Merge branch 'tracing-fixes-for-linus' of...

Merge branch 'tracing-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'tracing-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  kernel/profile.c: Switch /proc/irq/prof_cpu_mask to seq_file
  tracing: Export trace_profile_buf symbols
  tracing/events: use list_for_entry_continue
  tracing: remove max_tracer_type_len
  function-graph: use ftrace_graph_funcs directly
  tracing: Remove markers
  tracing: Allocate the ftrace event profile buffer dynamically
  tracing: Factorize the events profile accounting

Documentation/markers.txt

- 	             Using the Linux Kernel Markers
-
-			    Mathieu Desnoyers
-
-
-This document introduces Linux Kernel Markers and their use. It provides
-examples of how to insert markers in the kernel and connect probe functions to
-them and provides some examples of probe functions.
-
-
-* Purpose of markers
-
-A marker placed in code provides a hook to call a function (probe) that you can
-provide at runtime. A marker can be "on" (a probe is connected to it) or "off"
-(no probe is attached). When a marker is "off" it has no effect, except for
-adding a tiny time penalty (checking a condition for a branch) and space
-penalty (adding a few bytes for the function call at the end of the
-instrumented function and adds a data structure in a separate section).  When a
-marker is "on", the function you provide is called each time the marker is
-executed, in the execution context of the caller. When the function provided
-ends its execution, it returns to the caller (continuing from the marker site).
-
-You can put markers at important locations in the code. Markers are
-lightweight hooks that can pass an arbitrary number of parameters,
-described in a printk-like format string, to the attached probe function.
-
-They can be used for tracing and performance accounting.
-
-
-* Usage
-
-In order to use the macro trace_mark, you should include linux/marker.h.
-
-#include <linux/marker.h>
-
-And,
-
-trace_mark(subsystem_event, "myint %d mystring %s", someint, somestring);
-Where :
-- subsystem_event is an identifier unique to your event
-    - subsystem is the name of your subsystem.
-    - event is the name of the event to mark.
-- "myint %d mystring %s" is the formatted string for the serializer. "myint" and
-  "mystring" are repectively the field names associated with the first and
-  second parameter.
-- someint is an integer.
-- somestring is a char pointer.
-
-Connecting a function (probe) to a marker is done by providing a probe (function
-to call) for the specific marker through marker_probe_register() and can be
-activated by calling marker_arm(). Marker deactivation can be done by calling
-marker_disarm() as many times as marker_arm() has been called. Removing a probe
-is done through marker_probe_unregister(); it will disarm the probe.
-
-marker_synchronize_unregister() must be called between probe unregistration and
-the first occurrence of
-- the end of module exit function,
-  to make sure there is no caller left using the probe;
-- the free of any resource used by the probes,
-  to make sure the probes wont be accessing invalid data.
-This, and the fact that preemption is disabled around the probe call, make sure
-that probe removal and module unload are safe. See the "Probe example" section
-below for a sample probe module.
-
-The marker mechanism supports inserting multiple instances of the same marker.
-Markers can be put in inline functions, inlined static functions, and
-unrolled loops as well as regular functions.
-
-The naming scheme "subsystem_event" is suggested here as a convention intended
-to limit collisions. Marker names are global to the kernel: they are considered
-as being the same whether they are in the core kernel image or in modules.
-Conflicting format strings for markers with the same name will cause the markers
-to be detected to have a different format string not to be armed and will output
-a printk warning which identifies the inconsistency:
-
-"Format mismatch for probe probe_name (format), marker (format)"
-
-Another way to use markers is to simply define the marker without generating any
-function call to actually call into the marker. This is useful in combination
-with tracepoint probes in a scheme like this :
-
-void probe_tracepoint_name(unsigned int arg1, struct task_struct *tsk);
-
-DEFINE_MARKER_TP(marker_eventname, tracepoint_name, probe_tracepoint_name,
-	"arg1 %u pid %d");
-
-notrace void probe_tracepoint_name(unsigned int arg1, struct task_struct *tsk)
-{
-	struct marker *marker = &GET_MARKER(kernel_irq_entry);
-	/* write data to trace buffers ... */
-}
-
-* Probe / marker example
-
-See the example provided in samples/markers/src
-
-Compile them with your kernel.
-
-Run, as root :
-modprobe marker-example (insmod order is not important)
-modprobe probe-example
-cat /proc/marker-example (returns an expected error)
-rmmod marker-example probe-example
-dmesg

arch/powerpc/platforms/cell/spufs/file.c

@@ -29,7 +29,6 @@
 #include <linux/poll.h>
 #include <linux/ptrace.h>
 #include <linux/seq_file.h>
-#include <linux/marker.h>
 
 #include <asm/io.h>
 #include <asm/time.h>

arch/powerpc/platforms/cell/spufs/sched.c

@@ -39,7 +39,6 @@
 #include <linux/pid_namespace.h>
 #include <linux/proc_fs.h>
 #include <linux/seq_file.h>
-#include <linux/marker.h>
 
 #include <asm/io.h>
 #include <asm/mmu_context.h>

include/linux/ftrace_event.h

@@ -4,6 +4,7 @@
 #include <linux/ring_buffer.h>
 #include <linux/trace_seq.h>
 #include <linux/percpu.h>
+#include <linux/hardirq.h>
 
 struct trace_array;
 struct tracer;
@@ -130,10 +131,15 @@ struct ftrace_event_call {
 	void			*data;
 
 	atomic_t		profile_count;
-	int			(*profile_enable)(struct ftrace_event_call *);
-	void			(*profile_disable)(struct ftrace_event_call *);
+	int			(*profile_enable)(void);
+	void			(*profile_disable)(void);
 };
 
+#define FTRACE_MAX_PROFILE_SIZE	2048
+
+extern char			*trace_profile_buf;
+extern char			*trace_profile_buf_nmi;
+
 #define MAX_FILTER_PRED		32
 #define MAX_FILTER_STR_VAL	256	/* Should handle KSYM_SYMBOL_LEN */
 

include/linux/kvm_host.h

@@ -15,7 +15,6 @@
 #include <linux/sched.h>
 #include <linux/mm.h>
 #include <linux/preempt.h>
-#include <linux/marker.h>
 #include <linux/msi.h>
 #include <asm/signal.h>
 

include/linux/marker.h

-#ifndef _LINUX_MARKER_H
-#define _LINUX_MARKER_H
-
-/*
- * Code markup for dynamic and static tracing.
- *
- * See Documentation/marker.txt.
- *
- * (C) Copyright 2006 Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
- *
- * This file is released under the GPLv2.
- * See the file COPYING for more details.
- */
-
-#include <stdarg.h>
-#include <linux/types.h>
-
-struct module;
-struct marker;
-
-/**
- * marker_probe_func - Type of a marker probe function
- * @probe_private: probe private data
- * @call_private: call site private data
- * @fmt: format string
- * @args: variable argument list pointer. Use a pointer to overcome C's
- *        inability to pass this around as a pointer in a portable manner in
- *        the callee otherwise.
- *
- * Type of marker probe functions. They receive the mdata and need to parse the
- * format string to recover the variable argument list.
- */
-typedef void marker_probe_func(void *probe_private, void *call_private,
-		const char *fmt, va_list *args);
-
-struct marker_probe_closure {
-	marker_probe_func *func;	/* Callback */
-	void *probe_private;		/* Private probe data */
-};
-
-struct marker {
-	const char *name;	/* Marker name */
-	const char *format;	/* Marker format string, describing the
-				 * variable argument list.
-				 */
-	char state;		/* Marker state. */
-	char ptype;		/* probe type : 0 : single, 1 : multi */
-				/* Probe wrapper */
-	void (*call)(const struct marker *mdata, void *call_private, ...);
-	struct marker_probe_closure single;
-	struct marker_probe_closure *multi;
-	const char *tp_name;	/* Optional tracepoint name */
-	void *tp_cb;		/* Optional tracepoint callback */
-} __attribute__((aligned(8)));
-
-#ifdef CONFIG_MARKERS
-
-#define _DEFINE_MARKER(name, tp_name_str, tp_cb, format)		\
-		static const char __mstrtab_##name[]			\
-		__attribute__((section("__markers_strings")))		\
-		= #name "\0" format;					\
-		static struct marker __mark_##name			\
-		__attribute__((section("__markers"), aligned(8))) =	\
-		{ __mstrtab_##name, &__mstrtab_##name[sizeof(#name)],	\
-		  0, 0, marker_probe_cb, { __mark_empty_function, NULL},\
-		  NULL, tp_name_str, tp_cb }
-
-#define DEFINE_MARKER(name, format)					\
-		_DEFINE_MARKER(name, NULL, NULL, format)
-
-#define DEFINE_MARKER_TP(name, tp_name, tp_cb, format)			\
-		_DEFINE_MARKER(name, #tp_name, tp_cb, format)
-
-/*
- * Note : the empty asm volatile with read constraint is used here instead of a
- * "used" attribute to fix a gcc 4.1.x bug.
- * Make sure the alignment of the structure in the __markers section will
- * not add unwanted padding between the beginning of the section and the
- * structure. Force alignment to the same alignment as the section start.
- *
- * The "generic" argument controls which marker enabling mechanism must be used.
- * If generic is true, a variable read is used.
- * If generic is false, immediate values are used.
- */
-#define __trace_mark(generic, name, call_private, format, args...)	\
-	do {								\
-		DEFINE_MARKER(name, format);				\
-		__mark_check_format(format, ## args);			\
-		if (unlikely(__mark_##name.state)) {			\
-			(*__mark_##name.call)				\
-				(&__mark_##name, call_private, ## args);\
-		}							\
-	} while (0)
-
-#define __trace_mark_tp(name, call_private, tp_name, tp_cb, format, args...) \
-	do {								\
-		void __check_tp_type(void)				\
-		{							\
-			register_trace_##tp_name(tp_cb);		\
-		}							\
-		DEFINE_MARKER_TP(name, tp_name, tp_cb, format);		\
-		__mark_check_format(format, ## args);			\
-		(*__mark_##name.call)(&__mark_##name, call_private,	\
-					## args);			\
-	} while (0)
-
-extern void marker_update_probe_range(struct marker *begin,
-	struct marker *end);
-
-#define GET_MARKER(name)	(__mark_##name)
-
-#else /* !CONFIG_MARKERS */
-#define DEFINE_MARKER(name, tp_name, tp_cb, format)
-#define __trace_mark(generic, name, call_private, format, args...) \
-		__mark_check_format(format, ## args)
-#define __trace_mark_tp(name, call_private, tp_name, tp_cb, format, args...) \
-	do {								\
-		void __check_tp_type(void)				\
-		{							\
-			register_trace_##tp_name(tp_cb);		\
-		}							\
-		__mark_check_format(format, ## args);			\
-	} while (0)
-static inline void marker_update_probe_range(struct marker *begin,
-	struct marker *end)
-{ }
-#define GET_MARKER(name)
-#endif /* CONFIG_MARKERS */
-
-/**
- * trace_mark - Marker using code patching
- * @name: marker name, not quoted.
- * @format: format string
- * @args...: variable argument list
- *
- * Places a marker using optimized code patching technique (imv_read())
- * to be enabled when immediate values are present.
- */
-#define trace_mark(name, format, args...) \
-	__trace_mark(0, name, NULL, format, ## args)
-
-/**
- * _trace_mark - Marker using variable read
- * @name: marker name, not quoted.
- * @format: format string
- * @args...: variable argument list
- *
- * Places a marker using a standard memory read (_imv_read()) to be
- * enabled. Should be used for markers in code paths where instruction
- * modification based enabling is not welcome. (__init and __exit functions,
- * lockdep, some traps, printk).
- */
-#define _trace_mark(name, format, args...) \
-	__trace_mark(1, name, NULL, format, ## args)
-
-/**
- * trace_mark_tp - Marker in a tracepoint callback
- * @name: marker name, not quoted.
- * @tp_name: tracepoint name, not quoted.
- * @tp_cb: tracepoint callback. Should have an associated global symbol so it
- *         is not optimized away by the compiler (should not be static).
- * @format: format string
- * @args...: variable argument list
- *
- * Places a marker in a tracepoint callback.
- */
-#define trace_mark_tp(name, tp_name, tp_cb, format, args...)	\
-	__trace_mark_tp(name, NULL, tp_name, tp_cb, format, ## args)
-
-/**
- * MARK_NOARGS - Format string for a marker with no argument.
- */
-#define MARK_NOARGS " "
-
-/* To be used for string format validity checking with gcc */
-static inline void __printf(1, 2) ___mark_check_format(const char *fmt, ...)
-{
-}
-
-#define __mark_check_format(format, args...)				\
-	do {								\
-		if (0)							\
-			___mark_check_format(format, ## args);		\
-	} while (0)
-
-extern marker_probe_func __mark_empty_function;
-
-extern void marker_probe_cb(const struct marker *mdata,
-	void *call_private, ...);
-
-/*
- * Connect a probe to a marker.
- * private data pointer must be a valid allocated memory address, or NULL.
- */
-extern int marker_probe_register(const char *name, const char *format,
-				marker_probe_func *probe, void *probe_private);
-
-/*
- * Returns the private data given to marker_probe_register.
- */
-extern int marker_probe_unregister(const char *name,
-	marker_probe_func *probe, void *probe_private);
-/*
- * Unregister a marker by providing the registered private data.
- */
-extern int marker_probe_unregister_private_data(marker_probe_func *probe,
-	void *probe_private);
-
-extern void *marker_get_private_data(const char *name, marker_probe_func *probe,
-	int num);
-
-/*
- * marker_synchronize_unregister must be called between the last marker probe
- * unregistration and the first one of
- * - the end of module exit function
- * - the free of any resource used by the probes
- * to ensure the code and data are valid for any possibly running probes.
- */
-#define marker_synchronize_unregister() synchronize_sched()
-
-#endif

