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>

diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index aff5f80..bf05fb4 100644 (file)
--- 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)