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Date: Wed, 22 May 2013 11:19:17 +0900
From: Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>
To: linux-kernel@...r.kernel.org, Steven Rostedt <rostedt@...dmis.org>
Cc: Srikar Dronamraju <srikar@...ux.vnet.ibm.com>,
Frederic Weisbecker <fweisbec@...il.com>,
yrl.pp-manager.tt@...achi.com, Oleg Nesterov <oleg@...hat.com>,
Ingo Molnar <mingo@...hat.com>,
Tom Zanussi <tom.zanussi@...el.com>
Subject: [PATCH v2 4/5] tracing/kprobes: Allow user to delete kprobe events by
wild cards
Allow user to delete multiple kprobe events by using
wild cards. This makes removing events on a specific
function easy.
e.g.)
# echo p vfs_symlink >> kprobe_events
# echo p vfs_symlink+5 >> kprobe_events
# echo p vfs_read >> kprobe_events
# cat kprobe_events
p:kprobes/p_vfs_symlink_0 vfs_symlink
p:kprobes/p_vfs_symlink_5 vfs_symlink+5
p:kprobes/p_vfs_read_0 vfs_read
# echo -:kprobes/\*vfs_symlink_\* >> kprobe_events
# cat kprobe_events
p:kprobes/p_vfs_read_0 vfs_read
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>
Cc: Steven Rostedt <rostedt@...dmis.org>
Cc: Frederic Weisbecker <fweisbec@...il.com>
Cc: Ingo Molnar <mingo@...hat.com>
---
Documentation/trace/kprobetrace.txt | 19 ++++---
kernel/trace/trace_kprobe.c | 97 +++++++++++++++++++++++++----------
2 files changed, 82 insertions(+), 34 deletions(-)
diff --git a/Documentation/trace/kprobetrace.txt b/Documentation/trace/kprobetrace.txt
index d68ea5f..04f22be 100644
--- a/Documentation/trace/kprobetrace.txt
+++ b/Documentation/trace/kprobetrace.txt
@@ -26,9 +26,9 @@ Synopsis of kprobe_events
r[:[GRP/]EVENT] [MOD:]SYM[+0] [FETCHARGS] : Set a return probe
-:[GRP/]EVENT : Clear a probe
- GRP : Group name. If omitted, use "kprobes" for it.
+ GRP : Group name. If omitted, use "kprobes" for it.(*)
EVENT : Event name. If omitted, the event name is generated
- based on SYM+offs or MEMADDR.
+ based on SYM+offs or MEMADDR.(*)
MOD : Module name which has given SYM.
SYM[+offs] : Symbol+offset where the probe is inserted.
MEMADDR : Address where the probe is inserted.
@@ -39,15 +39,16 @@ Synopsis of kprobe_events
@SYM[+|-offs] : Fetch memory at SYM +|- offs (SYM should be a data symbol)
$stackN : Fetch Nth entry of stack (N >= 0)
$stack : Fetch stack address.
- $retval : Fetch return value.(*)
- +|-offs(FETCHARG) : Fetch memory at FETCHARG +|- offs address.(**)
+ $retval : Fetch return value.(**)
+ +|-offs(FETCHARG) : Fetch memory at FETCHARG +|- offs address.(***)
NAME=FETCHARG : Set NAME as the argument name of FETCHARG.
FETCHARG:TYPE : Set TYPE as the type of FETCHARG. Currently, basic types
(u8/u16/u32/u64/s8/s16/s32/s64), "string" and bitfield
are supported.
- (*) only for return probe.
- (**) this is useful for fetching a field of data structures.
+ (*) both GRP and EVENT accept glob-style wild cards when clearing probes.
+ (**) only for return probe.
+ (***) this is useful for fetching a field of data structures.
Types
-----
@@ -143,7 +144,11 @@ REC->dfd, REC->filename, REC->flags, REC->mode
echo -:myprobe >> kprobe_events
- This clears probe points selectively.
+ This removes a probe points selectively. Since the event name and group
+ name accept wild cards only when removing, you can clear all event as
+ below too.
+
+ echo '-:*/*' >> kprobe_events
Right after definition, each event is disabled by default. For tracing these
events, you need to enable it.
