* [PATCH v13 1/4] trace: Add trace any kernel object
2022-06-26 2:56 [PATCH v13 0/4] trace: Introduce objtrace trigger to trace the kernel object Jeff Xie
@ 2022-06-26 2:56 ` Jeff Xie
2022-06-26 2:56 ` [PATCH v13 2/4] trace/objtrace: Get the value of the object Jeff Xie
` (2 subsequent siblings)
3 siblings, 0 replies; 12+ messages in thread
From: Jeff Xie @ 2022-06-26 2:56 UTC (permalink / raw)
To: rostedt
Cc: mingo, mhiramat, zanussi, linux-kernel, linux-kselftest, shuah,
linux-doc, corbet, chensong_2000, Jeff Xie
Introduce objtrace trigger to get the call flow by tracing any kernel
object in the function parameter.
The objtrace trigger makes a list of the target object address from
the given event parameter, and records all kernel function calls
which has the object address in its parameter.
Syntax:
objtrace:add:obj[:count][if <filter>]
Usage:
# echo 'p bio_add_page arg1=$arg1' > kprobe_events
# cd events/kprobes/p_bio_add_page_0
# echo 'objtrace:add:arg1:1 if comm == "cat"' > ./trigger
# cat /test.txt
Signed-off-by: Jeff Xie <xiehuan09@gmail.com>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
---
include/linux/trace_events.h | 1 +
kernel/trace/Kconfig | 10 +
kernel/trace/Makefile | 1 +
kernel/trace/trace.c | 11 +
kernel/trace/trace.h | 21 ++
kernel/trace/trace_entries.h | 17 ++
kernel/trace/trace_events_trigger.c | 5 +-
kernel/trace/trace_object.c | 450 ++++++++++++++++++++++++++++
kernel/trace/trace_output.c | 40 +++
9 files changed, 554 insertions(+), 2 deletions(-)
create mode 100644 kernel/trace/trace_object.c
diff --git a/include/linux/trace_events.h b/include/linux/trace_events.h
index e6e95a9f07a5..f3645166b724 100644
--- a/include/linux/trace_events.h
+++ b/include/linux/trace_events.h
@@ -693,6 +693,7 @@ enum event_trigger_type {
ETT_EVENT_HIST = (1 << 4),
ETT_HIST_ENABLE = (1 << 5),
ETT_EVENT_EPROBE = (1 << 6),
+ ETT_TRACE_OBJECT = (1 << 7),
};
extern int filter_match_preds(struct event_filter *filter, void *rec);
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index 2c43e327a619..30c34d43dc3f 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -276,6 +276,16 @@ config FUNCTION_PROFILER
If in doubt, say N.
+config TRACE_OBJECT
+ bool "Trace kernel object in function parameter"
+ depends on FUNCTION_TRACER
+ depends on HAVE_FUNCTION_ARG_ACCESS_API
+ select TRACING
+ default y
+ help
+ You can trace the kernel object in the kernel function parameter.
+ The kernel object is dynamically specified via event trigger.
+
config STACK_TRACER
bool "Trace max stack"
depends on HAVE_FUNCTION_TRACER
diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile
index 0d261774d6f3..90ecc3c6c9d5 100644
--- a/kernel/trace/Makefile
+++ b/kernel/trace/Makefile
@@ -71,6 +71,7 @@ obj-$(CONFIG_FUNCTION_GRAPH_TRACER) += trace_functions_graph.o
obj-$(CONFIG_TRACE_BRANCH_PROFILING) += trace_branch.o
obj-$(CONFIG_BLK_DEV_IO_TRACE) += blktrace.o
obj-$(CONFIG_FUNCTION_GRAPH_TRACER) += fgraph.o
+obj-$(CONFIG_TRACE_OBJECT) += trace_object.o
ifeq ($(CONFIG_BLOCK),y)
obj-$(CONFIG_EVENT_TRACING) += blktrace.o
endif
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index f400800bc910..7074ad8bc1a0 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -5627,6 +5627,9 @@ static const char readme_msg[] =
"\t enable_hist:<system>:<event>\n"
"\t disable_hist:<system>:<event>\n"
#endif
+#ifdef CONFIG_TRACE_OBJECT
+ "\t objtrace:add:obj[:count][if <filter>]\n"
+#endif
#ifdef CONFIG_STACKTRACE
"\t\t stacktrace\n"
#endif
@@ -9272,6 +9275,9 @@ static struct trace_array *trace_array_create(const char *name)
if (ftrace_allocate_ftrace_ops(tr) < 0)
goto out_free_tr;
+ if (allocate_objtrace_data(tr) < 0)
+ goto out_free_tr;
+
ftrace_init_trace_array(tr);
init_trace_flags_index(tr);
@@ -9291,6 +9297,7 @@ static struct trace_array *trace_array_create(const char *name)
out_free_tr:
ftrace_free_ftrace_ops(tr);
+ free_objtrace_data(tr);
free_trace_buffers(tr);
free_cpumask_var(tr->tracing_cpumask);
kfree(tr->name);
@@ -9384,6 +9391,7 @@ static int __remove_instance(struct trace_array *tr)
event_trace_del_tracer(tr);
ftrace_clear_pids(tr);
ftrace_destroy_function_files(tr);
+ free_objtrace_data(tr);
tracefs_remove(tr->dir);
free_percpu(tr->last_func_repeats);
free_trace_buffers(tr);
@@ -10118,6 +10126,9 @@ __init static int tracer_alloc_buffers(void)
goto out_free_savedcmd;
}
+ if (allocate_objtrace_data(&global_trace))
+ goto out_free_savedcmd;
+
if (global_trace.buffer_disabled)
tracing_off();
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index ff816fb41e48..18220b659555 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -54,6 +54,7 @@ enum trace_type {
TRACE_TIMERLAT,
TRACE_RAW_DATA,
TRACE_FUNC_REPEATS,
+ TRACE_OBJECT,
__TRACE_LAST_TYPE,
};
@@ -363,6 +364,9 @@ struct trace_array {
cpumask_var_t tracing_cpumask; /* only trace on set CPUs */
int ref;
int trace_ref;
+#ifdef CONFIG_TRACE_OBJECT
+ struct objtrace_data *obj_data;
+#endif
#ifdef CONFIG_FUNCTION_TRACER
struct ftrace_ops *ops;
struct trace_pid_list __rcu *function_pids;
@@ -471,6 +475,7 @@ extern void __ftrace_bad_type(void);
TRACE_GRAPH_RET); \
IF_ASSIGN(var, ent, struct func_repeats_entry, \
TRACE_FUNC_REPEATS); \
+ IF_ASSIGN(var, ent, struct trace_object_entry, TRACE_OBJECT);\
__ftrace_bad_type(); \
} while (0)
@@ -1536,6 +1541,16 @@ static inline int register_trigger_hist_cmd(void) { return 0; }
static inline int register_trigger_hist_enable_disable_cmds(void) { return 0; }
#endif
+#ifdef CONFIG_TRACE_OBJECT
+extern int register_trigger_object_cmd(void);
+extern int allocate_objtrace_data(struct trace_array *tr);
+extern void free_objtrace_data(struct trace_array *tr);
+#else
+static inline int register_trigger_object_cmd(void) { return 0; }
+static inline int allocate_objtrace_data(struct trace_array *tr) { return 0; }
+static inline void free_objtrace_data(struct trace_array *tr) { };
+#endif
+
extern int register_trigger_cmds(void);
extern void clear_event_triggers(struct trace_array *tr);
@@ -1611,6 +1626,12 @@ extern bool event_trigger_check_remove(const char *glob);
extern bool event_trigger_empty_param(const char *param);
extern int event_trigger_separate_filter(char *param_and_filter, char **param,
char **filter, bool param_required);
+extern int register_trigger(char *glob,
+ struct event_trigger_data *data,
+ struct trace_event_file *file);
+extern void unregister_trigger(char *glob,
+ struct event_trigger_data *test,
+ struct trace_event_file *file);
extern struct event_trigger_data *
event_trigger_alloc(struct event_command *cmd_ops,
char *cmd,
diff --git a/kernel/trace/trace_entries.h b/kernel/trace/trace_entries.h
index cd41e863b51c..bb120d9498a9 100644
--- a/kernel/trace/trace_entries.h
+++ b/kernel/trace/trace_entries.h
@@ -401,3 +401,20 @@ FTRACE_ENTRY(timerlat, timerlat_entry,
__entry->context,
__entry->timer_latency)
);
+
+/*
+ * trace object entry:
+ */
+FTRACE_ENTRY(object, trace_object_entry,
+
+ TRACE_OBJECT,
+
+ F_STRUCT(
+ __field( unsigned long, ip )
+ __field( unsigned long, parent_ip )
+ __field( unsigned long, object )
+ ),
+
+ F_printk(" %ps <-- %ps object:%lx\n",
+ (void *)__entry->ip, (void *)__entry->parent_ip, __entry->object)
+);
diff --git a/kernel/trace/trace_events_trigger.c b/kernel/trace/trace_events_trigger.c
index cb866c3141af..8bad4eb3b997 100644
--- a/kernel/trace/trace_events_trigger.c
+++ b/kernel/trace/trace_events_trigger.c
@@ -560,7 +560,7 @@ void update_cond_flag(struct trace_event_file *file)
*
* Return: 0 on success, errno otherwise
*/
-static int register_trigger(char *glob,
+int register_trigger(char *glob,
struct event_trigger_data *data,
struct trace_event_file *file)
{
@@ -605,7 +605,7 @@ static int register_trigger(char *glob,
* Usually used directly as the @unreg method in event command
* implementations.
