Make it possible to specify a trace event filter from the
kernel command line.
Example:
trace_event=syscalls:sys_enter_clock_nanosleep:filter:which_clock==0
Signed-off-by: Thomas Weißschuh <[email protected]>
---
Documentation/admin-guide/kernel-parameters.txt | 9 +++++++--
Documentation/trace/events.rst | 5 +++++
include/linux/trace_events.h | 2 +-
kernel/trace/trace.h | 3 ++-
kernel/trace/trace_boot.c | 2 +-
kernel/trace/trace_events.c | 27 +++++++++++++++++--------
kernel/trace/trace_events_test.c | 26 +++++++++++++++++++++---
7 files changed, 58 insertions(+), 16 deletions(-)
diff --git a/Documentation/admin-guide/kernel-parameters.txt
b/Documentation/admin-guide/kernel-parameters.txt
index 68647ff4bdd2..63347a986706 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -7769,8 +7769,13 @@ Kernel parameters
trace_event=:mod:<module>
The value before :mod: will only enable specific events
- that are part of the module. See the above mentioned
- document for more information.
+ that are part of the module.
+
+ To apply a filter, use the :filter: keyword:
+
+ trace_event=...:filter:<filter>
+
+ See the above mentioned document for more information.
trace_instance=[instance-info]
[FTRACE] Create a ring buffer instance early in boot up.
diff --git a/Documentation/trace/events.rst b/Documentation/trace/events.rst
index 581f2260614b..6ce53372acbc 100644
--- a/Documentation/trace/events.rst
+++ b/Documentation/trace/events.rst
@@ -118,6 +118,11 @@ In order to facilitate early boot debugging, use boot
option::
event-list is a comma separated list of events. See section 2.1 for event
format.
+The boot option also supports the ``:filter:`` keyword to apply a filter.
+The ``:filter:`` keyword needs to be at the end of the event specification::
+
+ <system>:<event>:mod:<module>:filter:<filter>
+
3. Defining an event-enabled tracepoint
=======================================
diff --git a/include/linux/trace_events.h b/include/linux/trace_events.h
index af46614bc75d..c1f6bb94f483 100644
--- a/include/linux/trace_events.h
+++ b/include/linux/trace_events.h
@@ -882,7 +882,7 @@ extern int trace_add_event_call(struct trace_event_call
*call);
extern int trace_remove_event_call(struct trace_event_call *call);
extern int trace_event_get_offsets(struct trace_event_call *call);
-int ftrace_set_clr_event(struct trace_array *tr, const char *buf, int set);
+int ftrace_set_clr_event(struct trace_array *tr, const char *buf, int set,
bool handle_filter);
int trace_set_clr_event(const char *system, const char *event, int set);
int trace_array_set_clr_event(struct trace_array *tr, const char *system,
const char *event, bool enable);
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 35f619a1655e..2ec212d90192 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -2508,5 +2508,6 @@ static inline int rv_init_interface(void)
#endif /* _LINUX_KERNEL_TRACE_H */
#if IS_ENABLED(CONFIG_KUNIT)
-void ftrace_parse_event_string(char *buf, char **match, char **sub, char
**event, char **mod);
+void ftrace_parse_event_string(char *buf, char **match, char **sub, char
**event, char **mod,
+ bool handle_filter, char **filter);
#endif
diff --git a/kernel/trace/trace_boot.c b/kernel/trace/trace_boot.c
index 5da0a8bbb110..6ba70dac1f06 100644
--- a/kernel/trace/trace_boot.c
+++ b/kernel/trace/trace_boot.c
@@ -94,7 +94,7 @@ trace_boot_enable_events(struct trace_array *tr, struct
xbc_node *node)
continue;
}
- if (ftrace_set_clr_event(tr, buf, 1) < 0)
+ if (ftrace_set_clr_event(tr, buf, 1, false) < 0)
pr_err("Failed to enable event: %s\n", p);
}
}
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index f8881a9d3c7a..2e2815d95c56 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -1455,10 +1455,21 @@ static int __ftrace_set_clr_event(struct trace_array
*tr, const char *match,
}
VISIBLE_IF_KUNIT void
-ftrace_parse_event_string(char *buf, char **match, char **sub, char **event,
char **mod)
+ftrace_parse_event_string(char *buf, char **match, char **sub, char **event,
char **mod,
+ bool handle_filter, char **filter)
{
*event = NULL;
*sub = NULL;
+ *filter = NULL;
+
+ /* event filters can be appended with :filter:<filter> */
+ if (handle_filter) {
+ *filter = strstr(buf, ":filter:");
+ if (*filter) {
+ **filter = '\0';
+ *filter += 8;
+ }
+ }
/* Modules events can be appended with :mod:<module> */
*mod = strstr(buf, ":mod:");
@@ -1498,9 +1509,9 @@ ftrace_parse_event_string(char *buf, char **match, char
**sub, char **event, cha
}
EXPORT_SYMBOL_IF_KUNIT(ftrace_parse_event_string);
-int ftrace_set_clr_event(struct trace_array *tr, const char *arg_buf, int set)
+int ftrace_set_clr_event(struct trace_array *tr, const char *arg_buf, int set,
bool handle_filter)
{
- char *event, *sub, *match, *mod;
+ char *event, *sub, *match, *mod, *filter;
if (!tr)
return -ENOENT;
@@ -1509,9 +1520,9 @@ int ftrace_set_clr_event(struct trace_array *tr, const
char *arg_buf, int set)
if (!dupped_buf)
return -ENOMEM;
- ftrace_parse_event_string(dupped_buf, &match, &sub, &event, &mod);
+ ftrace_parse_event_string(dupped_buf, &match, &sub, &event, &mod,
handle_filter, &filter);
- return __ftrace_set_clr_event(tr, match, sub, event, set, mod, NULL);
+ return __ftrace_set_clr_event(tr, match, sub, event, set, mod, filter);
}
/**
@@ -1593,7 +1604,7 @@ ftrace_event_write(struct file *file, const char __user
*ubuf,
if (*parser.buffer == '!')
set = 0;
- ret = ftrace_set_clr_event(tr, parser.buffer + !set, set);
+ ret = ftrace_set_clr_event(tr, parser.buffer + !set, set,
false);
if (ret)
goto out_put;
}
@@ -4842,10 +4853,10 @@ static __init void __early_set_events(struct
trace_array *tr, char *buf, bool en
while ((token = strsep(&buf, ","))) {
if (*token) {
if (enable) {
- if (ftrace_set_clr_event(tr, token, 1))
+ if (ftrace_set_clr_event(tr, token, 1, true))
pr_warn("Failed to enable trace event:
%s\n", token);
} else {
- ftrace_set_clr_event(tr, token, 0);
+ ftrace_set_clr_event(tr, token, 0, true);
}
}
diff --git a/kernel/trace/trace_events_test.c b/kernel/trace/trace_events_test.c
index 515d2e668c31..4a2d77fa0f58 100644
--- a/kernel/trace/trace_events_test.c
+++ b/kernel/trace/trace_events_test.c
@@ -8,7 +8,7 @@
struct parse_event_string_test_case {
const char *input;
- const char *match, *sub, *event, *mod;
+ const char *match, *sub, *event, *mod, *filter;
};
static const struct parse_event_string_test_case
parse_event_string_test_cases[] = {
@@ -37,6 +37,12 @@ static const struct parse_event_string_test_case
parse_event_string_test_cases[]
.sub = "sub",
.event = "event",
},
+ {
+ "sub:event:filter:filter",
+ .sub = "sub",
+ .event = "event",
+ .filter = "filter",
+ },
{
"match",
.match = "match",
@@ -51,6 +57,19 @@ static const struct parse_event_string_test_case
parse_event_string_test_cases[]
.event = "event",
.mod = "module",
},
+ {
+ "sub:event:mod:module:filter:filter",
+ .sub = "sub",
+ .event = "event",
+ .mod = "module",
+ .filter = "filter",
+ },
+ {
+ "sub:event:mod:module:filter:unexpected-filter",
+ .sub = "sub",
+ .event = "event",
+ .mod = "module:filter:unexpected-filter",
+ },
};
static void
@@ -72,18 +91,19 @@ KUNIT_ARRAY_PARAM(parse_event_string,
parse_event_string_test_cases, parse_event
static void parse_event_string(struct kunit *test)
{
const struct parse_event_string_test_case *params = test->param_value;
- char *input, *match, *sub, *event, *mod;
+ char *input, *match, *sub, *event, *mod, *filter;
input = kunit_kstrdup(test, params->input, GFP_KERNEL);
if (!input)
kunit_skip(test, "ENOMEM");
- ftrace_parse_event_string(input, &match, &sub, &event, &mod);
+ ftrace_parse_event_string(input, &match, &sub, &event, &mod,
params->filter, &filter);
EXPECT_NULL_OR_STR_EQ(test, match, params->match);
EXPECT_NULL_OR_STR_EQ(test, sub, params->sub);
EXPECT_NULL_OR_STR_EQ(test, event, params->event);
EXPECT_NULL_OR_STR_EQ(test, mod, params->mod);
+ EXPECT_NULL_OR_STR_EQ(test, filter, params->filter);
}
static struct kunit_case trace_events_test_cases[] = {
--
2.55.0