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 9f46e98..b619853 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -171,16 +171,32 @@ static void free_trace_probe(struct trace_probe *tp)
kfree(tp);
}
-static struct trace_probe *find_trace_probe(const char *event,
- const char *group)
+/**
+ * find_trace_probes - find matched trace_probe and return the number of it
+ * @event: event name (glob pattern)
+ * @group: group(subsystem) name (glob pattern)
+ * @buf: the address of an array of trace_probe *
+ * @size: the size of @buf array
+ *
+ * Search trace_probe matched with given name (pattern) and returns
+ * the number of it. If @buf is not NULL, it records the address of
+ * the matched trace_probe on it.
+ */
+static int
+find_trace_probes(const char *event, const char *group,
+ struct trace_probe **buf, int size)
{
struct trace_probe *tp;
+ int count = 0;
list_for_each_entry(tp, &probe_list, list)
- if (strcmp(tp->call.name, event) == 0 &&
- strcmp(tp->call.class->system, group) == 0)
- return tp;
- return NULL;
+ if (strglobmatch(event, tp->call.name) &&
+ strglobmatch(group, tp->call.class->system)) {
+ if (buf && count < size)
+ buf[count] = tp;
+ count++;
+ }
+ return count;
}
static int trace_probe_nr_files(struct trace_probe *tp)
@@ -414,8 +430,9 @@ static int register_trace_probe(struct trace_probe *tp)
mutex_lock(&probe_lock);
/* Delete old (same name) event if exist */
- old_tp = find_trace_probe(tp->call.name, tp->call.class->system);
- if (old_tp) {
+ ret = find_trace_probes(tp->call.name, tp->call.class->system,
+ &old_tp, 1);
+ if (ret) {
ret = unregister_trace_probe(old_tp);
if (ret < 0)
goto end;
@@ -475,6 +492,49 @@ static struct notifier_block trace_probe_module_nb = {
.priority = 1 /* Invoked after kprobe module callback */
};
+static int delete_trace_probe(const char *event, const char *group)
+{
+ struct trace_probe **tps;
+ int nr_tps, i, ret = 0;
+
+ if (!event) {
+ pr_info("Delete command needs an event name.\n");
+ return -EINVAL;
+ }
+
+ mutex_lock(&probe_lock);
+
+ nr_tps = find_trace_probes(event, group, NULL, 0);
+ if (nr_tps == 0) {
+ pr_info("Event %s/%s doesn't matched.\n", group, event);
+ ret = -ENOENT;
+ goto out_unlock;
+ }
+
+ tps = kzalloc(nr_tps * sizeof(*tps), GFP_KERNEL);
+ if (!tps) {
+ ret = -ENOMEM;
+ goto out_unlock;
+ }
+
+ find_trace_probes(event, group, tps, nr_tps);
+
+ for (i = 0; i < nr_tps; i++) {
+ ret = unregister_trace_probe(tps[i]);
+ if (ret < 0) {
+ pr_info("Failed to delete event: %d\n", ret);
+ continue; /* Greedy cleanup */
+ }
+ free_trace_probe(tps[i]);
+ }
+ ret = 0;
+ kfree(tps);
+
+ out_unlock:
+ mutex_unlock(&probe_lock);
+ return ret;
+}
+
static int create_trace_probe(int argc, char **argv)
{
/*
@@ -536,25 +596,8 @@ static int create_trace_probe(int argc, char **argv)
if (!group)
group = KPROBE_EVENT_SYSTEM;
- if (is_delete) {
- if (!event) {
- pr_info("Delete command needs an event name.\n");
- return -EINVAL;
- }
- mutex_lock(&probe_lock);
- tp = find_trace_probe(event, group);
- if (!tp) {
- mutex_unlock(&probe_lock);
- pr_info("Event %s/%s doesn't exist.\n", group, event);
- return -ENOENT;
- }
- /* delete an event */
- ret = unregister_trace_probe(tp);
- if (ret == 0)
- free_trace_probe(tp);
- mutex_unlock(&probe_lock);
- return ret;
- }
+ if (is_delete)
+ return delete_trace_probe(event, group);
if (argc < 2) {
pr_info("Probe point is not specified.\n");
--
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