*/
-static void unregister_trigger(char *glob,
+void unregister_trigger(char *glob,
struct event_trigger_data *test,
struct trace_event_file *file)
{
@@ -1976,6 +1976,7 @@ __init int register_trigger_cmds(void)
register_trigger_enable_disable_cmds();
register_trigger_hist_enable_disable_cmds();
register_trigger_hist_cmd();
+ register_trigger_object_cmd();
return 0;
}
diff --git a/kernel/trace/trace_object.c b/kernel/trace/trace_object.c
new file mode 100644
index 000000000000..19ec4b1c0186
--- /dev/null
+++ b/kernel/trace/trace_object.c
@@ -0,0 +1,450 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * trace the kernel object in the kernel function parameter
+ * Copyright (C) 2021 Jeff Xie <xiehuan09@gmail.com>
+ */
+
+#define pr_fmt(fmt) "trace_object: " fmt
+
+#include "trace_output.h"
+
+#define MAX_TRACED_OBJECT 5
+#define OBJTRACE_CMD_LEN 16
+#define OBJTRACE_CMD_ADD "add"
+static LIST_HEAD(obj_data_head);
+static const int max_args_num = 6;
+static void exit_trace_object(struct trace_array *tr);
+static int init_trace_object(struct trace_array *tr);
+
+struct object_instance {
+ void *obj;
+ struct trace_array *tr;
+};
+
+/* objtrace private data */
+struct objtrace_trigger_data {
+ struct ftrace_event_field *field;
+ char objtrace_cmd[OBJTRACE_CMD_LEN];
+ struct trace_array *tr;
+};
+
+/* objtrace data with fops and objtrace_instances */
+struct objtrace_data {
+ struct list_head head;
+ struct trace_array *tr;
+ struct ftrace_ops fops;
+ int num_traced_obj;
+ struct object_instance traced_obj[MAX_TRACED_OBJECT];
+ raw_spinlock_t obj_data_lock;
+};
+
+static struct objtrace_data *get_obj_data(struct trace_array *tr)
+{
+ struct objtrace_data *obj_data = NULL;
+
+ list_for_each_entry(obj_data, &obj_data_head, head) {
+ if (obj_data->tr == tr)
+ break;
+ }
+ return obj_data;
+}
+
+static bool object_exist(void *obj, struct trace_array *tr)
+{
+ int i, max;
+ struct objtrace_data *obj_data;
+
+ obj_data = get_obj_data(tr);
+ if (!obj_data)
+ return false;
+
+ max = READ_ONCE(obj_data->num_traced_obj);
+ smp_rmb();
+ for (i = 0; i < max; i++) {
+ if (obj_data->traced_obj[i].obj == obj)
+ return true;
+ }
+ return false;
+}
+
+static bool object_empty(struct trace_array *tr)
+{
+ struct objtrace_data *obj_data;
+
+ obj_data = get_obj_data(tr);
+ if (!obj_data)
+ return false;
+
+ return !READ_ONCE(obj_data->num_traced_obj);
+}
+
+static void set_trace_object(void *obj, struct trace_array *tr)
+{
+ unsigned long flags;
+ struct object_instance *obj_ins;
+ struct objtrace_data *obj_data;
+
+ if (in_nmi())
+ return;
+
+ if (!obj && object_exist(obj, tr))
+ return;
+
+ obj_data = get_obj_data(tr);
+ if (!obj_data)
+ return;
+
+ /* only this place has write operations */
+ raw_spin_lock_irqsave(&obj_data->obj_data_lock, flags);
+ if (READ_ONCE(obj_data->num_traced_obj) == MAX_TRACED_OBJECT) {
+ trace_array_printk_buf(tr->array_buffer.buffer, _THIS_IP_,
+ "object_pool is full, can't trace object:0x%px\n", obj);
+ goto out;
+ }
+ obj_ins = &obj_data->traced_obj[READ_ONCE(obj_data->num_traced_obj)];
+ obj_ins->obj = obj;
+ obj_ins->tr = tr;
+ /* make sure the num_traced_obj update always appears after traced_obj update */
+ smp_wmb();
+ obj_data->num_traced_obj++;
+out:
+ raw_spin_unlock_irqrestore(&obj_data->obj_data_lock, flags);
+}
+
+static void submit_trace_object(unsigned long ip, unsigned long parent_ip,
+ unsigned long object, struct trace_array *tr)
+{
+
+ struct trace_buffer *buffer = tr->array_buffer.buffer;
+ struct ring_buffer_event *event;
+ struct trace_object_entry *entry;
+ unsigned int trace_ctx = 0;
+
+ trace_ctx = tracing_gen_ctx();
+ event = trace_buffer_lock_reserve(buffer, TRACE_OBJECT,
+ sizeof(*entry), trace_ctx);
+ if (!event)
+ return;
+ entry = ring_buffer_event_data(event);
+ entry->ip = ip;
+ entry->parent_ip = parent_ip;
+ entry->object = object;
+
+ trace_buffer_unlock_commit(tr, buffer, event, trace_ctx);
+}
+
+static void
+trace_object_events_call(unsigned long ip, unsigned long parent_ip,
+ struct ftrace_ops *op, struct ftrace_regs *fregs)
+{
+ struct pt_regs *pt_regs = ftrace_get_regs(fregs);
+ struct trace_array *tr = op->private;
+ struct trace_array_cpu *data;
+ unsigned long obj;
+ long disabled;
+ int cpu, n;
+
+ preempt_disable_notrace();
+
+ cpu = raw_smp_processor_id();
+ data = per_cpu_ptr(tr->array_buffer.data, cpu);
+ disabled = atomic_inc_return(&data->disabled);
+ if (likely(disabled == 1)) {
+ if (object_empty(tr))
+ goto out;
+ for (n = 0; n < max_args_num; n++) {
+ obj = regs_get_kernel_argument(pt_regs, n);
+ if (object_exist((void *)obj, tr))
+ submit_trace_object(ip, parent_ip, obj, tr);
+ /* The parameters of a function may match multiple objects */
+ }
+ }
+out:
+ atomic_dec(&data->disabled);
+ preempt_enable_notrace();
+}
+
+static void
+trace_object_trigger(struct event_trigger_data *data,
+ struct trace_buffer *buffer, void *rec,
+ struct ring_buffer_event *event)
+{
+ struct objtrace_trigger_data *obj_data = data->private_data;
+ struct trace_array *tr = obj_data->tr;
+ struct ftrace_event_field *field;
+ void *obj = NULL;
+
+ field = obj_data->field;
+ memcpy(&obj, rec + field->offset, sizeof(obj));
+ set_trace_object(obj, tr);
+}
+
+static void
+trace_object_trigger_free(struct event_trigger_data *data)
+{
+ struct objtrace_trigger_data *obj_data = data->private_data;
+
+ if (WARN_ON_ONCE(data->ref <= 0))
+ return;
+
+ data->ref--;
+ if (!data->ref) {
+ exit_trace_object(obj_data->tr);
+ kfree(data->private_data);
+ trigger_data_free(data);
+ }
+}
+
+static void
+trace_object_count_trigger(struct event_trigger_data *data,
+ struct trace_buffer *buffer, void *rec,
+ struct ring_buffer_event *event)
+{
+ if (!data->count)
+ return;
+
+ if (data->count != -1)
+ (data->count)--;
+
+ trace_object_trigger(data, buffer, rec, event);
+}
+
+static int
+event_trigger_print(const char *name, struct seq_file *m,
+ void *data, char *filter_str, void *objtrace_data)
+{
+ long count = (long)data;
+ struct objtrace_trigger_data *obj_data = objtrace_data;
+
+ seq_puts(m, name);
+
+ seq_printf(m, ":%s", obj_data->objtrace_cmd);
+ seq_printf(m, ":%s", obj_data->field->name);
+
+ if (count == -1)
+ seq_puts(m, ":unlimited");
+ else
+ seq_printf(m, ":count=%ld", count);
+
+ if (filter_str)
+ seq_printf(m, " if %s\n", filter_str);
+ else
+ seq_putc(m, '\n');
+
+ return 0;
+}
+
+static int event_object_trigger_init(struct event_trigger_data *data)
+{
+ struct objtrace_trigger_data *obj_data = data->private_data;
+ int ret;
+
+ if (!data->ref) {
+ ret = init_trace_object(obj_data->tr);
+ if (ret)
+ return ret;
+ }
+ data->ref++;
+ return 0;
+}
+
+static int
+trace_object_trigger_print(struct seq_file *m, struct event_trigger_data *data)
+{
+ return event_trigger_print("objtrace", m, (void *)data->count,
+ data->filter_str, data->private_data);
+}
+
+static struct event_trigger_ops objecttrace_trigger_ops = {
+ .trigger = trace_object_trigger,
+ .print = trace_object_trigger_print,
+ .init = event_object_trigger_init,
+ .free = trace_object_trigger_free,
+};
+
+static struct event_trigger_ops objecttrace_count_trigger_ops = {
+ .trigger = trace_object_count_trigger,
+ .print = trace_object_trigger_print,
+ .init = event_object_trigger_init,
+ .free = trace_object_trigger_free,
+};
+
+static struct event_trigger_ops *
+objecttrace_get_trigger_ops(char *cmd, char *param)
+{
+ return param ? &objecttrace_count_trigger_ops : &objecttrace_trigger_ops;
+}
+
+static bool field_exist(struct trace_event_file *file,
+ struct event_command *cmd_ops,
+ const char *field_name)
+{
+ struct event_trigger_data *data;
+ struct objtrace_trigger_data *obj_data;
+
+ lockdep_assert_held(&event_mutex);
+
+ list_for_each_entry(data, &file->triggers, list) {
+ if (data->cmd_ops->trigger_type == cmd_ops->trigger_type) {
+ obj_data = data->private_data;
+ if (!strcmp(obj_data->field->name, field_name))
+ return true;
+ }
+ }
+
+ return false;
+}
+
+static int
+event_object_trigger_parse(struct event_command *cmd_ops,
+ struct trace_event_file *file,
+ char *glob, char *cmd, char *param_and_filter)
+{
+ struct event_trigger_data *trigger_data;
+ struct objtrace_trigger_data *obj_data;
+ struct ftrace_event_field *field;
+ char *objtrace_cmd, *arg;
+ char *param, *filter;
+ int ret;
+ bool remove;
+
+ remove = event_trigger_check_remove(glob);
+
+ /*
+ * separate the param and the filter:
+ * objtrace:add:OBJ[:COUNT] [if filter]
+ */
+ ret = event_trigger_separate_filter(param_and_filter, ¶m, &filter, true);
+ if (ret)
+ return ret;
+
+ objtrace_cmd = strsep(¶m, ":");
+ if (!objtrace_cmd || strcmp(objtrace_cmd, OBJTRACE_CMD_ADD)) {
+ pr_err("error objtrace command\n");
+ return -EINVAL;
+ }
+
+ arg = strsep(¶m, ":");
+ if (!arg)
+ return -EINVAL;
+
+ field = trace_find_event_field(file->event_call, arg);
+ if (!field)
+ return -EINVAL;
+
+ if (field->size != sizeof(void *)) {
+ pr_err("the size of the %s should be:%zu\n", field->name, sizeof(void *));
+ return -EINVAL;
+ }
+
+ if (remove && !field_exist(file, cmd_ops, field->name))
+ return -ENOENT;
+
+ obj_data = kzalloc(sizeof(*obj_data), GFP_KERNEL);
+ if (!obj_data)
+ return -ENOMEM;
+
+ obj_data->field = field;
+ obj_data->tr = file->tr;
+ snprintf(obj_data->objtrace_cmd, OBJTRACE_CMD_LEN, objtrace_cmd);
+
+ trigger_data = event_trigger_alloc(cmd_ops, cmd, param, obj_data);
+ if (!trigger_data) {
+ kfree(obj_data);
+ return -ENOMEM;
+ }
+ if (remove) {
+ event_trigger_unregister(cmd_ops, file, glob+1, trigger_data);
+ kfree(obj_data);
+ kfree(trigger_data);
+ return 0;
+ }
+
+ ret = event_trigger_parse_num(param, trigger_data);
+ if (ret)
+ goto out_free;
+
+ ret = event_trigger_set_filter(cmd_ops, file, filter, trigger_data);
+ if (ret < 0)
+ goto out_free;
+
+ ret = event_trigger_register(cmd_ops, file, glob, trigger_data);
+ if (ret)
+ goto out_free;
+
+ return ret;
+
+ out_free:
+ event_trigger_reset_filter(cmd_ops, trigger_data);
+ kfree(obj_data);
+ kfree(trigger_data);
+ return ret;
+}
+
+static struct event_command trigger_object_cmd = {
+ .name = "objtrace",
+ .trigger_type = ETT_TRACE_OBJECT,
+ .flags = EVENT_CMD_FL_NEEDS_REC,
+ .parse = event_object_trigger_parse,
+ .reg = register_trigger,
+ .unreg = unregister_trigger,
+ .get_trigger_ops = objecttrace_get_trigger_ops,
+ .set_filter = set_trigger_filter,
+};
+
+__init int register_trigger_object_cmd(void)
+{
+ int ret;
+
+ ret = register_event_command(&trigger_object_cmd);
+ WARN_ON(ret < 0);
+
+ return ret;
+}
+
+int allocate_objtrace_data(struct trace_array *tr)
+{
+ struct objtrace_data *obj_data;
+ struct ftrace_ops *fops;
+
+ obj_data = kzalloc(sizeof(*obj_data), GFP_KERNEL);
+ if (!obj_data)
+ return -ENOMEM;
+
+ raw_spin_lock_init(&obj_data->obj_data_lock);
+ obj_data->tr = tr;
+ fops = &obj_data->fops;
+ fops->func = trace_object_events_call;
+ fops->flags = FTRACE_OPS_FL_SAVE_REGS;
+ fops->private = tr;
+ list_add(&obj_data->head, &obj_data_head);
+
+ tr->obj_data = obj_data;
+
+ return 0;
+}
+
+static int init_trace_object(struct trace_array *tr)
+{
+ int ret;
+
+ ret = register_ftrace_function(&tr->obj_data->fops);
+ WARN_ON(ret < 0);
+
+ return ret;
+}
+
+void free_objtrace_data(struct trace_array *tr)
+{
+ kfree(tr->obj_data);
+ tr->obj_data = NULL;
+}
+
+static void exit_trace_object(struct trace_array *tr)
+{
+ struct objtrace_data *obj_data = tr->obj_data;
+
+ obj_data->num_traced_obj = 0;
+ WARN_ONCE(unregister_ftrace_function(&obj_data->fops),
+ "can't unregister ftrace for trace object\n");
+}
diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c
index 67f47ea27921..34ff7b4dc521 100644
--- a/kernel/trace/trace_output.c
+++ b/kernel/trace/trace_output.c
@@ -1551,6 +1551,45 @@ static struct trace_event trace_func_repeats_event = {
.funcs = &trace_func_repeats_funcs,
};
+/* TRACE_OBJECT */
+static enum print_line_t trace_object_print(struct trace_iterator *iter, int flags,
+ struct trace_event *event)
+{
+ struct trace_object_entry *field;
+ struct trace_seq *s = &iter->seq;
+
+ trace_assign_type(field, iter->ent);
+ print_fn_trace(s, field->ip, field->parent_ip, flags);
+ trace_seq_printf(s, " object:0x%lx", field->object);
+ trace_seq_putc(s, '\n');
+
+ return trace_handle_return(s);
+}
+
+static enum print_line_t trace_object_raw(struct trace_iterator *iter, int flags,
+ struct trace_event *event)
+{
+ struct trace_object_entry *field;
+
+ trace_assign_type(field, iter->ent);
+
+ trace_seq_printf(&iter->seq, "%lx %lx\n",
+ field->ip,
+ field->parent_ip);
+
+ return trace_handle_return(&iter->seq);
+}
+
+static struct trace_event_functions trace_object_funcs = {
+ .trace = trace_object_print,
+ .raw = trace_object_raw,
+};
+
+static struct trace_event trace_object_event = {
+ .type = TRACE_OBJECT,
+ .funcs = &trace_object_funcs,
+};
+
static struct trace_event *events[] __initdata = {
&trace_fn_event,
&trace_ctx_event,
@@ -1565,6 +1604,7 @@ static struct trace_event *events[] __initdata = {
&trace_timerlat_event,
&trace_raw_data_event,
&trace_func_repeats_event,
+ &trace_object_event,
NULL
};
--
2.25.1
^ permalink raw reply related [flat|nested] 12+ messages in thread* [PATCH v13 2/4] trace/objtrace: Get the value of the object
2022-06-26 2:56 [PATCH v13 0/4] trace: Introduce objtrace trigger to trace the kernel object Jeff Xie
2022-06-26 2:56 ` [PATCH v13 1/4] trace: Add trace any " Jeff Xie
@ 2022-06-26 2:56 ` Jeff Xie
2022-06-26 15:13 ` Masami Hiramatsu
2022-06-26 2:56 ` [PATCH v13 3/4] selftests/ftrace: Add testcases for objtrace Jeff Xie
2022-06-26 2:56 ` [PATCH v13 4/4] Documentation: trace/objtrace: Add documentation " Jeff Xie
3 siblings, 1 reply; 12+ messages in thread
From: Jeff Xie @ 2022-06-26 2:56 UTC (permalink / raw)
To: rostedt
Cc: mingo, mhiramat, zanussi, linux-kernel, linux-kselftest, shuah,
linux-doc, corbet, chensong_2000, Jeff Xie
Using objtrace trigger to get the value of the object which from the kernel
function parameter.
Syntax:
objtrace:add:obj[,offset][:type][:count][if <filter>]
Usage:
# echo 'p bio_add_page arg1=$arg1' > ./kprobe_events
# gdb vmlinux
(gdb) p &(((struct bio *)0)->bi_iter.bi_size)
$1 = (unsigned int *) 0x28
# echo 'objtrace:add:arg1,0x28:u32:1 if comm == "cat"' > ./events/kprobes/ \
p_bio_add_page_0/trigger
# cat /test.txt
Signed-off-by: Jeff Xie <xiehuan09@gmail.com>
---
kernel/trace/trace.c | 2 +-
kernel/trace/trace_entries.h | 5 +-
kernel/trace/trace_object.c | 187 ++++++++++++++++++++++++++++++++---
kernel/trace/trace_output.c | 6 +-
4 files changed, 181 insertions(+), 19 deletions(-)
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 7074ad8bc1a0..37f5cbfa5347 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -5628,7 +5628,7 @@ static const char readme_msg[] =
"\t disable_hist:<system>:<event>\n"
#endif
#ifdef CONFIG_TRACE_OBJECT
- "\t objtrace:add:obj[:count][if <filter>]\n"
+ "\t objtrace:add:obj[,offset][:type][:count][if <filter>]\n"
#endif
#ifdef CONFIG_STACKTRACE
"\t\t stacktrace\n"
diff --git a/kernel/trace/trace_entries.h b/kernel/trace/trace_entries.h
index bb120d9498a9..2407c45a568c 100644
--- a/kernel/trace/trace_entries.h
+++ b/kernel/trace/trace_entries.h
@@ -413,8 +413,9 @@ FTRACE_ENTRY(object, trace_object_entry,
__field( unsigned long, ip )
__field( unsigned long, parent_ip )
__field( unsigned long, object )
+ __field( unsigned long, value )
),
- F_printk(" %ps <-- %ps object:%lx\n",
- (void *)__entry->ip, (void *)__entry->parent_ip, __entry->object)
+ F_printk(" %ps <-- %ps object:%lx value:%lx\n", (void *)__entry->ip,
+ (void *)__entry->parent_ip, __entry->object, __entry->value)
);
diff --git a/kernel/trace/trace_object.c b/kernel/trace/trace_object.c
index 19ec4b1c0186..611341abeb7c 100644
--- a/kernel/trace/trace_object.c
+++ b/kernel/trace/trace_object.c
@@ -16,8 +16,14 @@ static const int max_args_num = 6;
static void exit_trace_object(struct trace_array *tr);
static int init_trace_object(struct trace_array *tr);
+/*
+ * get the offset from the special object and
+ * the type size of the value
+ */
struct object_instance {
void *obj;
+ int obj_offset;
+ int obj_value_type_size;
struct trace_array *tr;
};
@@ -25,9 +31,23 @@ struct object_instance {
struct objtrace_trigger_data {
struct ftrace_event_field *field;
char objtrace_cmd[OBJTRACE_CMD_LEN];
+ int obj_offset;
+ int obj_value_type_size;
struct trace_array *tr;
};
+/* get the type size for the special object */
+struct objtrace_fetch_type {
+ char *name;
+ int type_size;
+};
+
+enum objattr {
+ OBJ_OFFSET,
+ OBJ_VAL_TYPE_SIZE,
+ MAX_OBJ_ATTR
+};
+
/* objtrace data with fops and objtrace_instances */
struct objtrace_data {
struct list_head head;
@@ -67,6 +87,35 @@ static bool object_exist(void *obj, struct trace_array *tr)
return false;
}
+static int get_object_attr(void *obj, int objattr,
+ struct trace_array *tr, int *result)
+{
+ int i, max;
+ struct objtrace_data *obj_data;
+
+ obj_data = get_obj_data(tr);
+ if (!obj_data)
+ return -EINVAL;
+
+ max = READ_ONCE(obj_data->num_traced_obj);
+ smp_rmb();
+ for (i = 0; i < max; i++) {
+ if (obj_data->traced_obj[i].obj == obj) {
+ switch (objattr) {
+ case OBJ_OFFSET:
+ *result = obj_data->traced_obj[i].obj_offset;
+ return 0;
+ case OBJ_VAL_TYPE_SIZE:
+ *result = obj_data->traced_obj[i].obj_value_type_size;
+ return 0;
+ default:
+ return -EINVAL;
+ }
+ }
+ }
+ return -EINVAL;
+}
+
static bool object_empty(struct trace_array *tr)
{
struct objtrace_data *obj_data;
@@ -78,7 +127,8 @@ static bool object_empty(struct trace_array *tr)
return !READ_ONCE(obj_data->num_traced_obj);
}
-static void set_trace_object(void *obj, struct trace_array *tr)
+static void set_trace_object(void *obj, int obj_offset,
+ int obj_value_type_size, struct trace_array *tr)
{
unsigned long flags;
struct object_instance *obj_ins;
@@ -103,6 +153,8 @@ static void set_trace_object(void *obj, struct trace_array *tr)
}
obj_ins = &obj_data->traced_obj[READ_ONCE(obj_data->num_traced_obj)];
obj_ins->obj = obj;
+ obj_ins->obj_value_type_size = obj_value_type_size;
+ obj_ins->obj_offset = obj_offset;
obj_ins->tr = tr;
/* make sure the num_traced_obj update always appears after traced_obj update */
smp_wmb();
@@ -112,7 +164,7 @@ static void set_trace_object(void *obj, struct trace_array *tr)
}
static void submit_trace_object(unsigned long ip, unsigned long parent_ip,
- unsigned long object, struct trace_array *tr)
+ unsigned long object, unsigned long value, struct trace_array *tr)
{
struct trace_buffer *buffer = tr->array_buffer.buffer;
@@ -129,10 +181,43 @@ static void submit_trace_object(unsigned long ip, unsigned long parent_ip,
entry->ip = ip;
entry->parent_ip = parent_ip;
entry->object = object;
+ entry->value = value;
trace_buffer_unlock_commit(tr, buffer, event, trace_ctx);
}
+static inline long get_object_value(unsigned long *val, void *obj, int type_size)
+{
+ char tmp[sizeof(u64)];
+ long ret = 0;
+
+ ret = copy_from_kernel_nofault(tmp, obj, sizeof(tmp));
+ if (ret)
+ return ret;
+ switch (type_size) {
+ case 1: {
+ *val = (unsigned long)*(u8 *)tmp;
+ break;
+ }
+ case 2: {
+ *val = (unsigned long)*(u16 *)tmp;
+ break;
+ }
+ case 4: {
+ *val = (unsigned long)*(u32 *)tmp;
+ break;
+ }
+ case 8: {
+ *val = (unsigned long)*(u64 *)tmp;
+ break;
+ }
+ default:
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
static void
trace_object_events_call(unsigned long ip, unsigned long parent_ip,
struct ftrace_ops *op, struct ftrace_regs *fregs)
@@ -140,7 +225,8 @@ trace_object_events_call(unsigned long ip, unsigned long parent_ip,
struct pt_regs *pt_regs = ftrace_get_regs(fregs);
struct trace_array *tr = op->private;
struct trace_array_cpu *data;
- unsigned long obj;
+ int ret, val_type_size, obj_offset;
+ unsigned long obj, val;
long disabled;
int cpu, n;
@@ -154,8 +240,21 @@ trace_object_events_call(unsigned long ip, unsigned long parent_ip,
goto out;
for (n = 0; n < max_args_num; n++) {
obj = regs_get_kernel_argument(pt_regs, n);
- if (object_exist((void *)obj, tr))
- submit_trace_object(ip, parent_ip, obj, tr);
+ if (object_exist((void *)obj, tr)) {
+ ret = get_object_attr((void *)obj, OBJ_OFFSET,
+ tr, &obj_offset);
+ if (unlikely(ret) < 0)
+ goto out;
+ ret = get_object_attr((void *)obj, OBJ_VAL_TYPE_SIZE,
+ tr, &val_type_size);
+ if (unlikely(ret) < 0)
+ goto out;
+ if (get_object_value(&val, (void *)(obj + obj_offset),
+ val_type_size))
+ continue;
+
+ submit_trace_object(ip, parent_ip, obj, val, tr);
+ }
/* The parameters of a function may match multiple objects */
}
}
@@ -176,9 +275,23 @@ trace_object_trigger(struct event_trigger_data *data,
field = obj_data->field;
memcpy(&obj, rec + field->offset, sizeof(obj));
- set_trace_object(obj, tr);
+ /* set the offset from the special object and the type size of the value*/
+ set_trace_object(obj, obj_data->obj_offset,
+ obj_data->obj_value_type_size, tr);
}
+static const struct objtrace_fetch_type objtrace_fetch_types[] = {
+ {"u8", 1},
+ {"x8", 1},
+ {"u16", 2},
+ {"x16", 2},
+ {"u32", 4},
+ {"x32", 4},
+ {"u64", 8},
+ {"x64", 8},
+ {NULL, 0},
+};
+
static void
trace_object_trigger_free(struct event_trigger_data *data)
{
@@ -213,14 +326,25 @@ static int
event_trigger_print(const char *name, struct seq_file *m,
void *data, char *filter_str, void *objtrace_data)
{
+ int i;
long count = (long)data;
struct objtrace_trigger_data *obj_data = objtrace_data;
+ const char *value_type_name;
seq_puts(m, name);
seq_printf(m, ":%s", obj_data->objtrace_cmd);
seq_printf(m, ":%s", obj_data->field->name);
+ if (obj_data->obj_offset)
+ seq_printf(m, ",0x%x", obj_data->obj_offset);
+ for (i = 0; objtrace_fetch_types[i].name; i++) {
+ if (objtrace_fetch_types[i].type_size == obj_data->obj_value_type_size) {
+ value_type_name = objtrace_fetch_types[i].name;
+ break;
+ }
+ }
+ seq_printf(m, ":%s", value_type_name);
if (count == -1)
seq_puts(m, ":unlimited");
else
@@ -303,16 +427,18 @@ event_object_trigger_parse(struct event_command *cmd_ops,
struct event_trigger_data *trigger_data;
struct objtrace_trigger_data *obj_data;
struct ftrace_event_field *field;
- char *objtrace_cmd, *arg;
- char *param, *filter;
- int ret;
+ char *objtrace_cmd, *obj;
+ char *param, *filter, *str, *type;
+ int ret, i, def_type_size, obj_value_type_size = 0;
+ char *tmp_saved_param;
+ long offset = 0;
bool remove;
remove = event_trigger_check_remove(glob);
/*
* separate the param and the filter:
- * objtrace:add:OBJ[:COUNT] [if filter]
+ * objtrace:add:OBJ[,OFFS][:TYPE][:COUNT] [if filter]
*/
ret = event_trigger_separate_filter(param_and_filter, ¶m, &filter, true);
if (ret)
@@ -324,11 +450,44 @@ event_object_trigger_parse(struct event_command *cmd_ops,
return -EINVAL;
}
- arg = strsep(¶m, ":");
- if (!arg)
+ obj = strsep(¶m, ":");
+ if (!obj)
return -EINVAL;
- field = trace_find_event_field(file->event_call, arg);
+ str = strchr(obj, ',');
+ if (!str)
+ offset = 0;
+ else {
+ *str++ = '\0';
+ ret = kstrtol(str, 0, &offset);
+ if (ret)
+ return -EINVAL;
+ }
+ def_type_size = sizeof(void *);
+ if (!param) {
+ obj_value_type_size = def_type_size;
+ goto skip_get_type;
+ }
+ tmp_saved_param = param;
+ type = strsep(¶m, ":");
+ if (!type)
+ obj_value_type_size = def_type_size;
+ /* if this is the trigger count */
+ else if (isdigit(type[0])) {
+ obj_value_type_size = def_type_size;
+ param = tmp_saved_param;
+ } else {
+ for (i = 0; objtrace_fetch_types[i].name; i++) {
+ if (strcmp(objtrace_fetch_types[i].name, type) == 0) {
+ obj_value_type_size = objtrace_fetch_types[i].type_size;
+ break;
+ }
+ }
+ }
+ if (!obj_value_type_size)
+ return -EINVAL;
+skip_get_type:
+ field = trace_find_event_field(file->event_call, obj);
if (!field)
return -EINVAL;
@@ -345,6 +504,8 @@ event_object_trigger_parse(struct event_command *cmd_ops,
return -ENOMEM;
obj_data->field = field;
+ obj_data->obj_offset = offset;
+ obj_data->obj_value_type_size = obj_value_type_size;
obj_data->tr = file->tr;
snprintf(obj_data->objtrace_cmd, OBJTRACE_CMD_LEN, objtrace_cmd);
diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c
index 34ff7b4dc521..a45871b52dcc 100644
--- a/kernel/trace/trace_output.c
+++ b/kernel/trace/trace_output.c
@@ -1561,6 +1561,7 @@ static enum print_line_t trace_object_print(struct trace_iterator *iter, int fla
trace_assign_type(field, iter->ent);
print_fn_trace(s, field->ip, field->parent_ip, flags);
trace_seq_printf(s, " object:0x%lx", field->object);
+ trace_seq_printf(s, " value:0x%lx", field->value);
trace_seq_putc(s, '\n');
return trace_handle_return(s);
@@ -1573,9 +1574,8 @@ static enum print_line_t trace_object_raw(struct trace_iterator *iter, int flags
trace_assign_type(field, iter->ent);
- trace_seq_printf(&iter->seq, "%lx %lx\n",
- field->ip,
- field->parent_ip);
+ trace_seq_printf(&iter->seq, "%lx %lx %lx %lx\n", field->ip,
+ field->parent_ip, field->object, field->value);
return trace_handle_return(&iter->seq);
}
--
2.25.1
^ permalink raw reply related [flat|nested] 12+ messages in thread* Re: [PATCH v13 2/4] trace/objtrace: Get the value of the object
2022-06-26 2:56 ` [PATCH v13 2/4] trace/objtrace: Get the value of the object Jeff Xie
@ 2022-06-26 15:13 ` Masami Hiramatsu
0 siblings, 0 replies; 12+ messages in thread
From: Masami Hiramatsu @ 2022-06-26 15:13 UTC (permalink / raw)
To: Jeff Xie
Cc: rostedt, mingo, mhiramat, zanussi, linux-kernel, linux-kselftest,
shuah, linux-doc, corbet, chensong_2000
On Sun, 26 Jun 2022 10:56:02 +0800
Jeff Xie <xiehuan09@gmail.com> wrote:
> Using objtrace trigger to get the value of the object which from the kernel
> function parameter.
>
> Syntax:
> objtrace:add:obj[,offset][:type][:count][if <filter>]
>
> Usage:
> # echo 'p bio_add_page arg1=$arg1' > ./kprobe_events
> # gdb vmlinux
> (gdb) p &(((struct bio *)0)->bi_iter.bi_size)
> $1 = (unsigned int *) 0x28
> # echo 'objtrace:add:arg1,0x28:u32:1 if comm == "cat"' > ./events/kprobes/ \
> p_bio_add_page_0/trigger
> # cat /test.txt
>
Thanks for update! This looks good to me.
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
> Signed-off-by: Jeff Xie <xiehuan09@gmail.com>
> ---
> kernel/trace/trace.c | 2 +-
> kernel/trace/trace_entries.h | 5 +-
> kernel/trace/trace_object.c | 187 ++++++++++++++++++++++++++++++++---
> kernel/trace/trace_output.c | 6 +-
> 4 files changed, 181 insertions(+), 19 deletions(-)
>
> diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
> index 7074ad8bc1a0..37f5cbfa5347 100644
> --- a/kernel/trace/trace.c
> +++ b/kernel/trace/trace.c
> @@ -5628,7 +5628,7 @@ static const char readme_msg[] =
> "\t disable_hist:<system>:<event>\n"
> #endif
> #ifdef CONFIG_TRACE_OBJECT
> - "\t objtrace:add:obj[:count][if <filter>]\n"
> + "\t objtrace:add:obj[,offset][:type][:count][if <filter>]\n"
> #endif
> #ifdef CONFIG_STACKTRACE
> "\t\t stacktrace\n"
> diff --git a/kernel/trace/trace_entries.h b/kernel/trace/trace_entries.h
> index bb120d9498a9..2407c45a568c 100644
> --- a/kernel/trace/trace_entries.h
> +++ b/kernel/trace/trace_entries.h
> @@ -413,8 +413,9 @@ FTRACE_ENTRY(object, trace_object_entry,
> __field( unsigned long, ip )
> __field( unsigned long, parent_ip )
> __field( unsigned long, object )
> + __field( unsigned long, value )
> ),
>
> - F_printk(" %ps <-- %ps object:%lx\n",
> - (void *)__entry->ip, (void *)__entry->parent_ip, __entry->object)
> + F_printk(" %ps <-- %ps object:%lx value:%lx\n", (void *)__entry->ip,
> + (void *)__entry->parent_ip, __entry->object, __entry->value)
> );
> diff --git a/kernel/trace/trace_object.c b/kernel/trace/trace_object.c
> index 19ec4b1c0186..611341abeb7c 100644
> --- a/kernel/trace/trace_object.c
> +++ b/kernel/trace/trace_object.c
> @@ -16,8 +16,14 @@ static const int max_args_num = 6;
> static void exit_trace_object(struct trace_array *tr);
> static int init_trace_object(struct trace_array *tr);
>
> +/*
> + * get the offset from the special object and
> + * the type size of the value
> + */
> struct object_instance {
> void *obj;
> + int obj_offset;
> + int obj_value_type_size;
> struct trace_array *tr;
> };
>
> @@ -25,9 +31,23 @@ struct object_instance {
> struct objtrace_trigger_data {
> struct ftrace_event_field *field;
> char objtrace_cmd[OBJTRACE_CMD_LEN];
> + int obj_offset;
> + int obj_value_type_size;
> struct trace_array *tr;
> };
>
> +/* get the type size for the special object */
> +struct objtrace_fetch_type {
> + char *name;
> + int type_size;
> +};
> +
> +enum objattr {
> + OBJ_OFFSET,
> + OBJ_VAL_TYPE_SIZE,
> + MAX_OBJ_ATTR
> +};
> +
> /* objtrace data with fops and objtrace_instances */
> struct objtrace_data {
> struct list_head head;
> @@ -67,6 +87,35 @@ static bool object_exist(void *obj, struct trace_array *tr)
> return false;
> }
>
> +static int get_object_attr(void *obj, int objattr,
> + struct trace_array *tr, int *result)
> +{
> + int i, max;
> + struct objtrace_data *obj_data;
> +
> + obj_data = get_obj_data(tr);
> + if (!obj_data)
> + return -EINVAL;
> +
> + max = READ_ONCE(obj_data->num_traced_obj);
> + smp_rmb();
> + for (i = 0; i < max; i++) {
> + if (obj_data->traced_obj[i].obj == obj) {
> + switch (objattr) {
> + case OBJ_OFFSET:
> + *result = obj_data->traced_obj[i].obj_offset;
> + return 0;
> + case OBJ_VAL_TYPE_SIZE:
> + *result = obj_data->traced_obj[i].obj_value_type_size;
> + return 0;
> + default:
> + return -EINVAL;
> + }
> + }
> + }
> + return -EINVAL;
> +}
> +
> static bool object_empty(struct trace_array *tr)
> {
> struct objtrace_data *obj_data;
> @@ -78,7 +127,8 @@ static bool object_empty(struct trace_array *tr)
> return !READ_ONCE(obj_data->num_traced_obj);
> }
>
> -static void set_trace_object(void *obj, struct trace_array *tr)
> +static void set_trace_object(void *obj, int obj_offset,
> + int obj_value_type_size, struct trace_array *tr)
> {
> unsigned long flags;
> struct object_instance *obj_ins;
> @@ -103,6 +153,8 @@ static void set_trace_object(void *obj, struct trace_array *tr)
> }
> obj_ins = &obj_data->traced_obj[READ_ONCE(obj_data->num_traced_obj)];
> obj_ins->obj = obj;
> + obj_ins->obj_value_type_size = obj_value_type_size;
> + obj_ins->obj_offset = obj_offset;
> obj_ins->tr = tr;
> /* make sure the num_traced_obj update always appears after traced_obj update */
> smp_wmb();
> @@ -112,7 +164,7 @@ static void set_trace_object(void *obj, struct trace_array *tr)
> }
>
> static void submit_trace_object(unsigned long ip, unsigned long parent_ip,
> - unsigned long object, struct trace_array *tr)
> + unsigned long object, unsigned long value, struct trace_array *tr)
> {
>
> struct trace_buffer *buffer = tr->array_buffer.buffer;
> @@ -129,10 +181,43 @@ static void submit_trace_object(unsigned long ip, unsigned long parent_ip,
> entry->ip = ip;
> entry->parent_ip = parent_ip;
> entry->object = object;
> + entry->value = value;
>
> trace_buffer_unlock_commit(tr, buffer, event, trace_ctx);
> }
>
> +static inline long get_object_value(unsigned long *val, void *obj, int type_size)
> +{
> + char tmp[sizeof(u64)];
> + long ret = 0;
> +
> + ret = copy_from_kernel_nofault(tmp, obj, sizeof(tmp));
> + if (ret)
> + return ret;
> + switch (type_size) {
> + case 1: {
> + *val = (unsigned long)*(u8 *)tmp;
> + break;
> + }
> + case 2: {
> + *val = (unsigned long)*(u16 *)tmp;
> + break;
> + }
> + case 4: {
> + *val = (unsigned long)*(u32 *)tmp;
> + break;
> + }
> + case 8: {
> + *val = (unsigned long)*(u64 *)tmp;
> + break;
> + }
> + default:
> + return -EINVAL;
> + }
> +
> + return 0;
> +}
> +
> static void
> trace_object_events_call(unsigned long ip, unsigned long parent_ip,
> struct ftrace_ops *op, struct ftrace_regs *fregs)
> @@ -140,7 +225,8 @@ trace_object_events_call(unsigned long ip, unsigned long parent_ip,
> struct pt_regs *pt_regs = ftrace_get_regs(fregs);
> struct trace_array *tr = op->private;
> struct trace_array_cpu *data;
> - unsigned long obj;
> + int ret, val_type_size, obj_offset;
> + unsigned long obj, val;
> long disabled;
> int cpu, n;
>
> @@ -154,8 +240,21 @@ trace_object_events_call(unsigned long ip, unsigned long parent_ip,
> goto out;
> for (n = 0; n < max_args_num; n++) {
> obj = regs_get_kernel_argument(pt_regs, n);
> - if (object_exist((void *)obj, tr))
> - submit_trace_object(ip, parent_ip, obj, tr);
> + if (object_exist((void *)obj, tr)) {
> + ret = get_object_attr((void *)obj, OBJ_OFFSET,
> + tr, &obj_offset);
> + if (unlikely(ret) < 0)
> + goto out;
> + ret = get_object_attr((void *)obj, OBJ_VAL_TYPE_SIZE,
> + tr, &val_type_size);
> + if (unlikely(ret) < 0)
> + goto out;
> + if (get_object_value(&val, (void *)(obj + obj_offset),
> + val_type_size))
> + continue;
> +
> + submit_trace_object(ip, parent_ip, obj, val, tr);
> + }
> /* The parameters of a function may match multiple objects */
> }
> }
> @@ -176,9 +275,23 @@ trace_object_trigger(struct event_trigger_data *data,
>
> field = obj_data->field;
> memcpy(&obj, rec + field->offset, sizeof(obj));
> - set_trace_object(obj, tr);
> + /* set the offset from the special object and the type size of the value*/
> + set_trace_object(obj, obj_data->obj_offset,
> + obj_data->obj_value_type_size, tr);
> }
>
> +static const struct objtrace_fetch_type objtrace_fetch_types[] = {
> + {"u8", 1},
> + {"x8", 1},
> + {"u16", 2},
> + {"x16", 2},
> + {"u32", 4},
> + {"x32", 4},
> + {"u64", 8},
> + {"x64", 8},
> + {NULL, 0},
> +};
> +
> static void
> trace_object_trigger_free(struct event_trigger_data *data)
> {
> @@ -213,14 +326,25 @@ static int
> event_trigger_print(const char *name, struct seq_file *m,
> void *data, char *filter_str, void *objtrace_data)
> {
> + int i;
> long count = (long)data;
> struct objtrace_trigger_data *obj_data = objtrace_data;
> + const char *value_type_name;
>
> seq_puts(m, name);
>
> seq_printf(m, ":%s", obj_data->objtrace_cmd);
> seq_printf(m, ":%s", obj_data->field->name);
> + if (obj_data->obj_offset)
> + seq_printf(m, ",0x%x", obj_data->obj_offset);
>
> + for (i = 0; objtrace_fetch_types[i].name; i++) {
> + if (objtrace_fetch_types[i].type_size == obj_data->obj_value_type_size) {
> + value_type_name = objtrace_fetch_types[i].name;
> + break;
> + }
> + }
> + seq_printf(m, ":%s", value_type_name);
> if (count == -1)
> seq_puts(m, ":unlimited");
> else
> @@ -303,16 +427,18 @@ event_object_trigger_parse(struct event_command *cmd_ops,
> struct event_trigger_data *trigger_data;
> struct objtrace_trigger_data *obj_data;
> struct ftrace_event_field *field;
> - char *objtrace_cmd, *arg;
> - char *param, *filter;
> - int ret;
> + char *objtrace_cmd, *obj;
> + char *param, *filter, *str, *type;
> + int ret, i, def_type_size, obj_value_type_size = 0;
> + char *tmp_saved_param;
> + long offset = 0;
> bool remove;
>
> remove = event_trigger_check_remove(glob);
>
> /*
> * separate the param and the filter:
> - * objtrace:add:OBJ[:COUNT] [if filter]
> + * objtrace:add:OBJ[,OFFS][:TYPE][:COUNT] [if filter]
> */
> ret = event_trigger_separate_filter(param_and_filter, ¶m, &filter, true);
> if (ret)
> @@ -324,11 +450,44 @@ event_object_trigger_parse(struct event_command *cmd_ops,
> return -EINVAL;
> }
>
> - arg = strsep(¶m, ":");
> - if (!arg)
> + obj = strsep(¶m, ":");
> + if (!obj)
> return -EINVAL;
>
> - field = trace_find_event_field(file->event_call, arg);
> + str = strchr(obj, ',');
> + if (!str)
> + offset = 0;
> + else {
> + *str++ = '\0';
> + ret = kstrtol(str, 0, &offset);
> + if (ret)
> + return -EINVAL;
> + }
> + def_type_size = sizeof(void *);
> + if (!param) {
> + obj_value_type_size = def_type_size;
> + goto skip_get_type;
> + }
> + tmp_saved_param = param;
> + type = strsep(¶m, ":");
> + if (!type)
> + obj_value_type_size = def_type_size;
> + /* if this is the trigger count */
> + else if (isdigit(type[0])) {
> + obj_value_type_size = def_type_size;
> + param = tmp_saved_param;
> + } else {
> + for (i = 0; objtrace_fetch_types[i].name; i++) {
> + if (strcmp(objtrace_fetch_types[i].name, type) == 0) {
> + obj_value_type_size = objtrace_fetch_types[i].type_size;
> + break;
> + }
> + }
> + }
> + if (!obj_value_type_size)
> + return -EINVAL;
> +skip_get_type:
> + field = trace_find_event_field(file->event_call, obj);
> if (!field)
> return -EINVAL;
>
> @@ -345,6 +504,8 @@ event_object_trigger_parse(struct event_command *cmd_ops,
> return -ENOMEM;
>
> obj_data->field = field;
> + obj_data->obj_offset = offset;
> + obj_data->obj_value_type_size = obj_value_type_size;
> obj_data->tr = file->tr;
> snprintf(obj_data->objtrace_cmd, OBJTRACE_CMD_LEN, objtrace_cmd);
>
> diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c
> index 34ff7b4dc521..a45871b52dcc 100644
> --- a/kernel/trace/trace_output.c
> +++ b/kernel/trace/trace_output.c
> @@ -1561,6 +1561,7 @@ static enum print_line_t trace_object_print(struct trace_iterator *iter, int fla
> trace_assign_type(field, iter->ent);
> print_fn_trace(s, field->ip, field->parent_ip, flags);
> trace_seq_printf(s, " object:0x%lx", field->object);
> + trace_seq_printf(s, " value:0x%lx", field->value);
> trace_seq_putc(s, '\n');
>
> return trace_handle_return(s);
> @@ -1573,9 +1574,8 @@ static enum print_line_t trace_object_raw(struct trace_iterator *iter, int flags
>
> trace_assign_type(field, iter->ent);
>
> - trace_seq_printf(&iter->seq, "%lx %lx\n",
> - field->ip,
> - field->parent_ip);
> + trace_seq_printf(&iter->seq, "%lx %lx %lx %lx\n", field->ip,
> + field->parent_ip, field->object, field->value);
>
> return trace_handle_return(&iter->seq);
> }
> --
> 2.25.1
>
--
Masami Hiramatsu (Google) <mhiramat@kernel.org>
^ permalink raw reply [flat|nested] 12+ messages in thread
* [PATCH v13 3/4] selftests/ftrace: Add testcases for objtrace
2022-06-26 2:56 [PATCH v13 0/4] trace: Introduce objtrace trigger to trace the kernel object Jeff Xie
2022-06-26 2:56 ` [PATCH v13 1/4] trace: Add trace any " Jeff Xie
2022-06-26 2:56 ` [PATCH v13 2/4] trace/objtrace: Get the value of the object Jeff Xie
@ 2022-06-26 2:56 ` Jeff Xie
2022-07-08 16:26 ` Shuah Khan
2022-06-26 2:56 ` [PATCH v13 4/4] Documentation: trace/objtrace: Add documentation " Jeff Xie
3 siblings, 1 reply; 12+ messages in thread
From: Jeff Xie @ 2022-06-26 2:56 UTC (permalink / raw)
To: rostedt
Cc: mingo, mhiramat, zanussi, linux-kernel, linux-kselftest, shuah,
linux-doc, corbet, chensong_2000, Jeff Xie
Add a series of testcases to illustrate correct and incorrect usage of
objtrace trigger.
Signed-off-by: Jeff Xie <xiehuan09@gmail.com>
Tested-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
---
.../ftrace/test.d/trigger/trigger-objtrace.tc | 41 +++++++++++++++++++
1 file changed, 41 insertions(+)
create mode 100644 tools/testing/selftests/ftrace/test.d/trigger/trigger-objtrace.tc
diff --git a/tools/testing/selftests/ftrace/test.d/trigger/trigger-objtrace.tc b/tools/testing/selftests/ftrace/test.d/trigger/trigger-objtrace.tc
new file mode 100644
index 000000000000..d894442b6a30
--- /dev/null
+++ b/tools/testing/selftests/ftrace/test.d/trigger/trigger-objtrace.tc
@@ -0,0 +1,41 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+# description: event trigger - test objtrace-trigger
+# requires: kprobe_events "objtrace":README
+
+fail() { #msg
+ echo $1
+ exit_fail
+}
+
+echo 'p bio_add_page arg1=$arg1 arg2=$arg2' > kprobe_events
+
+FEATURE=`grep objtrace events/kprobes/p_bio_add_page_0/trigger`
+if [ -z "$FEATURE" ]; then
+ echo "objtrace trigger is not supported"
+ exit_unsupported
+fi
+
+echo "Test objtrace trigger"
+echo 'objtrace:add:arg1,0x28:u32:1 if comm == "cat"' > \
+ events/kprobes/p_bio_add_page_0/trigger
+if [ -z $? ]; then
+ fail "objtrace trigger syntax error"
+fi
+
+echo "Test objtrace semantic errors"
+
+# Being lack of objtrace command
+! echo 'objtrace:arg1,0x28:u32:1' > events/kprobes/p_bio_add_page_0/trigger
+# Bad parameter name
+! echo 'objtrace:add:argx:u32:1' > events/kprobes/p_bio_add_page_0/trigger
+# The parameter existed on event
+! echo 'objtrace:add:arg2:u32:1' > events/kprobes/p_bio_add_page_0/trigger
+
+echo "reset objtrace trigger"
+
+echo '!objtrace:add:arg1,0x28:u32' > \
+ events/kprobes/p_bio_add_page_0/trigger
+echo '-:p_bio_add_page_0' >> ./kprobe_events
+
+exit 0
--
2.25.1
^ permalink raw reply related [flat|nested] 12+ messages in thread* Re: [PATCH v13 3/4] selftests/ftrace: Add testcases for objtrace
2022-06-26 2:56 ` [PATCH v13 3/4] selftests/ftrace: Add testcases for objtrace Jeff Xie
@ 2022-07-08 16:26 ` Shuah Khan
0 siblings, 0 replies; 12+ messages in thread
From: Shuah Khan @ 2022-07-08 16:26 UTC (permalink / raw)
To: Jeff Xie, rostedt
Cc: mingo, mhiramat, zanussi, linux-kernel, linux-kselftest, shuah,
linux-doc, corbet, chensong_2000, Shuah Khan
On 6/25/22 8:56 PM, Jeff Xie wrote:
> Add a series of testcases to illustrate correct and incorrect usage of
> objtrace trigger.
>
> Signed-off-by: Jeff Xie <xiehuan09@gmail.com>
> Tested-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
> Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
> ---
> .../ftrace/test.d/trigger/trigger-objtrace.tc | 41 +++++++++++++++++++
> 1 file changed, 41 insertions(+)
> create mode 100644 tools/testing/selftests/ftrace/test.d/trigger/trigger-objtrace.tc
>
Assuming this patch depends on the other kernel/trace changes in this
series, here is my Ack for this series to go through tracing tree
Acked-by: Shuah Khan <skhan@linuxfoundation.org>
thanks,
-- Shuah
^ permalink raw reply [flat|nested] 12+ messages in thread
* [PATCH v13 4/4] Documentation: trace/objtrace: Add documentation for objtrace
2022-06-26 2:56 [PATCH v13 0/4] trace: Introduce objtrace trigger to trace the kernel object Jeff Xie
` (2 preceding siblings ...)
2022-06-26 2:56 ` [PATCH v13 3/4] selftests/ftrace: Add testcases for objtrace Jeff Xie
@ 2022-06-26 2:56 ` Jeff Xie
2022-06-27 2:14 ` Bagas Sanjaya
3 siblings, 1 reply; 12+ messages in thread
From: Jeff Xie @ 2022-06-26 2:56 UTC (permalink / raw)
To: rostedt
Cc: mingo, mhiramat, zanussi, linux-kernel, linux-kselftest, shuah,
linux-doc, corbet, chensong_2000, Jeff Xie
Added documentation explaining how to use objtrace trigger to get the value
of the object.
Signed-off-by: Jeff Xie <xiehuan09@gmail.com>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
---
Documentation/trace/events.rst | 83 ++++++++++++++++++++++++++++++++++
1 file changed, 83 insertions(+)
diff --git a/Documentation/trace/events.rst b/Documentation/trace/events.rst
index c47f381d0c00..0dc475160133 100644
--- a/Documentation/trace/events.rst
+++ b/Documentation/trace/events.rst
@@ -546,6 +546,89 @@ The following commands are supported:
See Documentation/trace/histogram.rst for details and examples.
+- objtrace
+
+ This command provides a way to get the value of any object, The object
+ can be obtained from the dynamic event(kprobe_event/uprobe_event) or the
+ static event(tracepoint).
+
+ Usage:
+ When using the kprobe event, only need to set the objtrace(a new trigger),
+ we can get the value of the object. The object is from the setting of the
+ kprobe event.
+
+ For example:
+ For the function bio_add_page():
+
+ int bio_add_page(struct bio *bio, struct page *page,
+ unsigned int len, unsigned int offset)
+
+ Firstly, we can set the base of the object, thus the first string "arg1"
+ stands for the value of the first parameter of this function bio_add_gage(),
+
+ # echo 'p bio_add_page arg1=$arg1' > ./kprobe_events
+
+ Secondly, we can get the value dynamically based on above object.
+
+ find the offset of the bi_size in struct bio:
+ $ gdb vmlinux
+ (gdb) p &(((struct bio *)0)->bi_iter.bi_size)
+ $1 = (unsigned int *) 0x28
+
+ # echo 'objtrace:add:arg1,0x28:u32:1 if comm == "cat"' > ./events/kprobes/ \
+ p_bio_add_page_0/trigger
+
+ # cd /sys/kernel/debug/tracing/
+ # echo 'p bio_add_page arg1=$arg1' > ./kprobe_events
+ # echo 'objtrace:add:arg1,0x28:u32:1 if comm == "cat"' > ./events/kprobes/p_bio_add_page_0/trigger
+
+ # du -sh /test.txt
+ 12.0K /test.txt
+
+ # cat /test.txt > /dev/null
+ # cat ./trace
+ # tracer: nop
+ #
+ # entries-in-buffer/entries-written: 128/128 #P:4
+ #
+ # _-----=> irqs-off/BH-disabled
+ # / _----=> need-resched
+ # | / _---=> hardirq/softirq
+ # || / _--=> preempt-depth
+ # ||| / _-=> migrate-disable
+ # |||| / delay
+ # TASK-PID CPU# ||||| TIMESTAMP FUNCTION
+ # | | | ||||| | |
+ cat-117 [002] ...1. 1.602243: __bio_try_merge_page <-bio_add_page object:0xffff88811bee4000 value:0x0
+ cat-117 [002] ...1. 1.602244: __bio_add_page <-bio_add_page object:0xffff88811bee4000 value:0x0
+ cat-117 [002] ...2. 1.602244: bio_add_page <-ext4_mpage_readpages object:0xffff88811bee4000 value:0x1000
+ cat-117 [002] ...1. 1.602245: __bio_try_merge_page <-bio_add_page object:0xffff88811bee4000 value:0x1000
+ cat-117 [002] ...1. 1.602245: __bio_add_page <-bio_add_page object:0xffff88811bee4000 value:0x1000
+ cat-117 [002] ...2. 1.602245: bio_add_page <-ext4_mpage_readpages object:0xffff88811bee4000 value:0x2000
+ cat-117 [002] ...1. 1.602245: __bio_try_merge_page <-bio_add_page object:0xffff88811bee4000 value:0x2000
+ cat-117 [002] ...1. 1.602245: __bio_add_page <-bio_add_page object:0xffff88811bee4000 value:0x2000
+ cat-117 [002] ...1. 1.602245: submit_bio <-ext4_mpage_readpages object:0xffff88811bee4000 value:0x3000
+ cat-117 [002] ...1. 1.602245: submit_bio_noacct <-ext4_mpage_readpages object:0xffff88811bee4000 value:0x3000
+ cat-117 [002] ...1. 1.602246: __submit_bio <-submit_bio_noacct object:0xffff88811bee4000 value:0x3000
+ cat-117 [002] ...1. 1.602246: submit_bio_checks <-__submit_bio object:0xffff88811bee4000 value:0x3000
+ cat-117 [002] ...1. 1.602246: __cond_resched <-submit_bio_checks object:0xffff88811bee4000 value:0x3000
+ cat-117 [002] ...1. 1.602246: should_fail_bio <-submit_bio_checks object:0xffff88811bee4000 value:0x3000
+ cat-117 [002] ...1. 1.602246: blk_mq_submit_bio <-submit_bio_noacct object:0xffff88811bee4000 value:0x3000
+ cat-117 [002] ...1. 1.602246: blk_attempt_plug_merge <-blk_mq_submit_bio object:0xffff88811bee4000 value:0x3000
+ cat-117 [002] ...1. 1.602246: blk_mq_sched_bio_merge <-blk_mq_submit_bio object:0xffff88811bee4000 value:0x3000
+ cat-117 [002] ...1. 1.602247: __rcu_read_lock <-blk_mq_submit_bio object:0xffff88811bee4000 value:0x3000
+ cat-117 [002] ...1. 1.602247: __rcu_read_unlock <-blk_mq_submit_bio object:0xffff88811bee4000 value:0x3000
+ cat-117 [002] ...1. 1.602247: __blk_mq_alloc_requests <-blk_mq_submit_bio object:0xffff88811bee4000 value:0x3000
+ <idle>-0 [002] d..3. 1.602298: bio_endio <-blk_update_request object:0xffff88811bee4000 value:0x0
+ <idle>-0 [002] d..3. 1.602298: mpage_end_io <-blk_update_request object:0xffff88811bee4000 value:0x0
+ <idle>-0 [002] d..3. 1.602298: __read_end_io <-blk_update_request object:0xffff88811bee4000 value:0x0
+ <idle>-0 [002] d..3. 1.602300: bio_put <-blk_update_request object:0xffff88811bee4000 value:0x0
+ <idle>-0 [002] d..3. 1.602300: bio_free <-blk_update_request object:0xffff88811bee4000 value:0x0
+ <idle>-0 [002] d..3. 1.602300: mempool_free <-blk_update_request object:0xffff88811bee4000 value:0x0
+ <idle>-0 [002] d..3. 1.602300: mempool_free_slab <-blk_update_request object:0xffff88811bee4000 value:0x0
+ <idle>-0 [002] d..3. 1.602300: kmem_cache_free <-blk_update_request object:0xffff88811bee4000 value:0x0
+ ...
+
7. In-kernel trace event API
============================
--
2.25.1
^ permalink raw reply related [flat|nested] 12+ messages in thread* Re: [PATCH v13 4/4] Documentation: trace/objtrace: Add documentation for objtrace
2022-06-26 2:56 ` [PATCH v13 4/4] Documentation: trace/objtrace: Add documentation " Jeff Xie
@ 2022-06-27 2:14 ` Bagas Sanjaya
2022-06-27 7:45 ` Jeff Xie
0 siblings, 1 reply; 12+ messages in thread
From: Bagas Sanjaya @ 2022-06-27 2:14 UTC (permalink / raw)
To: Jeff Xie
Cc: rostedt, mingo, mhiramat, zanussi, linux-kernel, linux-kselftest,
shuah, linux-doc, corbet, chensong_2000
On Sun, Jun 26, 2022 at 10:56:04AM +0800, Jeff Xie wrote:
> Added documentation explaining how to use objtrace trigger to get the value
> of the object.
>
Write "Add documentation..." instead.
> +- objtrace
> +
> + This command provides a way to get the value of any object, The object
> + can be obtained from the dynamic event(kprobe_event/uprobe_event) or the
> + static event(tracepoint).
> +
> + Usage:
> + When using the kprobe event, only need to set the objtrace(a new trigger),
> + we can get the value of the object. The object is from the setting of the
> + kprobe event.
> +
Did you mean "the object value can be obtained by only needing to set the
objtrace?"
> + For example:
> + For the function bio_add_page():
> +
> + int bio_add_page(struct bio *bio, struct page *page,
> + unsigned int len, unsigned int offset)
> +
> + Firstly, we can set the base of the object, thus the first string "arg1"
> + stands for the value of the first parameter of this function bio_add_gage(),
> +
> + # echo 'p bio_add_page arg1=$arg1' > ./kprobe_events
> +
Did you mean "the first parameter (arg1) is the parameter value of function
that is passed to kprobe_event, in this case the object base"?
> + Secondly, we can get the value dynamically based on above object.
> +
> + find the offset of the bi_size in struct bio:
> + $ gdb vmlinux
> + (gdb) p &(((struct bio *)0)->bi_iter.bi_size)
> + $1 = (unsigned int *) 0x28
> +
> + # echo 'objtrace:add:arg1,0x28:u32:1 if comm == "cat"' > ./events/kprobes/ \
> + p_bio_add_page_0/trigger
> +
> + # cd /sys/kernel/debug/tracing/
> + # echo 'p bio_add_page arg1=$arg1' > ./kprobe_events
> + # echo 'objtrace:add:arg1,0x28:u32:1 if comm == "cat"' > ./events/kprobes/p_bio_add_page_0/trigger
> +
> + # du -sh /test.txt
> + 12.0K /test.txt
> +
> + # cat /test.txt > /dev/null
> + # cat ./trace
> + # tracer: nop
> + #
> + # entries-in-buffer/entries-written: 128/128 #P:4
> + #
> + # _-----=> irqs-off/BH-disabled
> + # / _----=> need-resched
> + # | / _---=> hardirq/softirq
> + # || / _--=> preempt-depth
> + # ||| / _-=> migrate-disable
> + # |||| / delay
> + # TASK-PID CPU# ||||| TIMESTAMP FUNCTION
> + # | | | ||||| | |
> + cat-117 [002] ...1. 1.602243: __bio_try_merge_page <-bio_add_page object:0xffff88811bee4000 value:0x0
> + cat-117 [002] ...1. 1.602244: __bio_add_page <-bio_add_page object:0xffff88811bee4000 value:0x0
> + cat-117 [002] ...2. 1.602244: bio_add_page <-ext4_mpage_readpages object:0xffff88811bee4000 value:0x1000
> + cat-117 [002] ...1. 1.602245: __bio_try_merge_page <-bio_add_page object:0xffff88811bee4000 value:0x1000
> + cat-117 [002] ...1. 1.602245: __bio_add_page <-bio_add_page object:0xffff88811bee4000 value:0x1000
> + cat-117 [002] ...2. 1.602245: bio_add_page <-ext4_mpage_readpages object:0xffff88811bee4000 value:0x2000
> + cat-117 [002] ...1. 1.602245: __bio_try_merge_page <-bio_add_page object:0xffff88811bee4000 value:0x2000
> + cat-117 [002] ...1. 1.602245: __bio_add_page <-bio_add_page object:0xffff88811bee4000 value:0x2000
> + cat-117 [002] ...1. 1.602245: submit_bio <-ext4_mpage_readpages object:0xffff88811bee4000 value:0x3000
> + cat-117 [002] ...1. 1.602245: submit_bio_noacct <-ext4_mpage_readpages object:0xffff88811bee4000 value:0x3000
> + cat-117 [002] ...1. 1.602246: __submit_bio <-submit_bio_noacct object:0xffff88811bee4000 value:0x3000
> + cat-117 [002] ...1. 1.602246: submit_bio_checks <-__submit_bio object:0xffff88811bee4000 value:0x3000
> + cat-117 [002] ...1. 1.602246: __cond_resched <-submit_bio_checks object:0xffff88811bee4000 value:0x3000
> + cat-117 [002] ...1. 1.602246: should_fail_bio <-submit_bio_checks object:0xffff88811bee4000 value:0x3000
> + cat-117 [002] ...1. 1.602246: blk_mq_submit_bio <-submit_bio_noacct object:0xffff88811bee4000 value:0x3000
> + cat-117 [002] ...1. 1.602246: blk_attempt_plug_merge <-blk_mq_submit_bio object:0xffff88811bee4000 value:0x3000
> + cat-117 [002] ...1. 1.602246: blk_mq_sched_bio_merge <-blk_mq_submit_bio object:0xffff88811bee4000 value:0x3000
> + cat-117 [002] ...1. 1.602247: __rcu_read_lock <-blk_mq_submit_bio object:0xffff88811bee4000 value:0x3000
> + cat-117 [002] ...1. 1.602247: __rcu_read_unlock <-blk_mq_submit_bio object:0xffff88811bee4000 value:0x3000
> + cat-117 [002] ...1. 1.602247: __blk_mq_alloc_requests <-blk_mq_submit_bio object:0xffff88811bee4000 value:0x3000
> + <idle>-0 [002] d..3. 1.602298: bio_endio <-blk_update_request object:0xffff88811bee4000 value:0x0
> + <idle>-0 [002] d..3. 1.602298: mpage_end_io <-blk_update_request object:0xffff88811bee4000 value:0x0
> + <idle>-0 [002] d..3. 1.602298: __read_end_io <-blk_update_request object:0xffff88811bee4000 value:0x0
> + <idle>-0 [002] d..3. 1.602300: bio_put <-blk_update_request object:0xffff88811bee4000 value:0x0
> + <idle>-0 [002] d..3. 1.602300: bio_free <-blk_update_request object:0xffff88811bee4000 value:0x0
> + <idle>-0 [002] d..3. 1.602300: mempool_free <-blk_update_request object:0xffff88811bee4000 value:0x0
> + <idle>-0 [002] d..3. 1.602300: mempool_free_slab <-blk_update_request object:0xffff88811bee4000 value:0x0
> + <idle>-0 [002] d..3. 1.602300: kmem_cache_free <-blk_update_request object:0xffff88811bee4000 value:0x0
> + ...
> +
The output is messy, because for code example and output, literal code
blocks aren't used, hence trigger new warnings:
Documentation/trace/events.rst:564: WARNING: Inline emphasis start-string without end-string.
Documentation/trace/events.rst:564: WARNING: Inline emphasis start-string without end-string.
Documentation/trace/events.rst:573: WARNING: Inline emphasis start-string without end-string.
Documentation/trace/events.rst:573: WARNING: Inline emphasis start-string without end-string.
Documentation/trace/events.rst:602: WARNING: Unexpected indentation.
Documentation/trace/events.rst:622: WARNING: Block quote ends without a blank line; unexpected unindent.
Documentation/trace/events.rst:630: WARNING: Unexpected indentation.
I had to apply the following fixup (with rewording):
---- >8 ----
diff --git a/Documentation/trace/events.rst b/Documentation/trace/events.rst
index 0dc47516013331..c15f1d25d4a071 100644
--- a/Documentation/trace/events.rst
+++ b/Documentation/trace/events.rst
@@ -549,85 +549,89 @@ The following commands are supported:
- objtrace
This command provides a way to get the value of any object, The object
- can be obtained from the dynamic event(kprobe_event/uprobe_event) or the
- static event(tracepoint).
+ can be obtained from the dynamic event (kprobe_event/uprobe_event) or the
+ static event (tracepoint).
Usage:
- When using the kprobe event, only need to set the objtrace(a new trigger),
- we can get the value of the object. The object is from the setting of the
- kprobe event.
+ When using the kprobe event, by only need to set the objtrace (a new
+ trigger), we can get the value of object that is set by kprobe event.
- For example:
- For the function bio_add_page():
+ For example, for the function bio_add_page():
- int bio_add_page(struct bio *bio, struct page *page,
- unsigned int len, unsigned int offset)
+ .. code-block:: c
- Firstly, we can set the base of the object, thus the first string "arg1"
- stands for the value of the first parameter of this function bio_add_gage(),
+ int bio_add_page(struct bio *bio, struct page *page,
+ unsigned int len, unsigned int offset)
- # echo 'p bio_add_page arg1=$arg1' > ./kprobe_events
+ Firstly, we can set the base of the object as first parameter (arg1) to
+ to the function:
- Secondly, we can get the value dynamically based on above object.
