tracing: Auto generate event name when creating a group of events

Currently when creating a specific group of trace events,
take kprobe event as example, the user must use the following format:
p:GRP/EVENT [MOD:]KSYM[+OFFS]|KADDR [FETCHARGS],
which means user must enter EVENT name, one example is:

  echo 'p:usb_gadget/config_usb_cfg_link config_usb_cfg_link $arg1' >> kprobe_events

It is not simple if there are too many entries because the event name is
the same as symbol name.

This change allows user to specify no EVENT name, format changed as:

   p:GRP/ [MOD:]KSYM[+OFFS]|KADDR [FETCHARGS]

It will generate event name automatically and one example is:

  echo 'p:usb_gadget/ config_usb_cfg_link $arg1' >> kprobe_events.

Link: https://lore.kernel.org/all/1656296348-16111-4-git-send-email-quic_linyyuan@quicinc.com/
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Reviewed-by: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Linyu Yuan <quic_linyyuan@quicinc.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

diff --git a/Documentation/trace/kprobetrace.rst b/Documentation/trace/kprobetrace.rst
index b175d88..4274cc6 100644 (file)
--- a/Documentation/trace/kprobetrace.rst
+++ b/Documentation/trace/kprobetrace.rst
@@ -28,10 +28,10 @@ Synopsis of kprobe_events
 -------------------------
 ::
 
-  p[:[GRP/]EVENT] [MOD:]SYM[+offs]|MEMADDR [FETCHARGS] : Set a probe
-  r[MAXACTIVE][:[GRP/]EVENT] [MOD:]SYM[+0] [FETCHARGS] : Set a return probe
-  p:[GRP/]EVENT] [MOD:]SYM[+0]%return [FETCHARGS]      : Set a return probe
-  -:[GRP/]EVENT                                                : Clear a probe
+  p[:[GRP/][EVENT]] [MOD:]SYM[+offs]|MEMADDR [FETCHARGS]       : Set a probe
+  r[MAXACTIVE][:[GRP/][EVENT]] [MOD:]SYM[+0] [FETCHARGS]       : Set a return probe
+  p[:[GRP/][EVENT]] [MOD:]SYM[+0]%return [FETCHARGS]   : Set a return probe
+  -:[GRP/][EVENT]                                              : Clear a probe
 
  GRP           : Group name. If omitted, use "kprobes" for it.
  EVENT         : Event name. If omitted, the event name is generated

diff --git a/Documentation/trace/uprobetracer.rst b/Documentation/trace/uprobetracer.rst
index a8e5938..3a1797d 100644 (file)
--- a/Documentation/trace/uprobetracer.rst
+++ b/Documentation/trace/uprobetracer.rst
@@ -26,10 +26,10 @@ Synopsis of uprobe_tracer
 -------------------------
 ::
 
-  p[:[GRP/]EVENT] PATH:OFFSET [FETCHARGS] : Set a uprobe
-  r[:[GRP/]EVENT] PATH:OFFSET [FETCHARGS] : Set a return uprobe (uretprobe)
-  p[:[GRP/]EVENT] PATH:OFFSET%return [FETCHARGS] : Set a return uprobe (uretprobe)
-  -:[GRP/]EVENT                           : Clear uprobe or uretprobe event
+  p[:[GRP/][EVENT]] PATH:OFFSET [FETCHARGS] : Set a uprobe
+  r[:[GRP/][EVENT]] PATH:OFFSET [FETCHARGS] : Set a return uprobe (uretprobe)
+  p[:[GRP/][EVENT]] PATH:OFFSET%return [FETCHARGS] : Set a return uprobe (uretprobe)
+  -:[GRP/][EVENT]                           : Clear uprobe or uretprobe event
 
   GRP           : Group name. If omitted, "uprobes" is the default value.
   EVENT         : Event name. If omitted, the event name is generated based

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index b8dd546..7eb5bce 100644 (file)
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -5569,13 +5569,13 @@ static const char readme_msg[] =
 #endif
 #if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS)
        "\t  accepts: event-definitions (one definition per line)\n"
-       "\t   Format: p[:[<group>/]<event>] <place> [<args>]\n"
-       "\t           r[maxactive][:[<group>/]<event>] <place> [<args>]\n"
+       "\t   Format: p[:[<group>/][<event>]] <place> [<args>]\n"
+       "\t           r[maxactive][:[<group>/][<event>]] <place> [<args>]\n"
 #ifdef CONFIG_HIST_TRIGGERS
        "\t           s:[synthetic/]<event> <field> [<field>]\n"
 #endif
-       "\t           e[:[<group>/]<event>] <attached-group>.<attached-event> [<args>]\n"
-       "\t           -:[<group>/]<event>\n"
+       "\t           e[:[<group>/][<event>]] <attached-group>.<attached-event> [<args>]\n"
+       "\t           -:[<group>/][<event>]\n"
 #ifdef CONFIG_KPROBE_EVENTS
        "\t    place: [<module>:]<symbol>[+<offset>]|<memaddr>\n"
   "place (kretprobe): [<module>:]<symbol>[+<offset>]%return|<memaddr>\n"