include/linux/module.h

@@ -15,7 +15,6 @@
 #include <linux/stringify.h>
 #include <linux/kobject.h>
 #include <linux/moduleparam.h>
-#include <linux/marker.h>
 #include <linux/tracepoint.h>
 
 #include <asm/local.h>
@@ -327,10 +326,6 @@ struct module
 	/* The command line arguments (may be mangled).  People like
 	   keeping pointers to this stuff */
 	char *args;
-#ifdef CONFIG_MARKERS
-	struct marker *markers;
-	unsigned int num_markers;
-#endif
 #ifdef CONFIG_TRACEPOINTS
 	struct tracepoint *tracepoints;
 	unsigned int num_tracepoints;
@@ -535,8 +530,6 @@ int unregister_module_notifier(struct notifier_block * nb);
 
 extern void print_modules(void);
 
-extern void module_update_markers(void);
-
 extern void module_update_tracepoints(void);
 extern int module_get_iter_tracepoints(struct tracepoint_iter *iter);
 
@@ -651,10 +644,6 @@ static inline void print_modules(void)
 {
 }
 
-static inline void module_update_markers(void)
-{
-}
-
 static inline void module_update_tracepoints(void)
 {
 }

include/linux/syscalls.h

@@ -100,33 +100,25 @@ struct perf_counter_attr;
 
 #ifdef CONFIG_EVENT_PROFILE
 #define TRACE_SYS_ENTER_PROFILE(sname)					       \
-static int prof_sysenter_enable_##sname(struct ftrace_event_call *event_call)  \
+static int prof_sysenter_enable_##sname(void)				       \
 {									       \
-	int ret = 0;							       \
-	if (!atomic_inc_return(&event_enter_##sname.profile_count))	       \
-		ret = reg_prof_syscall_enter("sys"#sname);		       \
-	return ret;							       \
+	return reg_prof_syscall_enter("sys"#sname);			       \
 }									       \
 									       \
-static void prof_sysenter_disable_##sname(struct ftrace_event_call *event_call)\
+static void prof_sysenter_disable_##sname(void)				       \
 {									       \
-	if (atomic_add_negative(-1, &event_enter_##sname.profile_count))       \
-		unreg_prof_syscall_enter("sys"#sname);			       \
+	unreg_prof_syscall_enter("sys"#sname);				       \
 }
 
 #define TRACE_SYS_EXIT_PROFILE(sname)					       \
-static int prof_sysexit_enable_##sname(struct ftrace_event_call *event_call)   \
+static int prof_sysexit_enable_##sname(void)				       \
 {									       \
-	int ret = 0;							       \
-	if (!atomic_inc_return(&event_exit_##sname.profile_count))	       \
-		ret = reg_prof_syscall_exit("sys"#sname);		       \
-	return ret;							       \
+	return reg_prof_syscall_exit("sys"#sname);			       \
 }									       \
 									       \
-static void prof_sysexit_disable_##sname(struct ftrace_event_call *event_call) \
+static void prof_sysexit_disable_##sname(void)				       \
 {                                                                              \
-	if (atomic_add_negative(-1, &event_exit_##sname.profile_count))	       \
-		unreg_prof_syscall_exit("sys"#sname);			       \
+	unreg_prof_syscall_exit("sys"#sname);				       \
 }
 
 #define TRACE_SYS_ENTER_PROFILE_INIT(sname)				       \

include/trace/ftrace.h

@@ -382,20 +382,14 @@ static inline int ftrace_get_offsets_##call(				\
  *
  * NOTE: The insertion profile callback (ftrace_profile_<call>) is defined later
  *
- * static int ftrace_profile_enable_<call>(struct ftrace_event_call *event_call)
+ * static int ftrace_profile_enable_<call>(void)
  * {
- * 	int ret = 0;
- *
- * 	if (!atomic_inc_return(&event_call->profile_count))
- * 		ret = register_trace_<call>(ftrace_profile_<call>);
- *
- * 	return ret;
+ * 	return register_trace_<call>(ftrace_profile_<call>);
  * }
  *
- * static void ftrace_profile_disable_<call>(struct ftrace_event_call *event_call)
+ * static void ftrace_profile_disable_<call>(void)
  * {
- * 	if (atomic_add_negative(-1, &event->call->profile_count))
- * 		unregister_trace_<call>(ftrace_profile_<call>);
+ * 	unregister_trace_<call>(ftrace_profile_<call>);
  * }
  *
  */
@@ -405,20 +399,14 @@ static inline int ftrace_get_offsets_##call(				\
 									\
 static void ftrace_profile_##call(proto);				\
 									\
-static int ftrace_profile_enable_##call(struct ftrace_event_call *event_call) \
+static int ftrace_profile_enable_##call(void)				\
 {									\
-	int ret = 0;							\
-									\
-	if (!atomic_inc_return(&event_call->profile_count))		\
-		ret = register_trace_##call(ftrace_profile_##call);	\
-									\
-	return ret;							\
+	return register_trace_##call(ftrace_profile_##call);		\
 }									\
 									\
-static void ftrace_profile_disable_##call(struct ftrace_event_call *event_call)\
+static void ftrace_profile_disable_##call(void)				\
 {									\
-	if (atomic_add_negative(-1, &event_call->profile_count))	\
-		unregister_trace_##call(ftrace_profile_##call);		\
+	unregister_trace_##call(ftrace_profile_##call);			\
 }
 
