Merge branch 'linus' into x86/apic

Conflicts:
	arch/x86/mach-default/setup.c

Semantic conflict resolution:
	arch/x86/kernel/setup.c

Signed-off-by: Ingo Molnar <mingo@elte.hu>

4 files changed, 59 insertions, 5 deletions

diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index e2a4ff6fc3a6..34e707e5ab87 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -52,6 +52,7 @@ config FUNCTION_TRACER
         depends on HAVE_FUNCTION_TRACER
         depends on DEBUG_KERNEL
         select FRAME_POINTER
+        select KALLSYMS
         select TRACING
         select CONTEXT_SWITCH_TRACER
         help
@@ -238,6 +239,7 @@ config STACK_TRACER
         depends on DEBUG_KERNEL
         select FUNCTION_TRACER
         select STACKTRACE
+        select KALLSYMS
         help
           This special tracer records the maximum stack footprint of the
           kernel and displays it in debugfs/tracing/stack_trace.
@@ -302,4 +304,27 @@ config FTRACE_STARTUP_TEST
           functioning properly. It will do tests on all the configured
           tracers of ftrace.
 
+config MMIOTRACE
+        bool "Memory mapped IO tracing"
+        depends on HAVE_MMIOTRACE_SUPPORT && DEBUG_KERNEL && PCI
+        select TRACING
+        help
+          Mmiotrace traces Memory Mapped I/O access and is meant for
+          debugging and reverse engineering. It is called from the ioremap
+          implementation and works via page faults. Tracing is disabled by
+          default and can be enabled at run-time.
+
+          See Documentation/tracers/mmiotrace.txt.
+          If you are not helping to develop drivers, say N.
+
+config MMIOTRACE_TEST
+        tristate "Test module for mmiotrace"
+        depends on MMIOTRACE && m
+        help
+          This is a dumb module for testing mmiotrace. It is very dangerous
+          as it will write garbage to IO memory starting at a given address.
+          However, it should be safe to use on e.g. unused portion of VRAM.
+
+          Say N, unless you absolutely know what you are doing.
+
 endmenu
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 9a236ffe2aa4..fdf913dfc7e8 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -2033,7 +2033,7 @@ free:
 static int start_graph_tracing(void)
 {
         struct ftrace_ret_stack **ret_stack_list;
-        int ret;
+        int ret, cpu;
 
         ret_stack_list = kmalloc(FTRACE_RETSTACK_ALLOC_SIZE *
                                 sizeof(struct ftrace_ret_stack *),
@@ -2042,6 +2042,10 @@ static int start_graph_tracing(void)
         if (!ret_stack_list)
                 return -ENOMEM;
 
+        /* The cpu_boot init_task->ret_stack will never be freed */
+        for_each_online_cpu(cpu)
+                ftrace_graph_init_task(idle_task(cpu));
+
         do {
                 ret = alloc_retstack_tasklist(ret_stack_list);
         } while (ret == -EAGAIN);
diff --git a/kernel/trace/trace_mmiotrace.c b/kernel/trace/trace_mmiotrace.c
index fffcb069f1dc..80e503ef6136 100644
--- a/kernel/trace/trace_mmiotrace.c
+++ b/kernel/trace/trace_mmiotrace.c
@@ -9,6 +9,7 @@
 #include <linux/kernel.h>
 #include <linux/mmiotrace.h>
 #include <linux/pci.h>
+#include <asm/atomic.h>
 
 #include "trace.h"
 
@@ -19,6 +20,7 @@ struct header_iter {
 static struct trace_array *mmio_trace_array;
 static bool overrun_detected;
 static unsigned long prev_overruns;
+static atomic_t dropped_count;
 
 static void mmio_reset_data(struct trace_array *tr)
 {
@@ -121,11 +123,11 @@ static void mmio_close(struct trace_iterator *iter)
 
 static unsigned long count_overruns(struct trace_iterator *iter)
 {
-        unsigned long cnt = 0;
+        unsigned long cnt = atomic_xchg(&dropped_count, 0);
         unsigned long over = ring_buffer_overruns(iter->tr->buffer);
 
         if (over > prev_overruns)
-                cnt = over - prev_overruns;
+                cnt += over - prev_overruns;
         prev_overruns = over;
         return cnt;
 }
@@ -310,8 +312,10 @@ static void __trace_mmiotrace_rw(struct trace_array *tr,
 
         event   = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry),
                                            &irq_flags);
-        if (!event)
+        if (!event) {
+                atomic_inc(&dropped_count);
                 return;
+        }
         entry   = ring_buffer_event_data(event);
         tracing_generic_entry_update(&entry->ent, 0, preempt_count());
         entry->ent.type                 = TRACE_MMIO_RW;
@@ -338,8 +342,10 @@ static void __trace_mmiotrace_map(struct trace_array *tr,
 
         event   = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry),
                                            &irq_flags);
-        if (!event)
+        if (!event) {
+                atomic_inc(&dropped_count);
                 return;
+        }
         entry   = ring_buffer_event_data(event);
         tracing_generic_entry_update(&entry->ent, 0, preempt_count());
         entry->ent.type                 = TRACE_MMIO_MAP;
diff --git a/kernel/trace/trace_selftest.c b/kernel/trace/trace_selftest.c
index 88c8eb70f54a..bc8e80a86bca 100644
--- a/kernel/trace/trace_selftest.c
+++ b/kernel/trace/trace_selftest.c
@@ -23,10 +23,20 @@ static int trace_test_buffer_cpu(struct trace_array *tr, int cpu)
 {
         struct ring_buffer_event *event;
         struct trace_entry *entry;
+        unsigned int loops = 0;
 
         while ((event = ring_buffer_consume(tr->buffer, cpu, NULL))) {
                 entry = ring_buffer_event_data(event);
 
+                /*
+                 * The ring buffer is a size of trace_buf_size, if
+                 * we loop more than the size, there's something wrong
+                 * with the ring buffer.
+                 */
+                if (loops++ > trace_buf_size) {
+                        printk(KERN_CONT ".. bad ring buffer ");
+                        goto failed;
+                }
                 if (!trace_valid_entry(entry)) {
                         printk(KERN_CONT ".. invalid entry %d ",
                                 entry->type);
@@ -57,11 +67,20 @@ static int trace_test_buffer(struct trace_array *tr, unsigned long *count)
 
         cnt = ring_buffer_entries(tr->buffer);
 
+        /*
+         * The trace_test_buffer_cpu runs a while loop to consume all data.
+         * If the calling tracer is broken, and is constantly filling
+         * the buffer, this will run forever, and hard lock the box.
+         * We disable the ring buffer while we do this test to prevent
+         * a hard lock up.
+         */
+        tracing_off();
         for_each_possible_cpu(cpu) {
                 ret = trace_test_buffer_cpu(tr, cpu);
                 if (ret)
                         break;
         }
+        tracing_on();
         __raw_spin_unlock(&ftrace_max_lock);
         local_irq_restore(flags);