trace-kprobe: Support delete probe syntax

Support delete probe syntax. The syntax is "-:[group/]event".

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Jim Keniston <jkenisto@us.ibm.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Frank Ch. Eigler <fche@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: K.Prasad <prasad@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: systemtap <systemtap@sources.redhat.com>
Cc: DLE <dle-develop@lists.sourceforge.net>
LKML-Reference: <20091208220316.10142.39192.stgit@dhcp-100-2-132.bos.redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Jim Keniston <jkenisto@us.ibm.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Frank Ch. Eigler <fche@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: K.Prasad <prasad@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 28 insertions, 9 deletions

diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index aff5f80b59b8..bf05fb49a6f3 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -606,23 +606,22 @@ static int create_trace_probe(int argc, char **argv)
          */
         struct trace_probe *tp;
         int i, ret = 0;
-        int is_return = 0;
+        int is_return = 0, is_delete = 0;
         char *symbol = NULL, *event = NULL, *arg = NULL, *group = NULL;
         unsigned long offset = 0;
         void *addr = NULL;
         char buf[MAX_EVENT_NAME_LEN];
 
-        if (argc < 2) {
-                pr_info("Probe point is not specified.\n");
-                return -EINVAL;
-        }
-
+        /* argc must be >= 1 */
         if (argv[0][0] == 'p')
                 is_return = 0;
         else if (argv[0][0] == 'r')
                 is_return = 1;
+        else if (argv[0][0] == '-')
+                is_delete = 1;
         else {
-                pr_info("Probe definition must be started with 'p' or 'r'.\n");
+                pr_info("Probe definition must be started with 'p', 'r' or"
+                        " '-'.\n");
                 return -EINVAL;
         }
 
@@ -642,7 +641,29 @@ static int create_trace_probe(int argc, char **argv)
                         return -EINVAL;
                 }
         }
+        if (!group)
+                group = KPROBE_EVENT_SYSTEM;
 
+        if (is_delete) {
+                if (!event) {
+                        pr_info("Delete command needs an event name.\n");
+                        return -EINVAL;
+                }
+                tp = find_probe_event(event, group);
+                if (!tp) {
+                        pr_info("Event %s/%s doesn't exist.\n", group, event);
+                        return -ENOENT;
+                }
+                /* delete an event */
+                unregister_trace_probe(tp);
+                free_trace_probe(tp);
+                return 0;
+        }
+
+        if (argc < 2) {
+                pr_info("Probe point is not specified.\n");
+                return -EINVAL;
+        }
         if (isdigit(argv[1][0])) {
                 if (is_return) {
                         pr_info("Return probe point must be a symbol.\n");
@@ -671,8 +692,6 @@ static int create_trace_probe(int argc, char **argv)
         argc -= 2; argv += 2;
 
         /* setup a probe */
-        if (!group)
-                group = KPROBE_EVENT_SYSTEM;
         if (!event) {
                 /* Make a new event name */
                 if (symbol)