 #include TRACE_INCLUDE(TRACE_INCLUDE_FILE)
@@ -660,11 +648,12 @@ __attribute__((section("_ftrace_events"))) event_##call = {		\
  *	struct ftrace_raw_##call *entry;
  *	u64 __addr = 0, __count = 1;
  *	unsigned long irq_flags;
+ *	struct trace_entry *ent;
  *	int __entry_size;
  *	int __data_size;
+ *	int __cpu
  *	int pc;
  *
- *	local_save_flags(irq_flags);
  *	pc = preempt_count();
  *
  *	__data_size = ftrace_get_offsets_<call>(&__data_offsets, args);
@@ -675,25 +664,34 @@ __attribute__((section("_ftrace_events"))) event_##call = {		\
  *			     sizeof(u64));
  *	__entry_size -= sizeof(u32);
  *
- *	do {
- *		char raw_data[__entry_size]; <- allocate our sample in the stack
- *		struct trace_entry *ent;
+ *	// Protect the non nmi buffer
+ *	// This also protects the rcu read side
+ *	local_irq_save(irq_flags);
+ *	__cpu = smp_processor_id();
+ *
+ *	if (in_nmi())
+ *		raw_data = rcu_dereference(trace_profile_buf_nmi);
+ *	else
+ *		raw_data = rcu_dereference(trace_profile_buf);
+ *
+ *	if (!raw_data)
+ *		goto end;
  *
- *		zero dead bytes from alignment to avoid stack leak to userspace:
+ *	raw_data = per_cpu_ptr(raw_data, __cpu);
  *
- *		*(u64 *)(&raw_data[__entry_size - sizeof(u64)]) = 0ULL;
- *		entry = (struct ftrace_raw_<call> *)raw_data;
- *		ent = &entry->ent;
- *		tracing_generic_entry_update(ent, irq_flags, pc);
- *		ent->type = event_call->id;
+ *	//zero dead bytes from alignment to avoid stack leak to userspace:
+ *	*(u64 *)(&raw_data[__entry_size - sizeof(u64)]) = 0ULL;
+ *	entry = (struct ftrace_raw_<call> *)raw_data;
+ *	ent = &entry->ent;
+ *	tracing_generic_entry_update(ent, irq_flags, pc);
+ *	ent->type = event_call->id;
  *
- *		<tstruct> <- do some jobs with dynamic arrays
+ *	<tstruct> <- do some jobs with dynamic arrays
  *
- *		<assign>  <- affect our values
+ *	<assign>  <- affect our values
  *
- *		perf_tpcounter_event(event_call->id, __addr, __count, entry,
- *			     __entry_size);  <- submit them to perf counter
- *	} while (0);
+ *	perf_tpcounter_event(event_call->id, __addr, __count, entry,
+ *		     __entry_size);  <- submit them to perf counter
  *
  * }
  */
@@ -716,11 +714,13 @@ static void ftrace_profile_##call(proto)				\
 	struct ftrace_raw_##call *entry;				\
 	u64 __addr = 0, __count = 1;					\
 	unsigned long irq_flags;					\
+	struct trace_entry *ent;					\
 	int __entry_size;						\
 	int __data_size;						\
+	char *raw_data;							\
+	int __cpu;							\
 	int pc;								\
 									\
-	local_save_flags(irq_flags);					\
 	pc = preempt_count();						\
 									\
 	__data_size = ftrace_get_offsets_##call(&__data_offsets, args); \
@@ -728,23 +728,38 @@ static void ftrace_profile_##call(proto)				\
 			     sizeof(u64));				\
 	__entry_size -= sizeof(u32);					\
 									\
-	do {								\
-		char raw_data[__entry_size];				\
-		struct trace_entry *ent;				\
+	if (WARN_ONCE(__entry_size > FTRACE_MAX_PROFILE_SIZE,		\
+		      "profile buffer not large enough"))		\
+		return;							\
+									\
+	local_irq_save(irq_flags);					\
+	__cpu = smp_processor_id();					\
 									\
-		*(u64 *)(&raw_data[__entry_size - sizeof(u64)]) = 0ULL;	\
-		entry = (struct ftrace_raw_##call *)raw_data;		\
-		ent = &entry->ent;					\
-		tracing_generic_entry_update(ent, irq_flags, pc);	\
-		ent->type = event_call->id;				\
+	if (in_nmi())							\
+		raw_data = rcu_dereference(trace_profile_buf_nmi);		\
+	else								\
+		raw_data = rcu_dereference(trace_profile_buf);		\
 									\
-		tstruct							\
+	if (!raw_data)							\
+		goto end;						\
 									\
-		{ assign; }						\
+	raw_data = per_cpu_ptr(raw_data, __cpu);			\
 									\
-		perf_tpcounter_event(event_call->id, __addr, __count, entry,\
+	*(u64 *)(&raw_data[__entry_size - sizeof(u64)]) = 0ULL;		\
+	entry = (struct ftrace_raw_##call *)raw_data;			\
+	ent = &entry->ent;						\
+	tracing_generic_entry_update(ent, irq_flags, pc);		\
+	ent->type = event_call->id;					\
+									\
+	tstruct								\
+									\
+	{ assign; }							\
+									\
+	perf_tpcounter_event(event_call->id, __addr, __count, entry,	\
 			     __entry_size);				\
-	} while (0);							\
+									\
+end:									\
+	local_irq_restore(irq_flags);					\
 									\
 }
 

init/Kconfig

@@ -1054,13 +1054,6 @@ config PROFILING
 config TRACEPOINTS
 	bool
 
-config MARKERS
-	bool "Activate markers"
-	select TRACEPOINTS
-	help
-	  Place an empty function call at each marker site. Can be
-	  dynamically changed for a probe function.
-
 source "arch/Kconfig"
 
 config SLOW_WORK

kernel/Makefile

@@ -87,7 +87,6 @@ obj-$(CONFIG_RELAY) += relay.o
 obj-$(CONFIG_SYSCTL) += utsname_sysctl.o
 obj-$(CONFIG_TASK_DELAY_ACCT) += delayacct.o
 obj-$(CONFIG_TASKSTATS) += taskstats.o tsacct.o
-obj-$(CONFIG_MARKERS) += marker.o
 obj-$(CONFIG_TRACEPOINTS) += tracepoint.o
 obj-$(CONFIG_LATENCYTOP) += latencytop.o
 obj-$(CONFIG_FUNCTION_TRACER) += trace/

