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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 41a7dd420c),
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: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Reviewed-by: Oleg 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: zhangwei(Jovi) <jovi.zhangwei@huawei.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This commit is contained in:
zhangwei(Jovi) 2014-01-17 17:08:38 +09:00 committed by Steven Rostedt
parent dd9fa555d7
commit 70ed91c6ec
3 changed files with 101 additions and 38 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

17
kernel/trace/trace_kprobe.c
View File

@ -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.

17
kernel/trace/trace_probe.h
View File

@ -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);

105
kernel/trace/trace_uprobe.c
View File

@ -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 */
@ -855,12 +872,31 @@ 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))
return -EINTR;
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)
@ -868,24 +904,49 @@ probe_event_enable(struct trace_uprobe *tu, int flag, filter_func_t filter)
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: