);
-
-        return p;
+        return __g_next(m, pos);
 }
 
 static void g_stop(struct seq_file *m, void *p)
@@ -3152,10 +3160,10 @@ ftrace_enable_sysctl(struct ctl_table *table, int write,
 
         ret  = proc_dointvec(table, write, file, buffer, lenp, ppos);
 
-        if (ret || !write || (last_ftrace_enabled == ftrace_enabled))
+        if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled))
                 goto out;
 
-        last_ftrace_enabled = ftrace_enabled;
+        last_ftrace_enabled = !!ftrace_enabled;
 
         if (ftrace_enabled) {
 
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 04dac2638258..bf27bb7a63e2 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -1563,6 +1563,8 @@ rb_reserve_next_event(struct ring_buffer_per_cpu *cpu_buffer,
         return NULL;
 }
 
+#ifdef CONFIG_TRACING
+
 #define TRACE_RECURSIVE_DEPTH 16
 
 static int trace_recursive_lock(void)
@@ -1593,6 +1595,13 @@ static void trace_recursive_unlock(void)
         current->trace_recursion--;
 }
 
+#else
+
+#define trace_recursive_lock()          (0)
+#define trace_recursive_unlock()        do { } while (0)
+
+#endif
+
 static DEFINE_PER_CPU(int, rb_need_resched);
 
 /**
@@ -3104,6 +3113,7 @@ int ring_buffer_read_page(struct ring_buffer *buffer,
 }
 EXPORT_SYMBOL_GPL(ring_buffer_read_page);
 
+#ifdef CONFIG_TRACING
 static ssize_t
 rb_simple_read(struct file *filp, char __user *ubuf,
                size_t cnt, loff_t *ppos)
@@ -3171,6 +3181,7 @@ static __init int rb_init_debugfs(void)
 }
 
 fs_initcall(rb_init_debugfs);
+#endif
 
 #ifdef CONFIG_HOTPLUG_CPU
 static int rb_cpu_notify(struct notifier_block *self,
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 076fa6f0ee48..3aa0a0dfdfa8 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -284,13 +284,12 @@ void trace_wake_up(void)
 static int __init set_buf_size(char *str)
 {
         unsigned long buf_size;
-        int ret;
 
         if (!str)
                 return 0;
-        ret = strict_strtoul(str, 0, &buf_size);
+        buf_size = memparse(str, &str);
         /* nr_entries can not be zero */
-        if (ret < 0 || buf_size == 0)
+        if (buf_size == 0)
                 return 0;
         trace_buf_size = buf_size;
         return 1;
@@ -2053,25 +2052,23 @@ static int tracing_open(struct inode *inode, struct file *file)
 static void *
 t_next(struct seq_file *m, void *v, loff_t *pos)
 {
-        struct tracer *t = m->private;
+        struct tracer *t = v;
 
         (*pos)++;
 
         if (t)
                 t = t->next;
 
-        m->private = t;
-
         return t;
 }
 
 static void *t_start(struct seq_file *m, loff_t *pos)
 {
-        struct tracer *t = m->private;
+        struct tracer *t;
         loff_t l = 0;
 
         mutex_lock(&trace_types_lock);
-        for (; t && l < *pos; t = t_next(m, t, &l))
+        for (t = trace_types; t && l < *pos; t = t_next(m, t, &l))
                 ;
 
         return t;
@@ -2107,18 +2104,10 @@ static struct seq_operations show_traces_seq_ops = {
 
 static int show_traces_open(struct inode *inode, struct file *file)
 {
-        int ret;
-
         if (tracing_disabled)
                 return -ENODEV;
 
-        ret = seq_open(file, &show_traces_seq_ops);
-        if (!ret) {
-                struct seq_file *m = file->private_data;
-                m->private = trace_types;
-        }
-
-        return ret;
+        return seq_open(file, &show_traces_seq_ops);
 }
 
 static ssize_t
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 6e735d4771f8..3548ae5cc780 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -597,6 +597,7 @@ print_graph_function(struct trace_iterator *iter)
 
 extern struct pid *ftrace_pid_trace;
 
+#ifdef CONFIG_FUNCTION_TRACER
 static inline int ftrace_trace_task(struct task_struct *task)
 {
         if (!ftrace_pid_trace)
@@ -604,6 +605,12 @@ static inline int ftrace_trace_task(struct task_struct *task)
 
         return test_tsk_trace_trace(task);
 }
+#else
+static inline int ftrace_trace_task(struct task_struct *task)
+{
+        return 1;
+}
+#endif
 
 /*
  * trace_iterator_flags is an enumeration that defines bit
diff --git a/kernel/trace/trace_event_types.h b/kernel/trace/trace_event_types.h
index 5e32e375134d..6db005e12487 100644
--- a/kernel/trace/trace_event_types.h
+++ b/kernel/trace/trace_event_types.h
@@ -26,6 +26,9 @@ TRACE_EVENT_FORMAT(funcgraph_exit, TRACE_GRAPH_RET,
                    ftrace_graph_ret_entry, ignore,
         TRACE_STRUCT(
                 TRACE_FIELD(unsigned long, ret.func, func)
+                TRACE_FIELD(unsigned long long, ret.calltime, calltime)
+                TRACE_FIELD(unsigned long long, ret.rettime, rettime)
+                TRACE_FIELD(unsigned long, ret.overrun, overrun)
                 TRACE_FIELD(int, ret.depth, depth)
         ),
         TP_RAW_FMT("<-- %lx (%d)")
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index aa08be69a1b6..53c8fd376a88 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -300,10 +300,18 @@ t_next(struct seq_file *m, void *v, loff_t *pos)
 
