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Message-Id: <154140858481.17322.9091293846515154065.stgit@devbox>
Date: Mon, 5 Nov 2018 18:03:04 +0900
From: Masami Hiramatsu <mhiramat@...nel.org>
To: Steven Rostedt <rostedt@...dmis.org>
Cc: linux-kernel@...r.kernel.org, Ingo Molnar <mingo@...nel.org>,
Tom Zanussi <tom.zanussi@...ux.intel.com>,
Ravi Bangoria <ravi.bangoria@...ux.vnet.ibm.com>
Subject: [PATCH v2 07/12] tracing/uprobes: Use dyn_event framework for uprobe events
Use dyn_event framework for uprobe events. This shows
uprobe events on "dynamic_events" file.
User can also define new uprobe events via dynamic_events.
Signed-off-by: Masami Hiramatsu <mhiramat@...nel.org>
---
Changes in v2:
- Use dyn_events_release_all() for clearing events.
- Use nolock event_call register/unregister and lock event_mutex
before dyn_event_mutex to avoid lock dependency error.
- Select CONFIG_DYNAMIC_EVENTS in Kconfig
- Add match operation and use new API for event deletion
- Return -ECANCELED if given event is not for uprobe.
- Remove unused for_each_trace_uprobe_safe.
---
Documentation/trace/uprobetracer.rst | 4
kernel/trace/Kconfig | 1
kernel/trace/trace_uprobe.c | 278 ++++++++++++++++++----------------
3 files changed, 153 insertions(+), 130 deletions(-)
diff --git a/Documentation/trace/uprobetracer.rst b/Documentation/trace/uprobetracer.rst
index d0822811527a..4c3bfde2ba47 100644
--- a/Documentation/trace/uprobetracer.rst
+++ b/Documentation/trace/uprobetracer.rst
@@ -18,6 +18,10 @@ current_tracer. Instead of that, add probe points via
However unlike kprobe-event tracer, the uprobe event interface expects the
user to calculate the offset of the probepoint in the object.
+You can also use /sys/kernel/debug/tracing/dynamic_events instead of
+uprobe_events. That interface will provide unified access to other
+dynamic events too.
+
Synopsis of uprobe_tracer
-------------------------
::
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index c0f6b0105609..2cab3c5dfe2c 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -501,6 +501,7 @@ config UPROBE_EVENTS
depends on PERF_EVENTS
select UPROBES
select PROBE_EVENTS
+ select DYNAMIC_EVENTS
select TRACING
default y
help
diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
index 6eaaa2150685..4a7b21c891f3 100644
--- a/kernel/trace/trace_uprobe.c
+++ b/kernel/trace/trace_uprobe.c
@@ -7,6 +7,7 @@
*/
#define pr_fmt(fmt) "trace_kprobe: " fmt
+#include <linux/ctype.h>
#include <linux/module.h>
#include <linux/uaccess.h>
#include <linux/uprobes.h>
@@ -14,6 +15,7 @@
#include <linux/string.h>
#include <linux/rculist.h>
+#include "trace_dynevent.h"
#include "trace_probe.h"
#include "trace_probe_tmpl.h"
@@ -37,11 +39,26 @@ struct trace_uprobe_filter {
struct list_head perf_events;
};
+static int trace_uprobe_create(int argc, const char **argv);
+static int trace_uprobe_show(struct seq_file *m, struct dyn_event *ev);
+static int trace_uprobe_release(struct dyn_event *ev);
+static bool trace_uprobe_is_busy(struct dyn_event *ev);
+static bool trace_uprobe_match(const char *system, const char *event,
+ struct dyn_event *ev);
+
+static struct dyn_event_operations trace_uprobe_ops = {
+ .create = trace_uprobe_create,
