[tip:tracing/core] tracing/syscalls: Add filtering support

From: tip-bot for Li Zefan
Date: Wed Aug 19 2009 - 09:32:47 EST

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Commit-ID: 540b7b8d65575c80162f2a0f38e1d313c92a6042
Gitweb: http://git.kernel.org/tip/540b7b8d65575c80162f2a0f38e1d313c92a6042
Author: Li Zefan <lizf@xxxxxxxxxxxxxx>
AuthorDate: Wed, 19 Aug 2009 15:54:51 +0800
Committer: Ingo Molnar <mingo@xxxxxxx>
CommitDate: Wed, 19 Aug 2009 15:02:24 +0200

tracing/syscalls: Add filtering support

Add filtering support for syscall events:

# echo 'mode == 0666' > events/syscalls/sys_enter_open
# echo 'ret == 0' > events/syscalls/sys_exit_open
# echo 1 > events/syscalls/sys_enter_open
# echo 1 > events/syscalls/sys_exit_open
# cat trace
...
modprobe-3084 [001] 117.463140: sys_open(filename: 917d3e8, flags: 0, mode: 1b6)
modprobe-3084 [001] 117.463176: sys_open -> 0x0
less-3086 [001] 117.510455: sys_open(filename: 9c6bdb8, flags: 8000, mode: 1b6)
sendmail-2574 [001] 122.145840: sys_open(filename: b807a365, flags: 0, mode: 1b6)
...

Signed-off-by: Li Zefan <lizf@xxxxxxxxxxxxxx>
Cc: Jason Baron <jbaron@xxxxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx>
LKML-Reference: <4A8BAFCB.1040006@xxxxxxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>

---
include/linux/ftrace_event.h | 5 ++-
include/linux/syscalls.h | 16 +++++++++----
include/trace/syscall.h | 7 +++++
kernel/trace/trace_events.c | 5 ++-
kernel/trace/trace_syscalls.c | 51 +++++++++++++++++++++++++++++++++++++---
5 files changed, 71 insertions(+), 13 deletions(-)

diff --git a/include/linux/ftrace_event.h b/include/linux/ftrace_event.h
index 427cbae..df5b085 100644
--- a/include/linux/ftrace_event.h
+++ b/include/linux/ftrace_event.h
@@ -140,8 +140,9 @@ extern int filter_current_check_discard(struct ftrace_event_call *call,
void *rec,
struct ring_buffer_event *event);

-extern int trace_define_field(struct ftrace_event_call *call, char *type,
- char *name, int offset, int size, int is_signed);
+extern int trace_define_field(struct ftrace_event_call *call,
+ const char *type, const char *name,
+ int offset, int size, int is_signed);
extern int trace_define_common_fields(struct ftrace_event_call *call);

#define is_signed_type(type) (((type)(-1)) < 0)
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 8d57f77..f124c89 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -190,6 +190,7 @@ static void prof_sysexit_disable_##sname(struct ftrace_event_call *event_call) \
.event = &event_syscall_enter, \
.raw_init = init_enter_##sname, \
.show_format = syscall_enter_format, \
+ .define_fields = syscall_enter_define_fields, \
.regfunc = reg_event_syscall_enter, \
.unregfunc = unreg_event_syscall_enter, \
.data = "sys"#sname, \
@@ -226,6 +227,7 @@ static void prof_sysexit_disable_##sname(struct ftrace_event_call *event_call) \
.event = &event_syscall_exit, \
.raw_init = init_exit_##sname, \
.show_format = syscall_exit_format, \
+ .define_fields = syscall_exit_define_fields, \
.regfunc = reg_event_syscall_exit, \
.unregfunc = unreg_event_syscall_exit, \
.data = "sys"#sname, \
@@ -233,6 +235,8 @@ static void prof_sysexit_disable_##sname(struct ftrace_event_call *event_call) \
}

#define SYSCALL_METADATA(sname, nb) \
+ SYSCALL_TRACE_ENTER_EVENT(sname); \
+ SYSCALL_TRACE_EXIT_EVENT(sname); \
static const struct syscall_metadata __used \
__attribute__((__aligned__(4))) \
__attribute__((section("__syscalls_metadata"))) \
@@ -241,20 +245,22 @@ static void prof_sysexit_disable_##sname(struct ftrace_event_call *event_call) \
.nb_args = nb, \
.types = types_##sname, \
.args = args_##sname, \
- }; \
- SYSCALL_TRACE_ENTER_EVENT(sname); \
- SYSCALL_TRACE_EXIT_EVENT(sname);
+ .enter_event = &event_enter_##sname, \
+ .exit_event = &event_exit_##sname, \
+ };

#define SYSCALL_DEFINE0(sname) \
+ SYSCALL_TRACE_ENTER_EVENT(_##sname); \
+ SYSCALL_TRACE_EXIT_EVENT(_##sname); \
static const struct syscall_metadata __used \
__attribute__((__aligned__(4))) \
__attribute__((section("__syscalls_metadata"))) \
__syscall_meta_##sname = { \
.name = "sys_"#sname, \
.nb_args = 0, \
+ .enter_event = &event_enter__##sname, \
+ .exit_event = &event_exit__##sname, \
}; \
- SYSCALL_TRACE_ENTER_EVENT(_##sname); \
- SYSCALL_TRACE_EXIT_EVENT(_##sname); \
asmlinkage long sys_##sname(void)
#else
#define SYSCALL_DEFINE0(name) asmlinkage long sys_##name(void)
diff --git a/include/trace/syscall.h b/include/trace/syscall.h
index 5ce85d7..9661dd4 100644
--- a/include/trace/syscall.h
+++ b/include/trace/syscall.h
@@ -34,6 +34,8 @@ DECLARE_TRACE_WITH_CALLBACK(syscall_exit,
* @args: list of args as strings (args[i] matches types[i])
* @enter_id: associated ftrace enter event id
* @exit_id: associated ftrace exit event id
+ * @enter_event: associated syscall_enter trace event
+ * @exit_event: associated syscall_exit trace event
*/
struct syscall_metadata {
const char *name;
@@ -42,6 +44,9 @@ struct syscall_metadata {
const char **args;
int enter_id;
int exit_id;
+
+ struct ftrace_event_call *enter_event;
+ struct ftrace_event_call *exit_event;
};

#ifdef CONFIG_FTRACE_SYSCALLS
@@ -59,6 +64,8 @@ extern int syscall_enter_format(struct ftrace_event_call *call,
struct trace_seq *s);
extern int syscall_exit_format(struct ftrace_event_call *call,
struct trace_seq *s);
+extern int syscall_enter_define_fields(struct ftrace_event_call *call);
+extern int syscall_exit_define_fields(struct ftrace_event_call *call);
enum print_line_t print_syscall_enter(struct trace_iterator *iter, int flags);
enum print_line_t print_syscall_exit(struct trace_iterator *iter, int flags);
#endif
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 9c7ecfb..79d3520 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -27,8 +27,8 @@ DEFINE_MUTEX(event_mutex);

LIST_HEAD(ftrace_events);

-int trace_define_field(struct ftrace_event_call *call, char *type,
- char *name, int offset, int size, int is_signed)
+int trace_define_field(struct ftrace_event_call *call, const char *type,
+ const char *name, int offset, int size, int is_signed)
{
struct ftrace_event_field *field;

@@ -83,6 +83,7 @@ int trace_define_common_fields(struct ftrace_event_call *call)

return ret;
}
+EXPORT_SYMBOL_GPL(trace_define_common_fields);

#ifdef CONFIG_MODULES

diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c
index 7336b6c..28e4dae 100644
--- a/kernel/trace/trace_syscalls.c
+++ b/kernel/trace/trace_syscalls.c
@@ -165,6 +165,49 @@ int syscall_exit_format(struct ftrace_event_call *call, struct trace_seq *s)
return trace_seq_printf(s, "\nprint fmt: \"0x%%lx\", REC->ret\n");
}

+int syscall_enter_define_fields(struct ftrace_event_call *call)
+{
+ struct syscall_trace_enter trace;
+ struct syscall_metadata *meta;
+ int ret;
+ int nr;
+ int i;
+ int offset = offsetof(typeof(trace), args);
+
+ nr = syscall_name_to_nr(call->data);
+ meta = syscall_nr_to_meta(nr);
+
+ if (!meta)
+ return 0;
+
+ ret = trace_define_common_fields(call);
+ if (ret)
+ return ret;
+
+ for (i = 0; i < meta->nb_args; i++) {
+ ret = trace_define_field(call, meta->types[i],
+ meta->args[i], offset,
+ sizeof(unsigned long), 0);
+ offset += sizeof(unsigned long);
+ }
+
+ return ret;
+}
+
+int syscall_exit_define_fields(struct ftrace_event_call *call)
+{
+ struct syscall_trace_exit trace;
+ int ret;
+
+ ret = trace_define_common_fields(call);
+ if (ret)
+ return ret;
+
+ ret = trace_define_field(call, SYSCALL_FIELD(unsigned long, ret), 0);
+
+ return ret;
+}
+
void ftrace_syscall_enter(struct pt_regs *regs, long id)
{
struct syscall_trace_enter *entry;
@@ -192,8 +235,8 @@ void ftrace_syscall_enter(struct pt_regs *regs, long id)
entry->nr = syscall_nr;
syscall_get_arguments(current, regs, 0, sys_data->nb_args, entry->args);

- trace_current_buffer_unlock_commit(event, 0, 0);
- trace_wake_up();
+ if (!filter_current_check_discard(sys_data->enter_event, entry, event))
+ trace_current_buffer_unlock_commit(event, 0, 0);
}

void ftrace_syscall_exit(struct pt_regs *regs, long ret)
@@ -220,8 +263,8 @@ void ftrace_syscall_exit(struct pt_regs *regs, long ret)
entry->nr = syscall_nr;
entry->ret = syscall_get_return_value(current, regs);

- trace_current_buffer_unlock_commit(event, 0, 0);
- trace_wake_up();
+ if (!filter_current_check_discard(sys_data->exit_event, entry, event))
+ trace_current_buffer_unlock_commit(event, 0, 0);
}

int reg_event_syscall_enter(void *ptr)
--
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Next message: tip-bot for Peter Zijlstra: "[tip:perfcounters/core] perf tools: Check perf.data owner"
Previous message: tip-bot for Li Zefan: "[tip:tracing/core] tracing/events: Add trace_define_common_fields()"
In reply to: Li Zefan: "[PATCH 5/5] tracing/syscalls: Add filtering support"
Next in thread: Frederic Weisbecker: "Re: [PATCH 0/5] tracing/syscalls: Add filtering support"
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