kernel/marker.c

-/*
- * Copyright (C) 2007 Mathieu Desnoyers
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
- */
-#include <linux/module.h>
-#include <linux/mutex.h>
-#include <linux/types.h>
-#include <linux/jhash.h>
-#include <linux/list.h>
-#include <linux/rcupdate.h>
-#include <linux/marker.h>
-#include <linux/err.h>
-#include <linux/slab.h>
-
-extern struct marker __start___markers[];
-extern struct marker __stop___markers[];
-
-/* Set to 1 to enable marker debug output */
-static const int marker_debug;
-
-/*
- * markers_mutex nests inside module_mutex. Markers mutex protects the builtin
- * and module markers and the hash table.
- */
-static DEFINE_MUTEX(markers_mutex);
-
-/*
- * Marker hash table, containing the active markers.
- * Protected by module_mutex.
- */
-#define MARKER_HASH_BITS 6
-#define MARKER_TABLE_SIZE (1 << MARKER_HASH_BITS)
-static struct hlist_head marker_table[MARKER_TABLE_SIZE];
-
-/*
- * Note about RCU :
- * It is used to make sure every handler has finished using its private data
- * between two consecutive operation (add or remove) on a given marker.  It is
- * also used to delay the free of multiple probes array until a quiescent state
- * is reached.
- * marker entries modifications are protected by the markers_mutex.
- */
-struct marker_entry {
-	struct hlist_node hlist;
-	char *format;
-			/* Probe wrapper */
-	void (*call)(const struct marker *mdata, void *call_private, ...);
-	struct marker_probe_closure single;
-	struct marker_probe_closure *multi;
-	int refcount;	/* Number of times armed. 0 if disarmed. */
-	struct rcu_head rcu;
-	void *oldptr;
-	int rcu_pending;
-	unsigned char ptype:1;
-	unsigned char format_allocated:1;
-	char name[0];	/* Contains name'\0'format'\0' */
-};
-
-/**
- * __mark_empty_function - Empty probe callback
- * @probe_private: probe private data
- * @call_private: call site private data
- * @fmt: format string
- * @...: variable argument list
- *
- * Empty callback provided as a probe to the markers. By providing this to a
- * disabled marker, we make sure the  execution flow is always valid even
- * though the function pointer change and the marker enabling are two distinct
- * operations that modifies the execution flow of preemptible code.
- */
-notrace void __mark_empty_function(void *probe_private, void *call_private,
-	const char *fmt, va_list *args)
-{
-}
-EXPORT_SYMBOL_GPL(__mark_empty_function);
-
-/*
- * marker_probe_cb Callback that prepares the variable argument list for probes.
- * @mdata: pointer of type struct marker
- * @call_private: caller site private data
- * @...:  Variable argument list.
- *
- * Since we do not use "typical" pointer based RCU in the 1 argument case, we
- * need to put a full smp_rmb() in this branch. This is why we do not use
- * rcu_dereference() for the pointer read.
- */
-notrace void marker_probe_cb(const struct marker *mdata,
-		void *call_private, ...)
-{
-	va_list args;
-	char ptype;
-
-	/*
-	 * rcu_read_lock_sched does two things : disabling preemption to make
-	 * sure the teardown of the callbacks can be done correctly when they
-	 * are in modules and they insure RCU read coherency.
-	 */
-	rcu_read_lock_sched_notrace();
-	ptype = mdata->ptype;
-	if (likely(!ptype)) {
-		marker_probe_func *func;
-		/* Must read the ptype before ptr. They are not data dependant,
-		 * so we put an explicit smp_rmb() here. */
-		smp_rmb();
-		func = mdata->single.func;
-		/* Must read the ptr before private data. They are not data
-		 * dependant, so we put an explicit smp_rmb() here. */
-		smp_rmb();
-		va_start(args, call_private);
-		func(mdata->single.probe_private, call_private, mdata->format,
-			&args);
-		va_end(args);
-	} else {
-		struct marker_probe_closure *multi;
-		int i;
-		/*
-		 * Read mdata->ptype before mdata->multi.
-		 */
-		smp_rmb();
-		multi = mdata->multi;
-		/*
-		 * multi points to an array, therefore accessing the array
-		 * depends on reading multi. However, even in this case,
-		 * we must insure that the pointer is read _before_ the array
-		 * data. Same as rcu_dereference, but we need a full smp_rmb()
-		 * in the fast path, so put the explicit barrier here.
-		 */
-		smp_read_barrier_depends();
-		for (i = 0; multi[i].func; i++) {
-			va_start(args, call_private);
-			multi[i].func(multi[i].probe_private, call_private,
-				mdata->format, &args);
-			va_end(args);
-		}
-	}
-	rcu_read_unlock_sched_notrace();
-}
-EXPORT_SYMBOL_GPL(marker_probe_cb);
-
-/*
- * marker_probe_cb Callback that does not prepare the variable argument list.
- * @mdata: pointer of type struct marker
- * @call_private: caller site private data
- * @...:  Variable argument list.
- *
- * Should be connected to markers "MARK_NOARGS".
- */
-static notrace void marker_probe_cb_noarg(const struct marker *mdata,
-		void *call_private, ...)
-{
-	va_list args;	/* not initialized */
-	char ptype;
-
-	rcu_read_lock_sched_notrace();
-	ptype = mdata->ptype;
-	if (likely(!ptype)) {
-		marker_probe_func *func;
-		/* Must read the ptype before ptr. They are not data dependant,
-		 * so we put an explicit smp_rmb() here. */
-		smp_rmb();
-		func = mdata->single.func;
-		/* Must read the ptr before private data. They are not data
-		 * dependant, so we put an explicit smp_rmb() here. */
-		smp_rmb();
-		func(mdata->single.probe_private, call_private, mdata->format,
-			&args);
-	} else {
-		struct marker_probe_closure *multi;
-		int i;
-		/*
-		 * Read mdata->ptype before mdata->multi.
-		 */
-		smp_rmb();
-		multi = mdata->multi;
-		/*
-		 * multi points to an array, therefore accessing the array
-		 * depends on reading multi. However, even in this case,
-		 * we must insure that the pointer is read _before_ the array
-		 * data. Same as rcu_dereference, but we need a full smp_rmb()
-		 * in the fast path, so put the explicit barrier here.
-		 */
-		smp_read_barrier_depends();
-		for (i = 0; multi[i].func; i++)
-			multi[i].func(multi[i].probe_private, call_private,
-				mdata->format, &args);
-	}
-	rcu_read_unlock_sched_notrace();
-}
-
-static void free_old_closure(struct rcu_head *head)
-{
-	struct marker_entry *entry = container_of(head,
-		struct marker_entry, rcu);
-	kfree(entry->oldptr);
-	/* Make sure we free the data before setting the pending flag to 0 */
-	smp_wmb();
-	entry->rcu_pending = 0;
-}
-
-static void debug_print_probes(struct marker_entry *entry)
-{
-	int i;
-
-	if (!marker_debug)
-		return;
-
-	if (!entry->ptype) {
-		printk(KERN_DEBUG "Single probe : %p %p\n",
-			entry->single.func,
-			entry->single.probe_private);
-	} else {
-		for (i = 0; entry->multi[i].func; i++)
-			printk(KERN_DEBUG "Multi probe %d : %p %p\n", i,
-				entry->multi[i].func,
-				entry->multi[i].probe_private);
-	}
-}
-
-static struct marker_probe_closure *
-marker_entry_add_probe(struct marker_entry *entry,
-		marker_probe_func *probe, void *probe_private)
-{
-	int nr_probes = 0;
-	struct marker_probe_closure *old, *new;
-
-	WARN_ON(!probe);
-
-	debug_print_probes(entry);
-	old = entry->multi;
-	if (!entry->ptype) {
-		if (entry->single.func == probe &&
-				entry->single.probe_private == probe_private)
-			return ERR_PTR(-EBUSY);
-		if (entry->single.func == __mark_empty_function) {
-			/* 0 -> 1 probes */
-			entry->single.func = probe;
-			entry->single.probe_private = probe_private;
-			entry->refcount = 1;
-			entry->ptype = 0;
-			debug_print_probes(entry);
-			return NULL;
-		} else {
-			/* 1 -> 2 probes */
-			nr_probes = 1;
-			old = NULL;
-		}
-	} else {
-		/* (N -> N+1), (N != 0, 1) probes */
-		for (nr_probes = 0; old[nr_probes].func; nr_probes++)
-			if (old[nr_probes].func == probe
-					&& old[nr_probes].probe_private
-						== probe_private)
-				return ERR_PTR(-EBUSY);
-	}
-	/* + 2 : one for new probe, one for NULL func */
-	new = kzalloc((nr_probes + 2) * sizeof(struct marker_probe_closure),
-			GFP_KERNEL);
-	if (new == NULL)
-		return ERR_PTR(-ENOMEM);
-	if (!old)
-		new[0] = entry->single;
-	else
-		memcpy(new, old,
-			nr_probes * sizeof(struct marker_probe_closure));
-	new[nr_probes].func = probe;
-	new[nr_probes].probe_private = probe_private;
-	entry->refcount = nr_probes + 1;
-	entry->multi = new;
-	entry->ptype = 1;
-	debug_print_probes(entry);
-	return old;
-}
-
-static struct marker_probe_closure *
-marker_entry_remove_probe(struct marker_entry *entry,
-		marker_probe_func *probe, void *probe_private)
-{
-	int nr_probes = 0, nr_del = 0, i;
-	struct marker_probe_closure *old, *new;
-
-	old = entry->multi;
-
-	debug_print_probes(entry);
-	if (!entry->ptype) {
-		/* 0 -> N is an error */
-		WARN_ON(entry->single.func == __mark_empty_function);
-		/* 1 -> 0 probes */
-		WARN_ON(probe && entry->single.func != probe);
-		WARN_ON(entry->single.probe_private != probe_private);
-		entry->single.func = __mark_empty_function;
-		entry->refcount = 0;
-		entry->ptype = 0;
-		debug_print_probes(entry);
-		return NULL;
-	} else {
-		/* (N -> M), (N > 1, M >= 0) probes */
-		for (nr_probes = 0; old[nr_probes].func; nr_probes++) {
-			if ((!probe || old[nr_probes].func == probe)
-					&& old[nr_probes].probe_private
-						== probe_private)
-				nr_del++;
-		}
-	}
-
-	if (nr_probes - nr_del == 0) {
-		/* N -> 0, (N > 1) */
-		entry->single.func = __mark_empty_function;
-		entry->refcount = 0;
-		entry->ptype = 0;
-	} else if (nr_probes - nr_del == 1) {
-		/* N -> 1, (N > 1) */
-		for (i = 0; old[i].func; i++)
-			if ((probe && old[i].func != probe) ||
-					old[i].probe_private != probe_private)
-				entry->single = old[i];
-		entry->refcount = 1;
-		entry->ptype = 0;
-	} else {
-		int j = 0;
-		/* N -> M, (N > 1, M > 1) */
-		/* + 1 for NULL */
-		new = kzalloc((nr_probes - nr_del + 1)
-			* sizeof(struct marker_probe_closure), GFP_KERNEL);
-		if (new == NULL)
-			return ERR_PTR(-ENOMEM);
-		for (i = 0; old[i].func; i++)
-			if ((probe && old[i].func != probe) ||
-					old[i].probe_private != probe_private)
-				new[j++] = old[i];
-		entry->refcount = nr_probes - nr_del;
-		entry->ptype = 1;
-		entry->multi = new;
-	}
-	debug_print_probes(entry);
-	return old;
-}
-
-/*
- * Get marker if the marker is present in the marker hash table.
- * Must be called with markers_mutex held.
- * Returns NULL if not present.
- */
-static struct marker_entry *get_marker(const char *name)
-{
-	struct hlist_head *head;
-	struct hlist_node *node;
-	struct marker_entry *e;
-	u32 hash = jhash(name, strlen(name), 0);
-
-	head = &marker_table[hash & ((1 << MARKER_HASH_BITS)-1)];
-	hlist_for_each_entry(e, node, head, hlist) {
-		if (!strcmp(name, e->name))
-			return e;
-	}
-	return NULL;
-}
-
-/*
- * Add the marker to the marker hash table. Must be called with markers_mutex
- * held.
- */
-static struct marker_entry *add_marker(const char *name, const char *format)
-{
-	struct hlist_head *head;
-	struct hlist_node *node;
-	struct marker_entry *e;
-	size_t name_len = strlen(name) + 1;
-	size_t format_len = 0;
-	u32 hash = jhash(name, name_len-1, 0);
-
-	if (format)
-		format_len = strlen(format) + 1;
-	head = &marker_table[hash & ((1 << MARKER_HASH_BITS)-1)];
-	hlist_for_each_entry(e, node, head, hlist) {
-		if (!strcmp(name, e->name)) {
-			printk(KERN_NOTICE
-				"Marker %s busy\n", name);
-			return ERR_PTR(-EBUSY);	/* Already there */
-		}
-	}
-	/*
-	 * Using kmalloc here to allocate a variable length element. Could
-	 * cause some memory fragmentation if overused.
-	 */
-	e = kmalloc(sizeof(struct marker_entry) + name_len + format_len,
-			GFP_KERNEL);
-	if (!e)
-		return ERR_PTR(-ENOMEM);
-	memcpy(&e->name[0], name, name_len);
-	if (format) {
-		e->format = &e->name[name_len];
-		memcpy(e->format, format, format_len);
-		if (strcmp(e->format, MARK_NOARGS) == 0)
-			e->call = marker_probe_cb_noarg;
-		else
-			e->call = marker_probe_cb;
-		trace_mark(core_marker_format, "name %s format %s",
-				e->name, e->format);
-	} else {
-		e->format = NULL;
-		e->call = marker_probe_cb;
-	}
-	e->single.func = __mark_empty_function;
-	e->single.probe_private = NULL;
-	e->multi = NULL;
-	e->ptype = 0;
-	e->format_allocated = 0;
-	e->refcount = 0;
-	e->rcu_pending = 0;
-	hlist_add_head(&e->hlist, head);
-	return e;
-}
-
-/*
- * Remove the marker from the marker hash table. Must be called with mutex_lock
- * held.
- */
-static int remove_marker(const char *name)
-{
-	struct hlist_head *head;
-	struct hlist_node *node;
-	struct marker_entry *e;
-	int found = 0;
-	size_t len = strlen(name) + 1;
-	u32 hash = jhash(name, len-1, 0);
-
-	head = &marker_table[hash & ((1 << MARKER_HASH_BITS)-1)];
-	hlist_for_each_entry(e, node, head, hlist) {
-		if (!strcmp(name, e->name)) {
-			found = 1;
-			break;
-		}
-	}
-	if (!found)
-		return -ENOENT;
-	if (e->single.func != __mark_empty_function)
-		return -EBUSY;
-	hlist_del(&e->hlist);
-	if (e->format_allocated)
-		kfree(e->format);
-	/* Make sure the call_rcu has been executed */
-	if (e->rcu_pending)
-		rcu_barrier_sched();
-	kfree(e);
-	return 0;
-}
-
-/*
- * Set the mark_entry format to the format found in the element.
- */
-static int marker_set_format(struct marker_entry *entry, const char *format)
-{