+ .show = trace_uprobe_show,
+ .is_busy = trace_uprobe_is_busy,
+ .free = trace_uprobe_release,
+ .match = trace_uprobe_match,
+};
+
/*
* uprobe event core functions
*/
struct trace_uprobe {
- struct list_head list;
+ struct dyn_event devent;
struct trace_uprobe_filter filter;
struct uprobe_consumer consumer;
struct path path;
@@ -53,6 +70,25 @@ struct trace_uprobe {
struct trace_probe tp;
};
+static bool is_trace_uprobe(struct dyn_event *ev)
+{
+ return ev->ops == &trace_uprobe_ops;
+}
+
+static struct trace_uprobe *to_trace_uprobe(struct dyn_event *ev)
+{
+ return container_of(ev, struct trace_uprobe, devent);
+}
+
+/**
+ * for_each_trace_uprobe - iterate over the trace_uprobe list
+ * @pos: the struct trace_uprobe * for each entry
+ * @dpos: the struct dyn_event * to use as a loop cursor
+ */
+#define for_each_trace_uprobe(pos, dpos) \
+ for_each_dyn_event(dpos) \
+ if (is_trace_uprobe(dpos) && (pos = to_trace_uprobe(dpos)))
+
#define SIZEOF_TRACE_UPROBE(n) \
(offsetof(struct trace_uprobe, tp.args) + \
(sizeof(struct probe_arg) * (n)))
@@ -60,9 +96,6 @@ struct trace_uprobe {
static int register_uprobe_event(struct trace_uprobe *tu);
static int unregister_uprobe_event(struct trace_uprobe *tu);
-static DEFINE_MUTEX(uprobe_lock);
-static LIST_HEAD(uprobe_list);
-
struct uprobe_dispatch_data {
struct trace_uprobe *tu;
unsigned long bp_addr;
@@ -209,6 +242,22 @@ static inline bool is_ret_probe(struct trace_uprobe *tu)
return tu->consumer.ret_handler != NULL;
}
+static bool trace_uprobe_is_busy(struct dyn_event *ev)
+{
+ struct trace_uprobe *tu = to_trace_uprobe(ev);
+
+ return trace_probe_is_enabled(&tu->tp);
+}
+
+static bool trace_uprobe_match(const char *system, const char *event,
+ struct dyn_event *ev)
+{
+ struct trace_uprobe *tu = to_trace_uprobe(ev);
+
+ return strcmp(trace_event_name(&tu->tp.call), event) == 0 &&
+ (!system || strcmp(tu->tp.call.class->system, system) == 0);
+}
+
/*
* Allocate new trace_uprobe and initialize it (including uprobes).
*/
@@ -236,7 +285,7 @@ alloc_trace_uprobe(const char *group, const char *event, int nargs, bool is_ret)
if (!tu->tp.class.system)
goto error;
- INIT_LIST_HEAD(&tu->list);
+ dyn_event_init(&tu->devent, &trace_uprobe_ops);
INIT_LIST_HEAD(&tu->tp.files);
tu->consumer.handler = uprobe_dispatcher;
if (is_ret)
@@ -255,6 +304,9 @@ static void free_trace_uprobe(struct trace_uprobe *tu)
{
int i;
+ if (!tu)
+ return;
+
for (i = 0; i < tu->tp.nr_args; i++)
traceprobe_free_probe_arg(&tu->tp.args[i]);
@@ -267,9 +319,10 @@ static void free_trace_uprobe(struct trace_uprobe *tu)
static struct trace_uprobe *find_probe_event(const char *event, const char *group)
{
+ struct dyn_event *pos;
struct trace_uprobe *tu;
- list_for_each_entry(tu, &uprobe_list, list)
+ for_each_trace_uprobe(tu, pos)
if (strcmp(trace_event_name(&tu->tp.call), event) == 0 &&
strcmp(tu->tp.call.class->system, group) == 0)
return tu;
@@ -277,7 +330,7 @@ static struct trace_uprobe *find_probe_event(const char *event, const char *grou
return NULL;
}
-/* Unregister a trace_uprobe and probe_event: call with locking uprobe_lock */
+/* Unregister a trace_uprobe and probe_event */
static int unregister_trace_uprobe(struct trace_uprobe *tu)
{
int ret;
