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Commit 70ed91c6 authored by zhangwei(Jovi)'s avatar zhangwei(Jovi) Committed by Steven Rostedt
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tracing/uprobes: Support ftrace_event_file base multibuffer 

Support multi-buffer on uprobe-based dynamic events by
using ftrace_event_file.

This patch is based kprobe-based dynamic events multibuffer
support work initially, commited by Masami(commit 41a7dd42),
but revised as below:

Oleg changed the kprobe-based multibuffer design from
array-pointers of ftrace_event_file into simple list,
so this patch also change to the list design.

rcu_read_lock/unlock added into uprobe_trace_func/uretprobe_trace_func,
to synchronize with ftrace_event_file list add and delete.

Even though we allow multi-uprobes instances now,
but TP_FLAG_PROFILE/TP_FLAG_TRACE are still mutually exclusive
in probe_event_enable currently, this means we cannot allow
one user is using uprobe-tracer, and another user is using
perf-probe on same uprobe concurrently.
(Perhaps this will be fix in future, kprobe don't have this
limitation now)

Link: http://lkml.kernel.org/r/1389946120-19610-4-git-send-email-namhyung@kernel.org



Reviewed-by: default avatarMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Reviewed-by: default avatarOleg Nesterov <oleg@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: default avatarzhangwei(Jovi) <jovi.zhangwei@huawei.com>
Signed-off-by: default avatarNamhyung Kim <namhyung@kernel.org>
Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
parent dd9fa555

kernel/trace/trace_kprobe.c

+0 −17
Original line number Diff line number Diff line
@@ -35,11 +35,6 @@ struct trace_kprobe { 
	struct trace_probe	tp;

};



struct event_file_link {

	struct ftrace_event_file	*file;

	struct list_head		list;

};



#define SIZEOF_TRACE_KPROBE(n)				\

	(offsetof(struct trace_kprobe, tp.args) +	\

	(sizeof(struct probe_arg) * (n)))
@@ -387,18 +382,6 @@ enable_trace_kprobe(struct trace_kprobe *tk, struct ftrace_event_file *file) 
	return ret;

}



static struct event_file_link *

find_event_file_link(struct trace_probe *tp, struct ftrace_event_file *file)

{

	struct event_file_link *link;



	list_for_each_entry(link, &tp->files, list)

		if (link->file == file)

			return link;



	return NULL;

}



/*

 * Disable trace_probe

 * if the file is NULL, disable "perf" handler, or disable "trace" handler.

kernel/trace/trace_probe.h

+17 −0
Original line number Diff line number Diff line
@@ -288,6 +288,11 @@ struct trace_probe { 
	struct probe_arg		args[];

};



struct event_file_link {

	struct ftrace_event_file	*file;

	struct list_head		list;

};



static inline bool trace_probe_is_enabled(struct trace_probe *tp)

{

	return !!(tp->flags & (TP_FLAG_TRACE | TP_FLAG_PROFILE));
@@ -316,6 +321,18 @@ static inline int is_good_name(const char *name) 
	return 1;

}



static inline struct event_file_link *

find_event_file_link(struct trace_probe *tp, struct ftrace_event_file *file)

{

	struct event_file_link *link;



	list_for_each_entry(link, &tp->files, list)

		if (link->file == file)

			return link;



	return NULL;

}



extern int traceprobe_parse_probe_arg(char *arg, ssize_t *size,

		   struct probe_arg *parg, bool is_return, bool is_kprobe);

kernel/trace/trace_uprobe.c

+84 −21
Original line number Diff line number Diff line
@@ -260,6 +260,7 @@ alloc_trace_uprobe(const char *group, const char *event, int nargs, bool is_ret) 
		goto error;



	INIT_LIST_HEAD(&tu->list);

	INIT_LIST_HEAD(&tu->tp.files);

	tu->consumer.handler = uprobe_dispatcher;

	if (is_ret)

		tu->consumer.ret_handler = uretprobe_dispatcher;
@@ -760,7 +761,8 @@ static void uprobe_buffer_put(struct uprobe_cpu_buffer *ucb) 


static void __uprobe_trace_func(struct trace_uprobe *tu,

				unsigned long func, struct pt_regs *regs,

				struct uprobe_cpu_buffer *ucb, int dsize)

				struct uprobe_cpu_buffer *ucb, int dsize,

				struct ftrace_event_file *ftrace_file)

{

	struct uprobe_trace_entry_head *entry;

	struct ring_buffer_event *event;
@@ -769,13 +771,15 @@ static void __uprobe_trace_func(struct trace_uprobe *tu, 
	int size, esize;

	struct ftrace_event_call *call = &tu->tp.call;



	WARN_ON(call != ftrace_file->event_call);



	if (WARN_ON_ONCE(tu->tp.size + dsize > PAGE_SIZE))

		return;



	esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));

	size = esize + tu->tp.size + dsize;

	event = trace_current_buffer_lock_reserve(&buffer, call->event.type,

						  size, 0, 0);

	event = trace_event_buffer_lock_reserve(&buffer, ftrace_file,

						call->event.type, size, 0, 0);

	if (!event)

		return;
@@ -799,8 +803,16 @@ static void __uprobe_trace_func(struct trace_uprobe *tu, 
static int uprobe_trace_func(struct trace_uprobe *tu, struct pt_regs *regs,

			     struct uprobe_cpu_buffer *ucb, int dsize)

{

	if (!is_ret_probe(tu))

		__uprobe_trace_func(tu, 0, regs, ucb, dsize);

	struct event_file_link *link;



	if (is_ret_probe(tu))

		return 0;



	rcu_read_lock();

	list_for_each_entry_rcu(link, &tu->tp.files, list)

		__uprobe_trace_func(tu, 0, regs, ucb, dsize, link->file);

	rcu_read_unlock();



	return 0;

}
@@ -808,7 +820,12 @@ static void uretprobe_trace_func(struct trace_uprobe *tu, unsigned long func, 
				 struct pt_regs *regs,

				 struct uprobe_cpu_buffer *ucb, int dsize)

{

	__uprobe_trace_func(tu, func, regs, ucb, dsize);

	struct event_file_link *link;



	rcu_read_lock();

	list_for_each_entry_rcu(link, &tu->tp.files, list)

		__uprobe_trace_func(tu, func, regs, ucb, dsize, link->file);

	rcu_read_unlock();

}



/* Event entry printers */
@@ -855,37 +872,81 @@ typedef bool (*filter_func_t)(struct uprobe_consumer *self, 
				struct mm_struct *mm);



static int

probe_event_enable(struct trace_uprobe *tu, int flag, filter_func_t filter)

probe_event_enable(struct trace_uprobe *tu, struct ftrace_event_file *file,

		   filter_func_t filter)

{

	int ret = 0;

	bool enabled = trace_probe_is_enabled(&tu->tp);

	struct event_file_link *link = NULL;

	int ret;



	if (trace_probe_is_enabled(&tu->tp))

	if (file) {

		if (tu->tp.flags & TP_FLAG_PROFILE)

			return -EINTR;



		link = kmalloc(sizeof(*link), GFP_KERNEL);

		if (!link)

			return -ENOMEM;



		link->file = file;

		list_add_tail_rcu(&link->list, &tu->tp.files);



		tu->tp.flags |= TP_FLAG_TRACE;

	} else {

		if (tu->tp.flags & TP_FLAG_TRACE)

			return -EINTR;



		tu->tp.flags |= TP_FLAG_PROFILE;

	}



	ret = uprobe_buffer_enable();

	if (ret < 0)

		return ret;



	WARN_ON(!uprobe_filter_is_empty(&tu->filter));



	tu->tp.flags |= flag;

	if (enabled)

		return 0;



	tu->consumer.filter = filter;

	ret = uprobe_register(tu->inode, tu->offset, &tu->consumer);

	if (ret)

		tu->tp.flags &= ~flag;

	if (ret) {

		if (file) {

			list_del(&link->list);

			kfree(link);

			tu->tp.flags &= ~TP_FLAG_TRACE;

		} else

			tu->tp.flags &= ~TP_FLAG_PROFILE;

	}



	return ret;

}



static void probe_event_disable(struct trace_uprobe *tu, int flag)

static void

probe_event_disable(struct trace_uprobe *tu, struct ftrace_event_file *file)

{

	if (!trace_probe_is_enabled(&tu->tp))

		return;



	if (file) {

		struct event_file_link *link;



		link = find_event_file_link(&tu->tp, file);

		if (!link)

			return;



		list_del_rcu(&link->list);

		/* synchronize with u{,ret}probe_trace_func */

		synchronize_sched();

		kfree(link);



		if (!list_empty(&tu->tp.files))

			return;

	}



	WARN_ON(!uprobe_filter_is_empty(&tu->filter));



	uprobe_unregister(tu->inode, tu->offset, &tu->consumer);

	tu->tp.flags &= ~flag;

	tu->tp.flags &= file ? ~TP_FLAG_TRACE : ~TP_FLAG_PROFILE;



	uprobe_buffer_disable();

}
@@ -1077,25 +1138,27 @@ static void uretprobe_perf_func(struct trace_uprobe *tu, unsigned long func, 
}

#endif	/* CONFIG_PERF_EVENTS */



static

int trace_uprobe_register(struct ftrace_event_call *event, enum trace_reg type, void *data)

static int

trace_uprobe_register(struct ftrace_event_call *event, enum trace_reg type,

		      void *data)

{

	struct trace_uprobe *tu = event->data;

	struct ftrace_event_file *file = data;



	switch (type) {

	case TRACE_REG_REGISTER:

		return probe_event_enable(tu, TP_FLAG_TRACE, NULL);

		return probe_event_enable(tu, file, NULL);



	case TRACE_REG_UNREGISTER:

		probe_event_disable(tu, TP_FLAG_TRACE);

		probe_event_disable(tu, file);

		return 0;



#ifdef CONFIG_PERF_EVENTS

	case TRACE_REG_PERF_REGISTER:

		return probe_event_enable(tu, TP_FLAG_PROFILE, uprobe_perf_filter);

		return probe_event_enable(tu, NULL, uprobe_perf_filter);



	case TRACE_REG_PERF_UNREGISTER:

		probe_event_disable(tu, TP_FLAG_PROFILE);

		probe_event_disable(tu, NULL);

		return 0;



	case TRACE_REG_PERF_OPEN: