[PATCH RFC 7/7] tracing: Parse filter from event string
From: Thomas Weißschuh <hidden>
Date: 2026-08-13 14:07:33
Also in:
lkml
Subsystem:
the rest, tracing · Maintainers:
Linus Torvalds, Steven Rostedt, Masami Hiramatsu
Make it possible to specify a trace event filter from the kernel command line. Signed-off-by: Thomas Weißschuh <redacted> --- For the non-RFC patch this should probably be limited to only apply to the cmdline path. --- kernel/trace/trace.h | 3 ++- kernel/trace/trace_events.c | 13 +++++++++---- kernel/trace/trace_events_test.c | 20 +++++++++++++++++--- 3 files changed, 28 insertions(+), 8 deletions(-)
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 6bf4f031efa8..9102bf0a45a9 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h@@ -2507,5 +2507,6 @@ 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, + char **filter); #endif
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index c24929d003dd..d4c46b24c382 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c@@ -1426,10 +1426,12 @@ 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, + char **filter) { *event = NULL; *sub = NULL; + *filter = NULL; /* Modules events can be appended with :mod:<module> */ *mod = strstr(buf, ":mod:");
@@ -1453,6 +1455,9 @@ ftrace_parse_event_string(char *buf, char **match, char **sub, char **event, cha *match = strsep(&buf, ":"); if (buf) { + *filter = buf; + strsep(filter, ":"); + *sub = *match; *event = buf; *match = NULL;
@@ -1471,7 +1476,7 @@ EXPORT_SYMBOL_IF_KUNIT(ftrace_parse_event_string); int ftrace_set_clr_event(struct trace_array *tr, const char *_buf, int set) { - char *event, *sub, *match, *mod; + char *event, *sub, *match, *mod, *filter; if (!tr) return -ENOENT;
@@ -1480,9 +1485,9 @@ int ftrace_set_clr_event(struct trace_array *tr, const char *_buf, int set) if (!buf) return -ENOMEM; - ftrace_parse_event_string(buf, &match, &sub, &event, &mod); + ftrace_parse_event_string(buf, &match, &sub, &event, &mod, &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); } /**
diff --git a/kernel/trace/trace_events_test.c b/kernel/trace/trace_events_test.c
index e090a699b8d5..fd54eb03b58f 100644
--- a/kernel/trace/trace_events_test.c
+++ b/kernel/trace/trace_events_test.c@@ -8,7 +8,7 @@ struct parse_event_test_case { const char *input; - const char *match, *sub, *event, *mod; + const char *match, *sub, *event, *mod, *filter; }; static const struct parse_event_test_case parse_event_test_cases[] = {
@@ -37,6 +37,12 @@ static const struct parse_event_test_case parse_event_test_cases[] = { .sub = "sub", .event = "event", }, + { + "sub:event:filter", + .sub = "sub", + .event = "event", + .filter = "filter", + }, { "match", .match = "match",
@@ -51,6 +57,13 @@ static const struct parse_event_test_case parse_event_test_cases[] = { .event = "event", .mod = "module", }, + { + "sub:event:filter:mod:module", + .sub = "sub", + .event = "event", + .mod = "module", + .filter = "filter", + }, }; static void parse_event_test_desc(const struct parse_event_test_case *params, char *desc)
@@ -71,18 +84,19 @@ KUNIT_ARRAY_PARAM(parse_event, parse_event_test_cases, parse_event_test_desc); static void parse_event(struct kunit *test) { const struct parse_event_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, &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[] = {
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2.55.0