@@ -286,7 +339,7 @@ static int unregister_trace_uprobe(struct trace_uprobe *tu)
if (ret)
return ret;
- list_del(&tu->list);
+ dyn_event_remove(&tu->devent);
free_trace_uprobe(tu);
return 0;
}
@@ -302,13 +355,14 @@ static int unregister_trace_uprobe(struct trace_uprobe *tu)
*/
static struct trace_uprobe *find_old_trace_uprobe(struct trace_uprobe *new)
{
+ struct dyn_event *pos;
struct trace_uprobe *tmp, *old = NULL;
struct inode *new_inode = d_real_inode(new->path.dentry);
old = find_probe_event(trace_event_name(&new->tp.call),
new->tp.call.class->system);
- list_for_each_entry(tmp, &uprobe_list, list) {
+ for_each_trace_uprobe(tmp, pos) {
if ((old ? old != tmp : true) &&
new_inode == d_real_inode(tmp->path.dentry) &&
new->offset == tmp->offset &&
@@ -326,7 +380,7 @@ static int register_trace_uprobe(struct trace_uprobe *tu)
struct trace_uprobe *old_tu;
int ret;
- mutex_lock(&uprobe_lock);
+ mutex_lock(&event_mutex);
/* register as an event */
old_tu = find_old_trace_uprobe(tu);
@@ -348,10 +402,10 @@ static int register_trace_uprobe(struct trace_uprobe *tu)
goto end;
}
- list_add_tail(&tu->list, &uprobe_list);
+ dyn_event_add(&tu->devent);
end:
- mutex_unlock(&uprobe_lock);
+ mutex_unlock(&event_mutex);
return ret;
}
@@ -362,91 +416,49 @@ static int register_trace_uprobe(struct trace_uprobe *tu)
*
* - Remove uprobe: -:[GRP/]EVENT
*/
-static int create_trace_uprobe(int argc, char **argv)
+static int trace_uprobe_create(int argc, const char **argv)
{
struct trace_uprobe *tu;
- char *arg, *event, *group, *filename, *rctr, *rctr_end;
+ const char *event = NULL, *group = UPROBE_EVENT_SYSTEM;
+ char *arg, *filename, *rctr, *rctr_end, *tmp;
char buf[MAX_EVENT_NAME_LEN];
struct path path;
unsigned long offset, ref_ctr_offset;
- bool is_delete, is_return;
+ bool is_return = false;
int i, ret;
ret = 0;
- is_delete = false;
- is_return = false;
- event = NULL;
- group = NULL;
ref_ctr_offset = 0;
/* argc must be >= 1 */
- if (argv[0][0] == '-')
- is_delete = true;
- else if (argv[0][0] == 'r')
+ if (argv[0][0] == 'r')
is_return = true;
- else if (argv[0][0] != 'p') {
- pr_info("Probe definition must be started with 'p', 'r' or '-'.\n");
- return -EINVAL;
- }
+ else if (argv[0][0] != 'p' || argc < 2)
+ return -ECANCELED;
- if (argv[0][1] == ':') {
+ if (argv[0][1] == ':')
event = &argv[0][2];
- arg = strchr(event, '/');
- if (arg) {
- group = event;
- event = arg + 1;
- event[-1] = '\0';
+ if (!strchr(argv[1], '/'))
+ return -ECANCELED;
- if (strlen(group) == 0) {
- pr_info("Group name is not specified\n");
- return -EINVAL;
- }
- }
- if (strlen(event) == 0) {
- pr_info("Event name is not specified\n");
- return -EINVAL;
- }
- }
- if (!group)
- group = UPROBE_EVENT_SYSTEM;
-
- if (is_delete) {
- int ret;
-
- if (!event) {
- pr_info("Delete command needs an event name.\n");
- return -EINVAL;
- }
- mutex_lock(&uprobe_lock);
- tu = find_probe_event(event, group);
-
- if (!tu) {
- mutex_unlock(&uprobe_lock);
- pr_info("Event %s/%s doesn't exist.\n", group, event);
- return -ENOENT;
- }
- /* delete an event */
- ret = unregister_trace_uprobe(tu);
- mutex_unlock(&uprobe_lock);
- return ret;
- }
+ filename = kstrdup(argv[1], GFP_KERNEL);
+ if (!filename)
+ return -ENOMEM;
- if (argc < 2) {