 static void *t_start(struct seq_file *m, loff_t *pos)
 {
+        struct ftrace_event_call *call = NULL;
+        loff_t l;
+
         mutex_lock(&event_mutex);
-        if (*pos == 0)
-                m->private = ftrace_events.next;
-        return t_next(m, NULL, pos);
+
+        m->private = ftrace_events.next;
+        for (l = 0; l <= *pos; ) {
+                call = t_next(m, NULL, &l);
+                if (!call)
+                        break;
+        }
+        return call;
 }
 
 static void *
@@ -332,10 +340,18 @@ s_next(struct seq_file *m, void *v, loff_t *pos)
 
 static void *s_start(struct seq_file *m, loff_t *pos)
 {
+        struct ftrace_event_call *call = NULL;
+        loff_t l;
+
         mutex_lock(&event_mutex);
-        if (*pos == 0)
-                m->private = ftrace_events.next;
-        return s_next(m, NULL, pos);
+
+        m->private = ftrace_events.next;
+        for (l = 0; l <= *pos; ) {
+                call = s_next(m, NULL, &l);
+                if (!call)
+                        break;
+        }
+        return call;
 }
 
 static int t_show(struct seq_file *m, void *v)
diff --git a/kernel/trace/trace_functions.c b/kernel/trace/trace_functions.c
index 90f134764837..7402144bff21 100644
--- a/kernel/trace/trace_functions.c
+++ b/kernel/trace/trace_functions.c
@@ -302,8 +302,7 @@ ftrace_trace_onoff_print(struct seq_file *m, unsigned long ip,
         if (count == -1)
                 seq_printf(m, ":unlimited\n");
         else
-                seq_printf(m, ":count=%ld", count);
-        seq_putc(m, '\n');
+                seq_printf(m, ":count=%ld\n", count);
 
         return 0;
 }
diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c
index 7938f3ae93e3..e0c2545622e8 100644
--- a/kernel/trace/trace_output.c
+++ b/kernel/trace/trace_output.c
@@ -27,8 +27,7 @@ void trace_print_seq(struct seq_file *m, struct trace_seq *s)
 {
         int len = s->len >= PAGE_SIZE ? PAGE_SIZE - 1 : s->len;
 
-        s->buffer[len] = 0;
-        seq_puts(m, s->buffer);
+        seq_write(m, s->buffer, len);
 
         trace_seq_init(s);
 }
diff --git a/kernel/trace/trace_printk.c b/kernel/trace/trace_printk.c
index 9bece9687b62..7b6278110827 100644
--- a/kernel/trace/trace_printk.c
+++ b/kernel/trace/trace_printk.c
@@ -155,25 +155,19 @@ int __ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap)
 EXPORT_SYMBOL_GPL(__ftrace_vprintk);
 
 static void *
-t_next(struct seq_file *m, void *v, loff_t *pos)
+t_start(struct seq_file *m, loff_t *pos)
 {
-        const char **fmt = m->private;
-        const char **next = fmt;
-
-        (*pos)++;
+        const char **fmt = __start___trace_bprintk_fmt + *pos;
 
         if ((unsigned long)fmt >= (unsigned long)__stop___trace_bprintk_fmt)
                 return NULL;
-
-        next = fmt;
-        m->private = ++next;
-
         return fmt;
 }
 
-static void *t_start(struct seq_file *m, loff_t *pos)
+static void *t_next(struct seq_file *m, void * v, loff_t *pos)
 {
-        return t_next(m, NULL, pos);
+        (*pos)++;
+        return t_start(m, pos);
 }
 
 static int t_show(struct seq_file *m, void *v)
@@ -224,15 +218,7 @@ static const struct seq_operations show_format_seq_ops = {
 static int
 ftrace_formats_open(struct inode *inode, struct file *file)
 {
-        int ret;
-
-        ret = seq_open(file, &show_format_seq_ops);
-        if (!ret) {
-                struct seq_file *m = file->private_data;
-
-                m->private = __start___trace_bprintk_fmt;
-        }
-        return ret;
+        return seq_open(file, &show_format_seq_ops);
 }
 
 static const struct file_operations ftrace_formats_fops = {
diff --git a/kernel/trace/trace_stack.c b/kernel/trace/trace_stack.c
index 2d7aebd71dbd..e644af910124 100644
--- a/kernel/trace/trace_stack.c
+++ b/kernel/trace/trace_stack.c
@@ -326,10 +326,10 @@ stack_trace_sysctl(struct ctl_table *table, int write,
         ret = proc_dointvec(table, write, file, buffer, lenp, ppos);
 
         if (ret || !write ||
-            (last_stack_tracer_enabled == stack_tracer_enabled))
+            (last_stack_tracer_enabled == !!stack_tracer_enabled))
                 goto out;
 
-        last_stack_tracer_enabled = stack_tracer_enabled;
+        last_stack_tracer_enabled = !!stack_tracer_enabled;
 
         if (stack_tracer_enabled)
                 register_ftrace_function(&trace_ops);
diff --git a/kernel/trace/trace_stat.c b/kernel/trace/trace_stat.c
index c00643733f4c..e66f5e493342 100644
--- a/kernel/trace/trace_stat.c
+++ b/kernel/trace/trace_stat.c
@@ -199,17 +199,13 @@ static void *stat_seq_start(struct seq_file *s, loff_t *pos)
         mutex_lock(&session->stat_mutex);
 
         /* If we are in the beginning of the file, print the headers */
-        if (!*pos && session->ts->stat_headers) {
-                (*pos)++;
+        if (!*pos && session->ts->stat_headers)
                 return SEQ_START_TOKEN;
-        }
 
         node = rb_first(&session->stat_root);
         for (i = 0; node && i < *pos; i++)
                 node = rb_next(node);
 
-        (*pos)++;
-
         return node;
 }