]> asedeno.scripts.mit.edu Git - linux.git/commitdiff
tracing/uprobes: Use dyn_event framework for uprobe events
authorMasami Hiramatsu <mhiramat@kernel.org>
Mon, 5 Nov 2018 09:03:04 +0000 (18:03 +0900)
committerSteven Rostedt (VMware) <rostedt@goodmis.org>
Sun, 9 Dec 2018 01:54:10 +0000 (20:54 -0500)
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.

Link: http://lkml.kernel.org/r/154140858481.17322.9091293846515154065.stgit@devbox
Reviewed-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Tested-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Documentation/trace/uprobetracer.rst
kernel/trace/Kconfig
kernel/trace/trace_uprobe.c

index d0822811527ac9654a7246eb6bd849ba220e151d..4c3bfde2ba477d31588a1577f98968a098b193bf 100644 (file)
@@ -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
 -------------------------
 ::
index c0f6b0105609288a3cb0d26ddc2e1a82db282202..2cab3c5dfe2c38980994e0533abc2665adef4b27 100644 (file)
@@ -501,6 +501,7 @@ config UPROBE_EVENTS
        depends on PERF_EVENTS
        select UPROBES
        select PROBE_EVENTS
+       select DYNAMIC_EVENTS
        select TRACING
        default y
        help
index 6eaaa21506857fd5f5f9dd1ed57c7b5a2079bde1..4a7b21c891f3dd5cb483c62a6bec21ce60812340 100644 (file)
@@ -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))