- pr_info("Probe point is not specified.\n");
- return -EINVAL;
- }
/* Find the last occurrence, in case the path contains ':' too. */
- arg = strrchr(argv[1], ':');
- if (!arg)
- return -EINVAL;
+ arg = strrchr(filename, ':');
+ if (!arg || !isdigit(arg[1])) {
+ kfree(filename);
+ return -ECANCELED;
+ }
*arg++ = '\0';
- filename = argv[1];
ret = kern_path(filename, LOOKUP_FOLLOW, &path);
- if (ret)
+ if (ret) {
+ kfree(filename);
return ret;
-
+ }
if (!d_is_reg(path.dentry)) {
ret = -EINVAL;
goto fail_address_parse;
@@ -480,7 +492,11 @@ static int create_trace_uprobe(int argc, char **argv)
argv += 2;
/* setup a probe */
- if (!event) {
+ if (event) {
+ ret = traceprobe_parse_event_name(&event, &group, buf);
+ if (ret)
+ goto fail_address_parse;
+ } else {
char *tail;
char *ptr;
@@ -508,18 +524,19 @@ static int create_trace_uprobe(int argc, char **argv)
tu->offset = offset;
tu->ref_ctr_offset = ref_ctr_offset;
tu->path = path;
- tu->filename = kstrdup(filename, GFP_KERNEL);
-
- if (!tu->filename) {
- pr_info("Failed to allocate filename.\n");
- ret = -ENOMEM;
- goto error;
- }
+ tu->filename = filename;
/* parse arguments */
for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
- ret = traceprobe_parse_probe_arg(&tu->tp, i, argv[i],
+ tmp = kstrdup(argv[i], GFP_KERNEL);
+ if (!tmp) {
+ ret = -ENOMEM;
+ goto error;
+ }
+
+ ret = traceprobe_parse_probe_arg(&tu->tp, i, tmp,
is_return ? TPARG_FL_RETURN : 0);
+ kfree(tmp);
if (ret)
goto error;
}
@@ -535,55 +552,35 @@ static int create_trace_uprobe(int argc, char **argv)
fail_address_parse:
path_put(&path);
+ kfree(filename);
pr_info("Failed to parse address or file.\n");
return ret;
}
-static int cleanup_all_probes(void)
+static int create_or_delete_trace_uprobe(int argc, char **argv)
{
- struct trace_uprobe *tu;
- int ret = 0;
+ int ret;
- mutex_lock(&uprobe_lock);
- /* Ensure no probe is in use. */
- list_for_each_entry(tu, &uprobe_list, list)
- if (trace_probe_is_enabled(&tu->tp)) {
- ret = -EBUSY;
- goto end;
- }
- while (!list_empty(&uprobe_list)) {
- tu = list_entry(uprobe_list.next, struct trace_uprobe, list);
- ret = unregister_trace_uprobe(tu);
- if (ret)
- break;
- }
-end:
- mutex_unlock(&uprobe_lock);
- return ret;
-}
+ if (argv[0][0] == '-')
+ return dyn_event_release(argc, argv, &trace_uprobe_ops);
-/* Probes listing interfaces */
-static void *probes_seq_start(struct seq_file *m, loff_t *pos)
-{
- mutex_lock(&uprobe_lock);
- return seq_list_start(&uprobe_list, *pos);
+ ret = trace_uprobe_create(argc, (const char **)argv);
+ return ret == -ECANCELED ? -EINVAL : ret;
}
-static void *probes_seq_next(struct seq_file *m, void *v, loff_t *pos)
+static int trace_uprobe_release(struct dyn_event *ev)
{
- return seq_list_next(v, &uprobe_list, pos);
-}
+ struct trace_uprobe *tu = to_trace_uprobe(ev);
-static void probes_seq_stop(struct seq_file *m, void *v)
-{
- mutex_unlock(&uprobe_lock);
+ return unregister_trace_uprobe(tu);
}
-static int probes_seq_show(struct seq_file *m, void *v)
+/* Probes listing interfaces */
+static int trace_uprobe_show(struct seq_file *m, struct dyn_event *ev)
{
- struct trace_uprobe *tu = v;
+ struct trace_uprobe *tu = to_trace_uprobe(ev);
char c = is_ret_probe(tu) ? 'r' : 'p';
int i;
@@ -601,11 +598,21 @@ static int probes_seq_show(struct seq_file *m, void *v)
return 0;
}
+static int probes_seq_show(struct seq_file *m, void *v)
+{
+ struct dyn_event *ev = v;
+
+ if (!is_trace_uprobe(ev))
+ return 0;
+
+ return trace_uprobe_show(m, ev);
+}
+
static const struct seq_operations probes_seq_op = {
- .start = probes_seq_start,
- .next = probes_seq_next,
- .stop = probes_seq_stop,
- .show = probes_seq_show
+ .start = dyn_event_seq_start,
+ .next = dyn_event_seq_next,
+ .stop = dyn_event_seq_stop,
+ .show = probes_seq_show
};
static int probes_open(struct inode *inode, struct file *file)
@@ -613,7 +620,7 @@ static int probes_open(struct inode *inode, struct file *file)
int ret;
if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
- ret = cleanup_all_probes();
+ ret = dyn_events_release_all(&trace_uprobe_ops);
if (ret)
return ret;
}
@@ -624,7 +631,8 @@ static int probes_open(struct inode *inode, struct file *file)
static ssize_t probes_write(struct file *file, const char __user *buffer,
size_t count, loff_t *ppos)
{
- return trace_parse_run_command(file, buffer, count, ppos, create_trace_uprobe);
+ return trace_parse_run_command(file, buffer, count, ppos,
+ create_or_delete_trace_uprobe);
}
static const struct file_operations uprobe_events_ops = {
@@ -639,17 +647,22 @@ static const struct file_operations uprobe_events_ops = {
/* Probes profiling interfaces */
static int probes_profile_seq_show(struct seq_file *m, void *v)
{
- struct trace_uprobe *tu = v;
+ struct dyn_event *ev = v;
+ struct trace_uprobe *tu;
+
+ if (!is_trace_uprobe(ev))
+ return 0;
+ tu = to_trace_uprobe(ev);
seq_printf(m, " %s %-44s %15lu\n", tu->filename,
trace_event_name(&tu->tp.call), tu->nhit);
return 0;
}
static const struct seq_operations profile_seq_op = {
- .start = probes_seq_start,
- .next = probes_seq_next,
- .stop = probes_seq_stop,
+ .start = dyn_event_seq_start,
+ .next = dyn_event_seq_next,
+ .stop = dyn_event_seq_stop,
.show = probes_profile_seq_show
};
@@ -1307,7 +1320,7 @@ static int register_uprobe_event(struct trace_uprobe *tu)
return -ENODEV;
}
- ret = trace_add_event_call(call);
+ ret = trace_add_event_call_nolock(call);
if (ret) {
pr_info("Failed to register uprobe event: %s\n",
@@ -1324,7 +1337,7 @@ static int unregister_uprobe_event(struct trace_uprobe *tu)
int ret;
/* tu->event is unregistered in trace_remove_event_call() */
- ret = trace_remove_event_call(&tu->tp.call);
+ ret = trace_remove_event_call_nolock(&tu->tp.call);
if (ret)
return ret;
kfree(tu->tp.call.print_fmt);
@@ -1351,7 +1364,7 @@ create_local_trace_uprobe(char *name, unsigned long offs,
}
/*
- * local trace_kprobes are not added to probe_list, so they are never
+ * local trace_kprobes are not added to dyn_event, so they are never
* searched in find_trace_kprobe(). Therefore, there is no concern of
* duplicated name "DUMMY_EVENT" here.
*/
@@ -1399,6 +1412,11 @@ void destroy_local_trace_uprobe(struct trace_event_call *event_call)
static __init int init_uprobe_trace(void)
{
struct dentry *d_tracer;
+ int ret;
+
+ ret = dyn_event_register(&trace_uprobe_ops);
+ if (ret)
+ return ret;
d_tracer = tracing_init_dentry();
if (IS_ERR(d_tracer))
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