-	entry->format = kstrdup(format, GFP_KERNEL);
-	if (!entry->format)
-		return -ENOMEM;
-	entry->format_allocated = 1;
-
-	trace_mark(core_marker_format, "name %s format %s",
-			entry->name, entry->format);
-	return 0;
-}
-
-/*
- * Sets the probe callback corresponding to one marker.
- */
-static int set_marker(struct marker_entry *entry, struct marker *elem,
-		int active)
-{
-	int ret = 0;
-	WARN_ON(strcmp(entry->name, elem->name) != 0);
-
-	if (entry->format) {
-		if (strcmp(entry->format, elem->format) != 0) {
-			printk(KERN_NOTICE
-				"Format mismatch for probe %s "
-				"(%s), marker (%s)\n",
-				entry->name,
-				entry->format,
-				elem->format);
-			return -EPERM;
-		}
-	} else {
-		ret = marker_set_format(entry, elem->format);
-		if (ret)
-			return ret;
-	}
-
-	/*
-	 * probe_cb setup (statically known) is done here. It is
-	 * asynchronous with the rest of execution, therefore we only
-	 * pass from a "safe" callback (with argument) to an "unsafe"
-	 * callback (does not set arguments).
-	 */
-	elem->call = entry->call;
-	/*
-	 * Sanity check :
-	 * We only update the single probe private data when the ptr is
-	 * set to a _non_ single probe! (0 -> 1 and N -> 1, N != 1)
-	 */
-	WARN_ON(elem->single.func != __mark_empty_function
-		&& elem->single.probe_private != entry->single.probe_private
-		&& !elem->ptype);
-	elem->single.probe_private = entry->single.probe_private;
-	/*
-	 * Make sure the private data is valid when we update the
-	 * single probe ptr.
-	 */
-	smp_wmb();
-	elem->single.func = entry->single.func;
-	/*
-	 * We also make sure that the new probe callbacks array is consistent
-	 * before setting a pointer to it.
-	 */
-	rcu_assign_pointer(elem->multi, entry->multi);
-	/*
-	 * Update the function or multi probe array pointer before setting the
-	 * ptype.
-	 */
-	smp_wmb();
-	elem->ptype = entry->ptype;
-
-	if (elem->tp_name && (active ^ elem->state)) {
-		WARN_ON(!elem->tp_cb);
-		/*
-		 * It is ok to directly call the probe registration because type
-		 * checking has been done in the __trace_mark_tp() macro.
-		 */
-
-		if (active) {
-			/*
-			 * try_module_get should always succeed because we hold
-			 * lock_module() to get the tp_cb address.
-			 */
-			ret = try_module_get(__module_text_address(
-				(unsigned long)elem->tp_cb));
-			BUG_ON(!ret);
-			ret = tracepoint_probe_register_noupdate(
-				elem->tp_name,
-				elem->tp_cb);
-		} else {
-			ret = tracepoint_probe_unregister_noupdate(
-				elem->tp_name,
-				elem->tp_cb);
-			/*
-			 * tracepoint_probe_update_all() must be called
-			 * before the module containing tp_cb is unloaded.
-			 */
-			module_put(__module_text_address(
-				(unsigned long)elem->tp_cb));
-		}
-	}
-	elem->state = active;
-
-	return ret;
-}
-
-/*
- * Disable a marker and its probe callback.
- * Note: only waiting an RCU period after setting elem->call to the empty
- * function insures that the original callback is not used anymore. This insured
- * by rcu_read_lock_sched around the call site.
- */
-static void disable_marker(struct marker *elem)
-{
-	int ret;
-
-	/* leave "call" as is. It is known statically. */
-	if (elem->tp_name && elem->state) {
-		WARN_ON(!elem->tp_cb);
-		/*
-		 * It is ok to directly call the probe registration because type
-		 * checking has been done in the __trace_mark_tp() macro.
-		 */
-		ret = tracepoint_probe_unregister_noupdate(elem->tp_name,
-			elem->tp_cb);
-		WARN_ON(ret);
-		/*
-		 * tracepoint_probe_update_all() must be called
-		 * before the module containing tp_cb is unloaded.
-		 */
-		module_put(__module_text_address((unsigned long)elem->tp_cb));
-	}
-	elem->state = 0;
-	elem->single.func = __mark_empty_function;
-	/* Update the function before setting the ptype */
-	smp_wmb();
-	elem->ptype = 0;	/* single probe */
-	/*
-	 * Leave the private data and id there, because removal is racy and
-	 * should be done only after an RCU period. These are never used until
-	 * the next initialization anyway.
-	 */
-}
-
-/**
- * marker_update_probe_range - Update a probe range
- * @begin: beginning of the range
- * @end: end of the range
- *
- * Updates the probe callback corresponding to a range of markers.
- */
-void marker_update_probe_range(struct marker *begin,
-	struct marker *end)
-{
-	struct marker *iter;
-	struct marker_entry *mark_entry;
-
-	mutex_lock(&markers_mutex);
-	for (iter = begin; iter < end; iter++) {
-		mark_entry = get_marker(iter->name);
-		if (mark_entry) {
-			set_marker(mark_entry, iter, !!mark_entry->refcount);
-			/*
-			 * ignore error, continue
-			 */
-		} else {
-			disable_marker(iter);
-		}
-	}
-	mutex_unlock(&markers_mutex);
-}
-
-/*
- * Update probes, removing the faulty probes.
- *
- * Internal callback only changed before the first probe is connected to it.
- * Single probe private data can only be changed on 0 -> 1 and 2 -> 1
- * transitions.  All other transitions will leave the old private data valid.
- * This makes the non-atomicity of the callback/private data updates valid.
- *
- * "special case" updates :
- * 0 -> 1 callback
- * 1 -> 0 callback
- * 1 -> 2 callbacks
- * 2 -> 1 callbacks
- * Other updates all behave the same, just like the 2 -> 3 or 3 -> 2 updates.
- * Site effect : marker_set_format may delete the marker entry (creating a
- * replacement).
- */
-static void marker_update_probes(void)
-{
-	/* Core kernel markers */
-	marker_update_probe_range(__start___markers, __stop___markers);
-	/* Markers in modules. */
-	module_update_markers();
-	tracepoint_probe_update_all();
-}
-
-/**
- * marker_probe_register -  Connect a probe to a marker
- * @name: marker name
- * @format: format string
- * @probe: probe handler
- * @probe_private: probe private data
- *
- * private data must be a valid allocated memory address, or NULL.
- * Returns 0 if ok, error value on error.
- * The probe address must at least be aligned on the architecture pointer size.
- */
-int marker_probe_register(const char *name, const char *format,
-			marker_probe_func *probe, void *probe_private)
-{
-	struct marker_entry *entry;
-	int ret = 0;
-	struct marker_probe_closure *old;
-
-	mutex_lock(&markers_mutex);
-	entry = get_marker(name);
-	if (!entry) {
-		entry = add_marker(name, format);
-		if (IS_ERR(entry))
-			ret = PTR_ERR(entry);
-	} else if (format) {
-		if (!entry->format)
-			ret = marker_set_format(entry, format);
-		else if (strcmp(entry->format, format))
-			ret = -EPERM;
-	}
-	if (ret)
-		goto end;
-
-	/*
-	 * If we detect that a call_rcu is pending for this marker,
-	 * make sure it's executed now.
-	 */
-	if (entry->rcu_pending)
-		rcu_barrier_sched();
-	old = marker_entry_add_probe(entry, probe, probe_private);
-	if (IS_ERR(old)) {
-		ret = PTR_ERR(old);
-		goto end;
-	}
-	mutex_unlock(&markers_mutex);
-	marker_update_probes();
-	mutex_lock(&markers_mutex);
-	entry = get_marker(name);
-	if (!entry)
-		goto end;
-	if (entry->rcu_pending)
-		rcu_barrier_sched();
-	entry->oldptr = old;
-	entry->rcu_pending = 1;
-	/* write rcu_pending before calling the RCU callback */
-	smp_wmb();
-	call_rcu_sched(&entry->rcu, free_old_closure);
-end:
-	mutex_unlock(&markers_mutex);
-	return ret;
-}
-EXPORT_SYMBOL_GPL(marker_probe_register);
-
-/**
- * marker_probe_unregister -  Disconnect a probe from a marker
- * @name: marker name
- * @probe: probe function pointer
- * @probe_private: probe private data
- *
- * Returns the private data given to marker_probe_register, or an ERR_PTR().
- * We do not need to call a synchronize_sched to make sure the probes have
- * finished running before doing a module unload, because the module unload
- * itself uses stop_machine(), which insures that every preempt disabled section
- * have finished.
- */
-int marker_probe_unregister(const char *name,
-	marker_probe_func *probe, void *probe_private)
-{
-	struct marker_entry *entry;
-	struct marker_probe_closure *old;
-	int ret = -ENOENT;
-
-	mutex_lock(&markers_mutex);
-	entry = get_marker(name);
-	if (!entry)
-		goto end;
-	if (entry->rcu_pending)
-		rcu_barrier_sched();
-	old = marker_entry_remove_probe(entry, probe, probe_private);
-	mutex_unlock(&markers_mutex);
-	marker_update_probes();
-	mutex_lock(&markers_mutex);
-	entry = get_marker(name);
-	if (!entry)
-		goto end;
-	if (entry->rcu_pending)
-		rcu_barrier_sched();
-	entry->oldptr = old;
-	entry->rcu_pending = 1;
-	/* write rcu_pending before calling the RCU callback */
-	smp_wmb();
-	call_rcu_sched(&entry->rcu, free_old_closure);
-	remove_marker(name);	/* Ignore busy error message */
-	ret = 0;
-end:
-	mutex_unlock(&markers_mutex);
-	return ret;
-}
-EXPORT_SYMBOL_GPL(marker_probe_unregister);
-
-static struct marker_entry *
-get_marker_from_private_data(marker_probe_func *probe, void *probe_private)
-{
-	struct marker_entry *entry;
-	unsigned int i;
-	struct hlist_head *head;
-	struct hlist_node *node;
-
-	for (i = 0; i < MARKER_TABLE_SIZE; i++) {
-		head = &marker_table[i];
-		hlist_for_each_entry(entry, node, head, hlist) {
-			if (!entry->ptype) {
-				if (entry->single.func == probe
-						&& entry->single.probe_private
-						== probe_private)
-					return entry;
-			} else {
-				struct marker_probe_closure *closure;
-				closure = entry->multi;
-				for (i = 0; closure[i].func; i++) {
-					if (closure[i].func == probe &&
-							closure[i].probe_private
-							== probe_private)
-						return entry;
-				}
-			}
-		}
-	}
-	return NULL;
-}
-
-/**
- * marker_probe_unregister_private_data -  Disconnect a probe from a marker
- * @probe: probe function
- * @probe_private: probe private data
- *
- * Unregister a probe by providing the registered private data.
- * Only removes the first marker found in hash table.
- * Return 0 on success or error value.
- * We do not need to call a synchronize_sched to make sure the probes have
- * finished running before doing a module unload, because the module unload
- * itself uses stop_machine(), which insures that every preempt disabled section
- * have finished.
- */
-int marker_probe_unregister_private_data(marker_probe_func *probe,
-		void *probe_private)
-{
-	struct marker_entry *entry;
-	int ret = 0;
-	struct marker_probe_closure *old;
-
-	mutex_lock(&markers_mutex);
-	entry = get_marker_from_private_data(probe, probe_private);
-	if (!entry) {
-		ret = -ENOENT;
-		goto end;
-	}
-	if (entry->rcu_pending)
-		rcu_barrier_sched();
-	old = marker_entry_remove_probe(entry, NULL, probe_private);
-	mutex_unlock(&markers_mutex);
-	marker_update_probes();
-	mutex_lock(&markers_mutex);
-	entry = get_marker_from_private_data(probe, probe_private);
-	if (!entry)
-		goto end;
-	if (entry->rcu_pending)
-		rcu_barrier_sched();
-	entry->oldptr = old;
-	entry->rcu_pending = 1;
-	/* write rcu_pending before calling the RCU callback */
-	smp_wmb();
-	call_rcu_sched(&entry->rcu, free_old_closure);
-	remove_marker(entry->name);	/* Ignore busy error message */
-end:
-	mutex_unlock(&markers_mutex);
-	return ret;
-}
-EXPORT_SYMBOL_GPL(marker_probe_unregister_private_data);
-
-/**
- * marker_get_private_data - Get a marker's probe private data
- * @name: marker name
- * @probe: probe to match
- * @num: get the nth matching probe's private data
- *
- * Returns the nth private data pointer (starting from 0) matching, or an
- * ERR_PTR.
- * Returns the private data pointer, or an ERR_PTR.
- * The private data pointer should _only_ be dereferenced if the caller is the
- * owner of the data, or its content could vanish. This is mostly used to
- * confirm that a caller is the owner of a registered probe.
- */
-void *marker_get_private_data(const char *name, marker_probe_func *probe,
-		int num)
-{
-	struct hlist_head *head;
-	struct hlist_node *node;
-	struct marker_entry *e;
-	size_t name_len = strlen(name) + 1;
-	u32 hash = jhash(name, name_len-1, 0);
-	int i;
-
-	head = &marker_table[hash & ((1 << MARKER_HASH_BITS)-1)];
-	hlist_for_each_entry(e, node, head, hlist) {
-		if (!strcmp(name, e->name)) {
-			if (!e->ptype) {
-				if (num == 0 && e->single.func == probe)
-					return e->single.probe_private;
-			} else {
-				struct marker_probe_closure *closure;
-				int match = 0;
-				closure = e->multi;
-				for (i = 0; closure[i].func; i++) {
-					if (closure[i].func != probe)
-						continue;
-					if (match++ == num)
-						return closure[i].probe_private;
-				}
-			}
-			break;
-		}
-	}
-	return ERR_PTR(-ENOENT);
-}
-EXPORT_SYMBOL_GPL(marker_get_private_data);
-
-#ifdef CONFIG_MODULES
-
-int marker_module_notify(struct notifier_block *self,
-			 unsigned long val, void *data)
-{
-	struct module *mod = data;
-
-	switch (val) {
-	case MODULE_STATE_COMING:
-		marker_update_probe_range(mod->markers,
-			mod->markers + mod->num_markers);
-		break;
-	case MODULE_STATE_GOING:
-		marker_update_probe_range(mod->markers,
-			mod->markers + mod->num_markers);
-		break;
-	}
-	return 0;
-}
-
-struct notifier_block marker_module_nb = {
-	.notifier_call = marker_module_notify,
-	.priority = 0,
-};
-
-static int init_markers(void)
-{
-	return register_module_notifier(&marker_module_nb);
-}
-__initcall(init_markers);
-
-#endif /* CONFIG_MODULES */