diff --git a/kernel/trace/trace_dynevent.c b/kernel/trace/trace_dynevent.c
index 076b447..1549966 100644 (file)
--- a/kernel/trace/trace_dynevent.c
+++ b/kernel/trace/trace_dynevent.c
@@ -101,7 +101,7 @@ int dyn_event_release(const char *raw_command, struct dyn_event_operations *type
                event = p + 1;
                *p = '\0';
        }
-       if (event[0] == '\0') {
+       if (!system && event[0] == '\0') {
                ret = -EINVAL;
                goto out;
        }

diff --git a/kernel/trace/trace_eprobe.c b/kernel/trace/trace_eprobe.c
index 8979cb9..a30f214 100644 (file)
--- a/kernel/trace/trace_eprobe.c
+++ b/kernel/trace/trace_eprobe.c
@@ -125,6 +125,7 @@ static bool eprobe_dyn_event_match(const char *system, const char *event,
         * We match the following:
         *  event only                  - match all eprobes with event name
         *  system and event only       - match all system/event probes
+        *  system only                 - match all system probes
         *
         * The below has the above satisfied with more arguments:
         *
@@ -143,7 +144,7 @@ static bool eprobe_dyn_event_match(const char *system, const char *event,
                return false;
 
        /* Must match the event name */
-       if (strcmp(trace_probe_name(&ep->tp), event) != 0)
+       if (event[0] != '\0' && strcmp(trace_probe_name(&ep->tp), event) != 0)
                return false;
 
        /* No arguments match all */
@@ -848,7 +849,7 @@ static int __trace_eprobe_create(int argc, const char *argv[])
 {
        /*
         * Argument syntax:
-        *      e[:[GRP/]ENAME] SYSTEM.EVENT [FETCHARGS]
+        *      e[:[GRP/][ENAME]] SYSTEM.EVENT [FETCHARGS]
         * Fetch args:
         *  <name>=$<field>[:TYPE]
         */
@@ -858,6 +859,7 @@ static int __trace_eprobe_create(int argc, const char *argv[])
        struct trace_eprobe *ep = NULL;
        char buf1[MAX_EVENT_NAME_LEN];
        char buf2[MAX_EVENT_NAME_LEN];
+       char gbuf[MAX_EVENT_NAME_LEN];
        int ret = 0;
        int i;
 
@@ -869,25 +871,24 @@ static int __trace_eprobe_create(int argc, const char *argv[])
        event = strchr(&argv[0][1], ':');
        if (event) {
                event++;
-               ret = traceprobe_parse_event_name(&event, &group, buf1,
+               ret = traceprobe_parse_event_name(&event, &group, gbuf,
                                                  event - argv[0]);
                if (ret)
                        goto parse_error;
-       } else {
-               strscpy(buf1, argv[1], MAX_EVENT_NAME_LEN);
-               sanitize_event_name(buf1);
-               event = buf1;
        }
-       if (!is_good_name(event) || !is_good_name(group))
-               goto parse_error;
 
        trace_probe_log_set_index(1);
        sys_event = argv[1];
-       ret = traceprobe_parse_event_name(&sys_event, &sys_name, buf2,
-                                         sys_event - argv[1]);
-       if (ret || !sys_name)
+       ret = traceprobe_parse_event_name(&sys_event, &sys_name, buf2, 0);
+       if (!sys_event || !sys_name)
                goto parse_error;
 
+       if (!event) {
+               strscpy(buf1, argv[1], MAX_EVENT_NAME_LEN);
+               sanitize_event_name(buf1);
+               event = buf1;
+       }
+
        mutex_lock(&event_mutex);
        event_call = find_and_get_event(sys_name, sys_event);
        ep = alloc_event_probe(group, event, event_call, argc - 2);

diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index a245ea6..23f7f0e 100644 (file)
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -163,7 +163,8 @@ static bool trace_kprobe_match(const char *system, const char *event,
 {
        struct trace_kprobe *tk = to_trace_kprobe(ev);
 