kernel/module.c

@@ -2237,10 +2237,6 @@ static noinline struct module *load_module(void __user *umod,
 				  sizeof(*mod->ctors), &mod->num_ctors);
 #endif
 
-#ifdef CONFIG_MARKERS
-	mod->markers = section_objs(hdr, sechdrs, secstrings, "__markers",
-				    sizeof(*mod->markers), &mod->num_markers);
-#endif
 #ifdef CONFIG_TRACEPOINTS
 	mod->tracepoints = section_objs(hdr, sechdrs, secstrings,
 					"__tracepoints",
@@ -2958,20 +2954,6 @@ void module_layout(struct module *mod,
 EXPORT_SYMBOL(module_layout);
 #endif
 
-#ifdef CONFIG_MARKERS
-void module_update_markers(void)
-{
-	struct module *mod;
-
-	mutex_lock(&module_mutex);
-	list_for_each_entry(mod, &modules, list)
-		if (!mod->taints)
-			marker_update_probe_range(mod->markers,
-				mod->markers + mod->num_markers);
-	mutex_unlock(&module_mutex);
-}
-#endif
-
 #ifdef CONFIG_TRACEPOINTS
 void module_update_tracepoints(void)
 {

kernel/profile.c

@@ -442,48 +442,51 @@ void profile_tick(int type)
 
 #ifdef CONFIG_PROC_FS
 #include <linux/proc_fs.h>
+#include <linux/seq_file.h>
 #include <asm/uaccess.h>
 
-static int prof_cpu_mask_read_proc(char *page, char **start, off_t off,
-			int count, int *eof, void *data)
+static int prof_cpu_mask_proc_show(struct seq_file *m, void *v)
 {
-	int len = cpumask_scnprintf(page, count, data);
-	if (count - len < 2)
-		return -EINVAL;
-	len += sprintf(page + len, "\n");
-	return len;
+	seq_cpumask(m, prof_cpu_mask);
+	seq_putc(m, '\n');
+	return 0;
 }
 
-static int prof_cpu_mask_write_proc(struct file *file,
-	const char __user *buffer,  unsigned long count, void *data)
+static int prof_cpu_mask_proc_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, prof_cpu_mask_proc_show, NULL);
+}
+
+static ssize_t prof_cpu_mask_proc_write(struct file *file,
+	const char __user *buffer, size_t count, loff_t *pos)
 {
-	struct cpumask *mask = data;
-	unsigned long full_count = count, err;
 	cpumask_var_t new_value;
+	int err;
 
 	if (!alloc_cpumask_var(&new_value, GFP_KERNEL))
 		return -ENOMEM;
 
 	err = cpumask_parse_user(buffer, count, new_value);
 	if (!err) {
-		cpumask_copy(mask, new_value);
-		err = full_count;
+		cpumask_copy(prof_cpu_mask, new_value);
+		err = count;
 	}
 	free_cpumask_var(new_value);
 	return err;
 }
 
+static const struct file_operations prof_cpu_mask_proc_fops = {
+	.open		= prof_cpu_mask_proc_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= single_release,
+	.write		= prof_cpu_mask_proc_write,
+};
+
 void create_prof_cpu_mask(struct proc_dir_entry *root_irq_dir)
 {
-	struct proc_dir_entry *entry;
-
 	/* create /proc/irq/prof_cpu_mask */
-	entry = create_proc_entry("prof_cpu_mask", 0600, root_irq_dir);
-	if (!entry)
-		return;
-	entry->data = prof_cpu_mask;
-	entry->read_proc = prof_cpu_mask_read_proc;
-	entry->write_proc = prof_cpu_mask_write_proc;
+	proc_create("prof_cpu_mask", 0600, root_irq_dir, &prof_cpu_mask_proc_fops);
 }
 
 /*

kernel/trace/ftrace.c

@@ -2414,11 +2414,9 @@ unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
 static void *
 __g_next(struct seq_file *m, loff_t *pos)
 {
-	unsigned long *array = m->private;
-
 	if (*pos >= ftrace_graph_count)
 		return NULL;
-	return &array[*pos];
+	return &ftrace_graph_funcs[*pos];
 }
 
 static void *
@@ -2482,16 +2480,10 @@ ftrace_graph_open(struct inode *inode, struct file *file)
 		ftrace_graph_count = 0;
 		memset(ftrace_graph_funcs, 0, sizeof(ftrace_graph_funcs));
 	}
+	mutex_unlock(&graph_lock);
 
-	if (file->f_mode & FMODE_READ) {
+	if (file->f_mode & FMODE_READ)
 		ret = seq_open(file, &ftrace_graph_seq_ops);
-		if (!ret) {
-			struct seq_file *m = file->private_data;
-			m->private = ftrace_graph_funcs;
-		}
-	} else
-		file->private_data = ftrace_graph_funcs;
-	mutex_unlock(&graph_lock);
 
 	return ret;
 }
@@ -2560,7 +2552,6 @@ ftrace_graph_write(struct file *file, const char __user *ubuf,
 		   size_t cnt, loff_t *ppos)
 {
 	struct trace_parser parser;
-	unsigned long *array;
 	size_t read = 0;
 	ssize_t ret;
 
@@ -2574,12 +2565,6 @@ ftrace_graph_write(struct file *file, const char __user *ubuf,
 		goto out;
 	}
 
-	if (file->f_mode & FMODE_READ) {
-		struct seq_file *m = file->private_data;
-		array = m->private;
-	} else
-		array = file->private_data;
-
 	if (trace_parser_get_init(&parser, FTRACE_BUFF_MAX)) {
 		ret = -ENOMEM;
 		goto out;
@@ -2591,7 +2576,7 @@ ftrace_graph_write(struct file *file, const char __user *ubuf,
 		parser.buffer[parser.idx] = 0;
 
 		/* we allow only one expression at a time */
-		ret = ftrace_set_func(array, &ftrace_graph_count,
+		ret = ftrace_set_func(ftrace_graph_funcs, &ftrace_graph_count,
 					parser.buffer);
 		if (ret)
 			goto out;

kernel/trace/trace.c

@@ -125,13 +125,13 @@ int ftrace_dump_on_oops;
 
 static int tracing_set_tracer(const char *buf);
 
-#define BOOTUP_TRACER_SIZE		100
-static char bootup_tracer_buf[BOOTUP_TRACER_SIZE] __initdata;
+#define MAX_TRACER_SIZE		100
+static char bootup_tracer_buf[MAX_TRACER_SIZE] __initdata;
 static char *default_bootup_tracer;
 
 static int __init set_ftrace(char *str)
 {
-	strncpy(bootup_tracer_buf, str, BOOTUP_TRACER_SIZE);
+	strncpy(bootup_tracer_buf, str, MAX_TRACER_SIZE);
 	default_bootup_tracer = bootup_tracer_buf;
 	/* We are using ftrace early, expand it */
 	ring_buffer_expanded = 1;
@@ -241,13 +241,6 @@ static struct tracer		*trace_types __read_mostly;
 /* current_trace points to the tracer that is currently active */
 static struct tracer		*current_trace __read_mostly;
 
-/*
- * max_tracer_type_len is used to simplify the allocating of
- * buffers to read userspace tracer names. We keep track of
- * the longest tracer name registered.
- */
-static int			max_tracer_type_len;
-
 /*
  * trace_types_lock is used to protect the trace_types list.
  * This lock is also used to keep user access serialized.
@@ -619,7 +612,6 @@ __releases(kernel_lock)
 __acquires(kernel_lock)
 {
 	struct tracer *t;
-	int len;
 	int ret = 0;
 
 	if (!type->name) {
@@ -627,6 +619,11 @@ __acquires(kernel_lock)
 		return -1;
 	}
 
+	if (strlen(type->name) > MAX_TRACER_SIZE) {
+		pr_info("Tracer has a name longer than %d\n", MAX_TRACER_SIZE);
+		return -1;
+	}
+
 	/*
 	 * When this gets called we hold the BKL which means that
 	 * preemption is disabled. Various trace selftests however
@@ -641,7 +638,7 @@ __acquires(kernel_lock)
 	for (t = trace_types; t; t = t->next) {
 		if (strcmp(type->name, t->name) == 0) {
 			/* already found */
-			pr_info("Trace %s already registered\n",
+			pr_info("Tracer %s already registered\n",
 				type->name);
 			ret = -1;
 			goto out;
@@ -692,9 +689,6 @@ __acquires(kernel_lock)
 
 	type->next = trace_types;
 	trace_types = type;
-	len = strlen(type->name);
-	if (len > max_tracer_type_len)
-		max_tracer_type_len = len;
 
  out:
 	tracing_selftest_running = false;
@@ -703,7 +697,7 @@ __acquires(kernel_lock)
 	if (ret || !default_bootup_tracer)
 		goto out_unlock;
 
-	if (strncmp(default_bootup_tracer, type->name, BOOTUP_TRACER_SIZE))
+	if (strncmp(default_bootup_tracer, type->name, MAX_TRACER_SIZE))
 		goto out_unlock;
 
 	printk(KERN_INFO "Starting tracer '%s'\n", type->name);
@@ -725,14 +719,13 @@ __acquires(kernel_lock)
 void unregister_tracer(struct tracer *type)
 {
 	struct tracer **t;
-	int len;
 
 	mutex_lock(&trace_types_lock);
 	for (t = &trace_types; *t; t = &(*t)->next) {
 		if (*t == type)
 			goto found;
 	}
-	pr_info("Trace %s not registered\n", type->name);
+	pr_info("Tracer %s not registered\n", type->name);
 	goto out;
 
  found:
@@ -745,17 +738,7 @@ void unregister_tracer(struct tracer *type)
 			current_trace->stop(&global_trace);
 		current_trace = &nop_trace;
 	}
-
-	if (strlen(type->name) != max_tracer_type_len)
-		goto out;
-
-	max_tracer_type_len = 0;
-	for (t = &trace_types; *t; t = &(*t)->next) {
-		len = strlen((*t)->name);
-		if (len > max_tracer_type_len)
-			max_tracer_type_len = len;
-	}
- out:
+out:
 	mutex_unlock(&trace_types_lock);
 }
 
@@ -2604,7 +2587,7 @@ static ssize_t
 tracing_set_trace_read(struct file *filp, char __user *ubuf,
 		       size_t cnt, loff_t *ppos)
 {
-	char buf[max_tracer_type_len+2];
+	char buf[MAX_TRACER_SIZE+2];
 	int r;
 
 	mutex_lock(&trace_types_lock);
@@ -2754,15 +2737,15 @@ static ssize_t
 tracing_set_trace_write(struct file *filp, const char __user *ubuf,
 			size_t cnt, loff_t *ppos)
 {
-	char buf[max_tracer_type_len+1];
+	char buf[MAX_TRACER_SIZE+1];
 	int i;
 	size_t ret;
 	int err;
 
 	ret = cnt;
 
-	if (cnt > max_tracer_type_len)
-		cnt = max_tracer_type_len;
+	if (cnt > MAX_TRACER_SIZE)
+		cnt = MAX_TRACER_SIZE;
 
 	if (copy_from_user(&buf, ubuf, cnt))
 		return -EFAULT;

kernel/trace/trace_event_profile.c

@@ -8,6 +8,57 @@
 #include <linux/module.h>
 #include "trace.h"
 
+/*
+ * We can't use a size but a type in alloc_percpu()
+ * So let's create a dummy type that matches the desired size
+ */
+typedef struct {char buf[FTRACE_MAX_PROFILE_SIZE];} profile_buf_t;
+
+char		*trace_profile_buf;
+EXPORT_SYMBOL_GPL(trace_profile_buf);
+
+char		*trace_profile_buf_nmi;
+EXPORT_SYMBOL_GPL(trace_profile_buf_nmi);
+
+/* Count the events in use (per event id, not per instance) */
+static int	total_profile_count;
+
+static int ftrace_profile_enable_event(struct ftrace_event_call *event)
+{
+	char *buf;
+	int ret = -ENOMEM;
+
+	if (atomic_inc_return(&event->profile_count))
+		return 0;
+
+	if (!total_profile_count++) {
+		buf = (char *)alloc_percpu(profile_buf_t);
+		if (!buf)
+			goto fail_buf;
+
+		rcu_assign_pointer(trace_profile_buf, buf);
+
+		buf = (char *)alloc_percpu(profile_buf_t);
+		if (!buf)
+			goto fail_buf_nmi;
+
+		rcu_assign_pointer(trace_profile_buf_nmi, buf);
+	}
+
+	ret = event->profile_enable();
+	if (!ret)
+		return 0;
+
+	kfree(trace_profile_buf_nmi);
+fail_buf_nmi:
+	kfree(trace_profile_buf);
+fail_buf:
+	total_profile_count--;
+	atomic_dec(&event->profile_count);
+
+	return ret;
+}
+
 int ftrace_profile_enable(int event_id)
 {
 	struct ftrace_event_call *event;
@@ -17,7 +68,7 @@ int ftrace_profile_enable(int event_id)
 	list_for_each_entry(event, &ftrace_events, list) {
 		if (event->id == event_id && event->profile_enable &&
 		    try_module_get(event->mod)) {
-			ret = event->profile_enable(event);
+			ret = ftrace_profile_enable_event(event);
 			break;
 		}
 	}
@@ -26,6 +77,33 @@ int ftrace_profile_enable(int event_id)
 	return ret;
 }
 
+static void ftrace_profile_disable_event(struct ftrace_event_call *event)
+{
+	char *buf, *nmi_buf;
+
+	if (!atomic_add_negative(-1, &event->profile_count))
+		return;
+
+	event->profile_disable();
+
+	if (!--total_profile_count) {
+		buf = trace_profile_buf;
+		rcu_assign_pointer(trace_profile_buf, NULL);
+
+		nmi_buf = trace_profile_buf_nmi;
+		rcu_assign_pointer(trace_profile_buf_nmi, NULL);
+
+		/*
+		 * Ensure every events in profiling have finished before
+		 * releasing the buffers
+		 */
+		synchronize_sched();
+
+		free_percpu(buf);
+		free_percpu(nmi_buf);
+	}
+}
+
 void ftrace_profile_disable(int event_id)
 {
 	struct ftrace_event_call *event;
@@ -33,7 +111,7 @@ void ftrace_profile_disable(int event_id)
 	mutex_lock(&event_mutex);
 	list_for_each_entry(event, &ftrace_events, list) {
 		if (event->id == event_id) {
-			event->profile_disable(event);
+			ftrace_profile_disable_event(event);
 			module_put(event->mod);
 			break;
 		}

kernel/trace/trace_events.c

@@ -271,42 +271,32 @@ ftrace_event_write(struct file *file, const char __user *ubuf,
 static void *
 t_next(struct seq_file *m, void *v, loff_t *pos)
 {
-	struct list_head *list = m->private;
-	struct ftrace_event_call *call;
+	struct ftrace_event_call *call = v;
 
 	(*pos)++;
 
-	for (;;) {
-		if (list == &ftrace_events)
-			return NULL;
-
-		call = list_entry(list, struct ftrace_event_call, list);
-
+	list_for_each_entry_continue(call, &ftrace_events, list) {
 		/*
 		 * The ftrace subsystem is for showing formats only.
 		 * They can not be enabled or disabled via the event files.
 		 */
 		if (call->regfunc)
-			break;
-
-		list = list->next;
+			return call;
 	}
 
-	m->private = list->next;
-
-	return call;
+	return NULL;
 }
 
 static void *t_start(struct seq_file *m, loff_t *pos)
 {
-	struct ftrace_event_call *call = NULL;
+	struct ftrace_event_call *call;
 	loff_t l;
 
 	mutex_lock(&event_mutex);
 
-	m->private = ftrace_events.next;
+	call = list_entry(&ftrace_events, struct ftrace_event_call, list);
 	for (l = 0; l <= *pos; ) {
-		call = t_next(m, NULL, &l);
+		call = t_next(m, call, &l);
 		if (!call)
 			break;
 	}
@@ -316,37 +306,28 @@ static void *t_start(struct seq_file *m, loff_t *pos)
 static void *
 s_next(struct seq_file *m, void *v, loff_t *pos)
 {
-	struct list_head *list = m->private;
-	struct ftrace_event_call *call;
+	struct ftrace_event_call *call = v;
 
 	(*pos)++;
 
- retry:
-	if (list == &ftrace_events)
-		return NULL;
-
-	call = list_entry(list, struct ftrace_event_call, list);
-
-	if (!call->enabled) {
-		list = list->next;
-		goto retry;
+	list_for_each_entry_continue(call, &ftrace_events, list) {
+		if (call->enabled)
+			return call;
 	}
 
-	m->private = list->next;
-
-	return call;
+	return NULL;
 }
 
 static void *s_start(struct seq_file *m, loff_t *pos)
 {
-	struct ftrace_event_call *call = NULL;
+	struct ftrace_event_call *call;
 	loff_t l;
 
 	mutex_lock(&event_mutex);
 
-	m->private = ftrace_events.next;
+	call = list_entry(&ftrace_events, struct ftrace_event_call, list);
 	for (l = 0; l <= *pos; ) {
-		call = s_next(m, NULL, &l);
+		call = s_next(m, call, &l);
 		if (!call)
 			break;
 	}

kernel/trace/trace_printk.c

@@ -11,7 +11,6 @@
 #include <linux/ftrace.h>
 #include <linux/string.h>
 #include <linux/module.h>
-#include <linux/marker.h>
 #include <linux/mutex.h>
 #include <linux/ctype.h>
 #include <linux/list.h>

kernel/trace/trace_syscalls.c

@@ -384,10 +384,13 @@ static int sys_prof_refcount_exit;
 
 static void prof_syscall_enter(struct pt_regs *regs, long id)
 {
-	struct syscall_trace_enter *rec;
 	struct syscall_metadata *sys_data;
+	struct syscall_trace_enter *rec;
+	unsigned long flags;
+	char *raw_data;
 	int syscall_nr;
 	int size;
+	int cpu;
 
 	syscall_nr = syscall_get_nr(current, regs);
 	if (!test_bit(syscall_nr, enabled_prof_enter_syscalls))
@@ -402,20 +405,38 @@ static void prof_syscall_enter(struct pt_regs *regs, long id)
 	size = ALIGN(size + sizeof(u32), sizeof(u64));
 	size -= sizeof(u32);
 
-	do {
-		char raw_data[size];
+	if (WARN_ONCE(size > FTRACE_MAX_PROFILE_SIZE,
+		      "profile buffer not large enough"))
+		return;
+
+	/* Protect the per cpu buffer, begin the rcu read side */
+	local_irq_save(flags);
 
-		/* zero the dead bytes from align to not leak stack to user */
-		*(u64 *)(&raw_data[size - sizeof(u64)]) = 0ULL;
+	cpu = smp_processor_id();
+
+	if (in_nmi())
+		raw_data = rcu_dereference(trace_profile_buf_nmi);
+	else
+		raw_data = rcu_dereference(trace_profile_buf);
+
+	if (!raw_data)
+		goto end;
 