-       return strcmp(trace_probe_name(&tk->tp), event) == 0 &&
+       return (event[0] == '\0' ||
+               strcmp(trace_probe_name(&tk->tp), event) == 0) &&
            (!system || strcmp(trace_probe_group_name(&tk->tp), system) == 0) &&
            trace_kprobe_match_command_head(tk, argc, argv);
 }
@@ -708,11 +709,11 @@ static int __trace_kprobe_create(int argc, const char *argv[])
        /*
         * Argument syntax:
         *  - Add kprobe:
-        *      p[:[GRP/]EVENT] [MOD:]KSYM[+OFFS]|KADDR [FETCHARGS]
+        *      p[:[GRP/][EVENT]] [MOD:]KSYM[+OFFS]|KADDR [FETCHARGS]
         *  - Add kretprobe:
-        *      r[MAXACTIVE][:[GRP/]EVENT] [MOD:]KSYM[+0] [FETCHARGS]
+        *      r[MAXACTIVE][:[GRP/][EVENT]] [MOD:]KSYM[+0] [FETCHARGS]
         *    Or
-        *      p:[GRP/]EVENT] [MOD:]KSYM[+0]%return [FETCHARGS]
+        *      p[:[GRP/][EVENT]] [MOD:]KSYM[+0]%return [FETCHARGS]
         *
         * Fetch args:
         *  $retval     : fetch return value
@@ -739,6 +740,7 @@ static int __trace_kprobe_create(int argc, const char *argv[])
        long offset = 0;
        void *addr = NULL;
        char buf[MAX_EVENT_NAME_LEN];
+       char gbuf[MAX_EVENT_NAME_LEN];
        unsigned int flags = TPARG_FL_KERNEL;
 
        switch (argv[0][0]) {
@@ -833,11 +835,13 @@ static int __trace_kprobe_create(int argc, const char *argv[])
 
        trace_probe_log_set_index(0);
        if (event) {
-               ret = traceprobe_parse_event_name(&event, &group, buf,
+               ret = traceprobe_parse_event_name(&event, &group, gbuf,
                                                  event - argv[0]);
                if (ret)
                        goto parse_error;
-       } else {
+       }
+
+       if (!event) {
                /* Make a new event name */
                if (symbol)
                        snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_%ld",

diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c
index 80863c6..850a88a 100644 (file)
--- a/kernel/trace/trace_probe.c
+++ b/kernel/trace/trace_probe.c
@@ -257,6 +257,10 @@ int traceprobe_parse_event_name(const char **pevent, const char **pgroup,
        }
        len = strlen(event);
        if (len == 0) {
+               if (slash) {
+                       *pevent = NULL;
+                       return 0;
+               }
                trace_probe_log_err(offset, NO_EVENT_NAME);
                return -EINVAL;
        } else if (len > MAX_EVENT_NAME_LEN) {

diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
index c3dc4f8..a3fec28 100644 (file)
--- a/kernel/trace/trace_uprobe.c
+++ b/kernel/trace/trace_uprobe.c
@@ -312,7 +312,8 @@ static bool trace_uprobe_match(const char *system, const char *event,
 {
        struct trace_uprobe *tu = to_trace_uprobe(ev);
 
-       return strcmp(trace_probe_name(&tu->tp), event) == 0 &&
+       return (event[0] == '\0' ||
+               strcmp(trace_probe_name(&tu->tp), event) == 0) &&
           (!system || strcmp(trace_probe_group_name(&tu->tp), system) == 0) &&
           trace_uprobe_match_command_head(tu, argc, argv);
 }
@@ -532,7 +533,7 @@ end:
 
 /*
  * Argument syntax:
- *  - Add uprobe: p|r[:[GRP/]EVENT] PATH:OFFSET[%return][(REF)] [FETCHARGS]
+ *  - Add uprobe: p|r[:[GRP/][EVENT]] PATH:OFFSET[%return][(REF)] [FETCHARGS]
  */
 static int __trace_uprobe_create(int argc, const char **argv)
 {
@@ -540,6 +541,7 @@ static int __trace_uprobe_create(int argc, const char **argv)
        const char *event = NULL, *group = UPROBE_EVENT_SYSTEM;
        char *arg, *filename, *rctr, *rctr_end, *tmp;
        char buf[MAX_EVENT_NAME_LEN];
+       char gbuf[MAX_EVENT_NAME_LEN];
        enum probe_print_type ptype;
        struct path path;
        unsigned long offset, ref_ctr_offset;
@@ -644,11 +646,13 @@ static int __trace_uprobe_create(int argc, const char **argv)
        /* setup a probe */
        trace_probe_log_set_index(0);
        if (event) {
-               ret = traceprobe_parse_event_name(&event, &group, buf,
+               ret = traceprobe_parse_event_name(&event, &group, gbuf,
                                                  event - argv[0]);
                if (ret)
                        goto fail_address_parse;
-       } else {
+       }
+
+       if (!event) {
                char *tail;
                char *ptr;