-		rec = (struct syscall_trace_enter *) raw_data;
-		tracing_generic_entry_update(&rec->ent, 0, 0);
-		rec->ent.type = sys_data->enter_id;
-		rec->nr = syscall_nr;
-		syscall_get_arguments(current, regs, 0, sys_data->nb_args,
-				       (unsigned long *)&rec->args);
-		perf_tpcounter_event(sys_data->enter_id, 0, 1, rec, size);
-	} while(0);
+	raw_data = per_cpu_ptr(raw_data, cpu);
+
+	/* zero the dead bytes from align to not leak stack to user */
+	*(u64 *)(&raw_data[size - sizeof(u64)]) = 0ULL;
+
+	rec = (struct syscall_trace_enter *) raw_data;
+	tracing_generic_entry_update(&rec->ent, 0, 0);
+	rec->ent.type = sys_data->enter_id;
+	rec->nr = syscall_nr;
+	syscall_get_arguments(current, regs, 0, sys_data->nb_args,
+			       (unsigned long *)&rec->args);
+	perf_tpcounter_event(sys_data->enter_id, 0, 1, rec, size);
+
+end:
+	local_irq_restore(flags);
 }
 
 int reg_prof_syscall_enter(char *name)
@@ -460,8 +481,12 @@ void unreg_prof_syscall_enter(char *name)
 static void prof_syscall_exit(struct pt_regs *regs, long ret)
 {
 	struct syscall_metadata *sys_data;
-	struct syscall_trace_exit rec;
+	struct syscall_trace_exit *rec;
+	unsigned long flags;
 	int syscall_nr;
+	char *raw_data;
+	int size;
+	int cpu;
 
 	syscall_nr = syscall_get_nr(current, regs);
 	if (!test_bit(syscall_nr, enabled_prof_exit_syscalls))
@@ -471,12 +496,46 @@ static void prof_syscall_exit(struct pt_regs *regs, long ret)
 	if (!sys_data)
 		return;
 
-	tracing_generic_entry_update(&rec.ent, 0, 0);
-	rec.ent.type = sys_data->exit_id;
-	rec.nr = syscall_nr;
-	rec.ret = syscall_get_return_value(current, regs);
+	/* We can probably do that at build time */
+	size = ALIGN(sizeof(*rec) + sizeof(u32), sizeof(u64));
+	size -= sizeof(u32);
 
-	perf_tpcounter_event(sys_data->exit_id, 0, 1, &rec, sizeof(rec));
+	/*
+	 * Impossible, but be paranoid with the future
+	 * How to put this check outside runtime?
+	 */
+	if (WARN_ONCE(size > FTRACE_MAX_PROFILE_SIZE,
+		"exit event has grown above profile buffer size"))
+		return;
+
+	/* Protect the per cpu buffer, begin the rcu read side */
+	local_irq_save(flags);
+	cpu = smp_processor_id();
+
+	if (in_nmi())
+		raw_data = rcu_dereference(trace_profile_buf_nmi);
+	else
+		raw_data = rcu_dereference(trace_profile_buf);
+
+	if (!raw_data)
+		goto end;
+
+	raw_data = per_cpu_ptr(raw_data, cpu);
+
+	/* zero the dead bytes from align to not leak stack to user */
+	*(u64 *)(&raw_data[size - sizeof(u64)]) = 0ULL;
+
+	rec = (struct syscall_trace_exit *)raw_data;
+
+	tracing_generic_entry_update(&rec->ent, 0, 0);
+	rec->ent.type = sys_data->exit_id;
+	rec->nr = syscall_nr;
+	rec->ret = syscall_get_return_value(current, regs);
+
+	perf_tpcounter_event(sys_data->exit_id, 0, 1, rec, size);
+
+end:
+	local_irq_restore(flags);
 }
 
 int reg_prof_syscall_exit(char *name)

samples/Kconfig

@@ -7,12 +7,6 @@ menuconfig SAMPLES
 
 if SAMPLES
 
-config SAMPLE_MARKERS
-	tristate "Build markers examples -- loadable modules only"
-	depends on MARKERS && m
-	help
-	  This build markers example modules.
-
 config SAMPLE_TRACEPOINTS
 	tristate "Build tracepoints examples -- loadable modules only"
 	depends on TRACEPOINTS && m

samples/Makefile

 # Makefile for Linux samples code
 
-obj-$(CONFIG_SAMPLES)	+= markers/ kobject/ kprobes/ tracepoints/ trace_events/
+obj-$(CONFIG_SAMPLES)	+= kobject/ kprobes/ tracepoints/ trace_events/

samples/markers/Makefile

-# builds the kprobes example kernel modules;
-# then to use one (as root):  insmod <module_name.ko>
-
-obj-$(CONFIG_SAMPLE_MARKERS) += probe-example.o marker-example.o

samples/markers/marker-example.c

-/* marker-example.c
- *
- * Executes a marker when /proc/marker-example is opened.
- *
- * (C) Copyright 2007 Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
- *
- * This file is released under the GPLv2.
- * See the file COPYING for more details.
- */
-
-#include <linux/module.h>
-#include <linux/marker.h>
-#include <linux/sched.h>
-#include <linux/proc_fs.h>
-
-struct proc_dir_entry *pentry_example;
-
-static int my_open(struct inode *inode, struct file *file)
-{
-	int i;
-
-	trace_mark(subsystem_event, "integer %d string %s", 123,
-		"example string");
-	for (i = 0; i < 10; i++)
-		trace_mark(subsystem_eventb, MARK_NOARGS);
-	return -EPERM;
-}
-
-static struct file_operations mark_ops = {
-	.open = my_open,
-};
-
-static int __init example_init(void)
-{
-	printk(KERN_ALERT "example init\n");
-	pentry_example = proc_create("marker-example", 0444, NULL, &mark_ops);
-	if (!pentry_example)
-		return -EPERM;
-	return 0;
-}
-
-static void __exit example_exit(void)
-{
-	printk(KERN_ALERT "example exit\n");
-	remove_proc_entry("marker-example", NULL);
-}
-
-module_init(example_init)
-module_exit(example_exit)
-
-MODULE_LICENSE("GPL");
-MODULE_AUTHOR("Mathieu Desnoyers");
-MODULE_DESCRIPTION("Marker example");

samples/markers/probe-example.c

-/* probe-example.c
- *
- * Connects two functions to marker call sites.
- *
- * (C) Copyright 2007 Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
- *
- * This file is released under the GPLv2.
- * See the file COPYING for more details.
- */
-
-#include <linux/sched.h>
-#include <linux/kernel.h>
-#include <linux/module.h>
-#include <linux/marker.h>
-#include <asm/atomic.h>
-
-struct probe_data {
-	const char *name;
-	const char *format;
-	marker_probe_func *probe_func;
-};
-
-void probe_subsystem_event(void *probe_data, void *call_data,
-	const char *format, va_list *args)
-{
-	/* Declare args */
-	unsigned int value;
-	const char *mystr;
-
-	/* Assign args */
-	value = va_arg(*args, typeof(value));
-	mystr = va_arg(*args, typeof(mystr));
-
-	/* Call printk */
-	printk(KERN_INFO "Value %u, string %s\n", value, mystr);
-
-	/* or count, check rights, serialize data in a buffer */
-}
-
-atomic_t eventb_count = ATOMIC_INIT(0);
-
-void probe_subsystem_eventb(void *probe_data, void *call_data,
-	const char *format, va_list *args)
-{
-	/* Increment counter */
-	atomic_inc(&eventb_count);
-}
-
-static struct probe_data probe_array[] =
-{
-	{	.name = "subsystem_event",
-		.format = "integer %d string %s",
-		.probe_func = probe_subsystem_event },
-	{	.name = "subsystem_eventb",
-		.format = MARK_NOARGS,
-		.probe_func = probe_subsystem_eventb },
-};
-
-static int __init probe_init(void)
-{
-	int result;
-	int i;
-
-	for (i = 0; i < ARRAY_SIZE(probe_array); i++) {
-		result = marker_probe_register(probe_array[i].name,
-				probe_array[i].format,
-				probe_array[i].probe_func, &probe_array[i]);
-		if (result)
-			printk(KERN_INFO "Unable to register probe %s\n",
-				probe_array[i].name);
-	}
-	return 0;
-}
-
-static void __exit probe_fini(void)
-{
-	int i;
-
-	for (i = 0; i < ARRAY_SIZE(probe_array); i++)
-		marker_probe_unregister(probe_array[i].name,
-			probe_array[i].probe_func, &probe_array[i]);
-	printk(KERN_INFO "Number of event b : %u\n",
-			atomic_read(&eventb_count));
-	marker_synchronize_unregister();
-}
-
-module_init(probe_init);
-module_exit(probe_fini);
-
-MODULE_LICENSE("GPL");
-MODULE_AUTHOR("Mathieu Desnoyers");
-MODULE_DESCRIPTION("SUBSYSTEM Probe");

scripts/Makefile.modpost

@@ -13,7 +13,6 @@
 # 2) modpost is then used to
 # 3)  create one <module>.mod.c file pr. module
 # 4)  create one Module.symvers file with CRC for all exported symbols
-# 4a) [CONFIG_MARKERS] create one Module.markers file listing defined markers
 # 5) compile all <module>.mod.c files
 # 6) final link of the module to a <module.ko> file
 
@@ -59,10 +58,6 @@ include scripts/Makefile.lib
 
 kernelsymfile := $(objtree)/Module.symvers
 modulesymfile := $(firstword $(KBUILD_EXTMOD))/Module.symvers
-kernelmarkersfile := $(objtree)/Module.markers
-modulemarkersfile := $(firstword $(KBUILD_EXTMOD))/Module.markers
-
-markersfile = $(if $(KBUILD_EXTMOD),$(modulemarkersfile),$(kernelmarkersfile))
 
 # Step 1), find all modules listed in $(MODVERDIR)/
 __modules := $(sort $(shell grep -h '\.ko' /dev/null $(wildcard $(MODVERDIR)/*.mod)))
@@ -85,8 +80,6 @@ modpost = scripts/mod/modpost                    \
  $(if $(KBUILD_EXTRA_SYMBOLS), $(patsubst %, -e %,$(KBUILD_EXTRA_SYMBOLS))) \
  $(if $(KBUILD_EXTMOD),-o $(modulesymfile))      \
  $(if $(CONFIG_DEBUG_SECTION_MISMATCH),,-S)      \
- $(if $(CONFIG_MARKERS),-K $(kernelmarkersfile)) \
- $(if $(CONFIG_MARKERS),-M $(markersfile))	 \
  $(if $(KBUILD_EXTMOD)$(KBUILD_MODPOST_WARN),-w) \
  $(if $(cross_build),-c)
 
@@ -101,17 +94,12 @@ quiet_cmd_kernel-mod = MODPOST $@
       cmd_kernel-mod = $(modpost) $@
 
 vmlinux.o: FORCE
-	@rm -fr $(kernelmarkersfile)
 	$(call cmd,kernel-mod)
 
 # Declare generated files as targets for modpost
 $(symverfile):         __modpost ;
 $(modules:.ko=.mod.c): __modpost ;
 
-ifdef CONFIG_MARKERS
-$(markersfile):	       __modpost ;
-endif
-
 
 # Step 5), compile all *.mod.c files