+ .. code-block::
- find the offset of the bi_size in struct bio:
- $ gdb vmlinux
- (gdb) p &(((struct bio *)0)->bi_iter.bi_size)
- $1 = (unsigned int *) 0x28
+ # echo 'p bio_add_page arg1=$arg1' > ./kprobe_events
- # echo 'objtrace:add:arg1,0x28:u32:1 if comm == "cat"' > ./events/kprobes/ \
- p_bio_add_page_0/trigger
+ Secondly, we can get the value dynamically based on the object:
- # cd /sys/kernel/debug/tracing/
- # echo 'p bio_add_page arg1=$arg1' > ./kprobe_events
- # echo 'objtrace:add:arg1,0x28:u32:1 if comm == "cat"' > ./events/kprobes/p_bio_add_page_0/trigger
+ .. code-block::
- # du -sh /test.txt
- 12.0K /test.txt
+ find the offset of the bi_size in struct bio:
+ $ gdb vmlinux
+ (gdb) p &(((struct bio *)0)->bi_iter.bi_size)
+ $1 = (unsigned int *) 0x28
- # cat /test.txt > /dev/null
- # cat ./trace
- # tracer: nop
- #
- # entries-in-buffer/entries-written: 128/128 #P:4
- #
- # _-----=> irqs-off/BH-disabled
- # / _----=> need-resched
- # | / _---=> hardirq/softirq
- # || / _--=> preempt-depth
- # ||| / _-=> migrate-disable
- # |||| / delay
- # TASK-PID CPU# ||||| TIMESTAMP FUNCTION
- # | | | ||||| | |
- cat-117 [002] ...1. 1.602243: __bio_try_merge_page <-bio_add_page object:0xffff88811bee4000 value:0x0
- cat-117 [002] ...1. 1.602244: __bio_add_page <-bio_add_page object:0xffff88811bee4000 value:0x0
- cat-117 [002] ...2. 1.602244: bio_add_page <-ext4_mpage_readpages object:0xffff88811bee4000 value:0x1000
- cat-117 [002] ...1. 1.602245: __bio_try_merge_page <-bio_add_page object:0xffff88811bee4000 value:0x1000
- cat-117 [002] ...1. 1.602245: __bio_add_page <-bio_add_page object:0xffff88811bee4000 value:0x1000
- cat-117 [002] ...2. 1.602245: bio_add_page <-ext4_mpage_readpages object:0xffff88811bee4000 value:0x2000
- cat-117 [002] ...1. 1.602245: __bio_try_merge_page <-bio_add_page object:0xffff88811bee4000 value:0x2000
- cat-117 [002] ...1. 1.602245: __bio_add_page <-bio_add_page object:0xffff88811bee4000 value:0x2000
- cat-117 [002] ...1. 1.602245: submit_bio <-ext4_mpage_readpages object:0xffff88811bee4000 value:0x3000
- cat-117 [002] ...1. 1.602245: submit_bio_noacct <-ext4_mpage_readpages object:0xffff88811bee4000 value:0x3000
- cat-117 [002] ...1. 1.602246: __submit_bio <-submit_bio_noacct object:0xffff88811bee4000 value:0x3000
- cat-117 [002] ...1. 1.602246: submit_bio_checks <-__submit_bio object:0xffff88811bee4000 value:0x3000
- cat-117 [002] ...1. 1.602246: __cond_resched <-submit_bio_checks object:0xffff88811bee4000 value:0x3000
- cat-117 [002] ...1. 1.602246: should_fail_bio <-submit_bio_checks object:0xffff88811bee4000 value:0x3000
- cat-117 [002] ...1. 1.602246: blk_mq_submit_bio <-submit_bio_noacct object:0xffff88811bee4000 value:0x3000
- cat-117 [002] ...1. 1.602246: blk_attempt_plug_merge <-blk_mq_submit_bio object:0xffff88811bee4000 value:0x3000
- cat-117 [002] ...1. 1.602246: blk_mq_sched_bio_merge <-blk_mq_submit_bio object:0xffff88811bee4000 value:0x3000
- cat-117 [002] ...1. 1.602247: __rcu_read_lock <-blk_mq_submit_bio object:0xffff88811bee4000 value:0x3000
- cat-117 [002] ...1. 1.602247: __rcu_read_unlock <-blk_mq_submit_bio object:0xffff88811bee4000 value:0x3000
- cat-117 [002] ...1. 1.602247: __blk_mq_alloc_requests <-blk_mq_submit_bio object:0xffff88811bee4000 value:0x3000
- <idle>-0 [002] d..3. 1.602298: bio_endio <-blk_update_request object:0xffff88811bee4000 value:0x0
- <idle>-0 [002] d..3. 1.602298: mpage_end_io <-blk_update_request object:0xffff88811bee4000 value:0x0
- <idle>-0 [002] d..3. 1.602298: __read_end_io <-blk_update_request object:0xffff88811bee4000 value:0x0
- <idle>-0 [002] d..3. 1.602300: bio_put <-blk_update_request object:0xffff88811bee4000 value:0x0
- <idle>-0 [002] d..3. 1.602300: bio_free <-blk_update_request object:0xffff88811bee4000 value:0x0
- <idle>-0 [002] d..3. 1.602300: mempool_free <-blk_update_request object:0xffff88811bee4000 value:0x0
- <idle>-0 [002] d..3. 1.602300: mempool_free_slab <-blk_update_request object:0xffff88811bee4000 value:0x0
- <idle>-0 [002] d..3. 1.602300: kmem_cache_free <-blk_update_request object:0xffff88811bee4000 value:0x0
- ...
+ # echo 'objtrace:add:arg1,0x28:u32:1 if comm == "cat"' > ./events/kprobes/ \
+ p_bio_add_page_0/trigger
+
+ # cd /sys/kernel/debug/tracing/
+ # echo 'p bio_add_page arg1=$arg1' > ./kprobe_events
+ # echo 'objtrace:add:arg1,0x28:u32:1 if comm == "cat"' > ./events/kprobes/p_bio_add_page_0/trigger
+
+ # du -sh /test.txt
+ 12.0K /test.txt
+
+ # cat /test.txt > /dev/null
+ # cat ./trace
+ # tracer: nop
+ #
+ # entries-in-buffer/entries-written: 128/128 #P:4
+ #
+ # _-----=> irqs-off/BH-disabled
+ # / _----=> need-resched
+ # | / _---=> hardirq/softirq
+ # || / _--=> preempt-depth
+ # ||| / _-=> migrate-disable
+ # |||| / delay
+ # TASK-PID CPU# ||||| TIMESTAMP FUNCTION
+ # | | | ||||| | |
+ cat-117 [002] ...1. 1.602243: __bio_try_merge_page <-bio_add_page object:0xffff88811bee4000 value:0x0
+ cat-117 [002] ...1. 1.602244: __bio_add_page <-bio_add_page object:0xffff88811bee4000 value:0x0
+ cat-117 [002] ...2. 1.602244: bio_add_page <-ext4_mpage_readpages object:0xffff88811bee4000 value:0x1000
+ cat-117 [002] ...1. 1.602245: __bio_try_merge_page <-bio_add_page object:0xffff88811bee4000 value:0x1000
+ cat-117 [002] ...1. 1.602245: __bio_add_page <-bio_add_page object:0xffff88811bee4000 value:0x1000
+ cat-117 [002] ...2. 1.602245: bio_add_page <-ext4_mpage_readpages object:0xffff88811bee4000 value:0x2000
+ cat-117 [002] ...1. 1.602245: __bio_try_merge_page <-bio_add_page object:0xffff88811bee4000 value:0x2000
+ cat-117 [002] ...1. 1.602245: __bio_add_page <-bio_add_page object:0xffff88811bee4000 value:0x2000
+ cat-117 [002] ...1. 1.602245: submit_bio <-ext4_mpage_readpages object:0xffff88811bee4000 value:0x3000
+ cat-117 [002] ...1. 1.602245: submit_bio_noacct <-ext4_mpage_readpages object:0xffff88811bee4000 value:0x3000
+ cat-117 [002] ...1. 1.602246: __submit_bio <-submit_bio_noacct object:0xffff88811bee4000 value:0x3000
+ cat-117 [002] ...1. 1.602246: submit_bio_checks <-__submit_bio object:0xffff88811bee4000 value:0x3000
+ cat-117 [002] ...1. 1.602246: __cond_resched <-submit_bio_checks object:0xffff88811bee4000 value:0x3000
+ cat-117 [002] ...1. 1.602246: should_fail_bio <-submit_bio_checks object:0xffff88811bee4000 value:0x3000
+ cat-117 [002] ...1. 1.602246: blk_mq_submit_bio <-submit_bio_noacct object:0xffff88811bee4000 value:0x3000
+ cat-117 [002] ...1. 1.602246: blk_attempt_plug_merge <-blk_mq_submit_bio object:0xffff88811bee4000 value:0x3000
+ cat-117 [002] ...1. 1.602246: blk_mq_sched_bio_merge <-blk_mq_submit_bio object:0xffff88811bee4000 value:0x3000
+ cat-117 [002] ...1. 1.602247: __rcu_read_lock <-blk_mq_submit_bio object:0xffff88811bee4000 value:0x3000
+ cat-117 [002] ...1. 1.602247: __rcu_read_unlock <-blk_mq_submit_bio object:0xffff88811bee4000 value:0x3000
+ cat-117 [002] ...1. 1.602247: __blk_mq_alloc_requests <-blk_mq_submit_bio object:0xffff88811bee4000 value:0x3000
+ <idle>-0 [002] d..3. 1.602298: bio_endio <-blk_update_request object:0xffff88811bee4000 value:0x0
+ <idle>-0 [002] d..3. 1.602298: mpage_end_io <-blk_update_request object:0xffff88811bee4000 value:0x0
+ <idle>-0 [002] d..3. 1.602298: __read_end_io <-blk_update_request object:0xffff88811bee4000 value:0x0
+ <idle>-0 [002] d..3. 1.602300: bio_put <-blk_update_request object:0xffff88811bee4000 value:0x0
+ <idle>-0 [002] d..3. 1.602300: bio_free <-blk_update_request object:0xffff88811bee4000 value:0x0
+ <idle>-0 [002] d..3. 1.602300: mempool_free <-blk_update_request object:0xffff88811bee4000 value:0x0
+ <idle>-0 [002] d..3. 1.602300: mempool_free_slab <-blk_update_request object:0xffff88811bee4000 value:0x0
+ <idle>-0 [002] d..3. 1.602300: kmem_cache_free <-blk_update_request object:0xffff88811bee4000 value:0x0
+ ...
7. In-kernel trace event API
============================
Thanks.
--
An old man doll... just what I always wanted! - Clara
^ permalink raw reply related [flat|nested] 12+ messages in thread
* Re: [PATCH v13 4/4] Documentation: trace/objtrace: Add documentation for objtrace
2022-06-27 2:14 ` Bagas Sanjaya
@ 2022-06-27 7:45 ` Jeff Xie
2022-06-28 1:37 ` Jeff Xie
0 siblings, 1 reply; 12+ messages in thread
From: Jeff Xie @ 2022-06-27 7:45 UTC (permalink / raw)
To: Bagas Sanjaya
Cc: Steven Rostedt, mingo, Masami Hiramatsu, Tom Zanussi,
linux-kernel, linux-kselftest, Shuah Khan, linux-doc,
Jonathan Corbet, Song Chen
Hi,
On Mon, Jun 27, 2022 at 10:14 AM Bagas Sanjaya <bagasdotme@gmail.com> wrote:
>
> On Sun, Jun 26, 2022 at 10:56:04AM +0800, Jeff Xie wrote:
> > Added documentation explaining how to use objtrace trigger to get the value
> > of the object.
> >
>
> Write "Add documentation..." instead.
Thanks, I will change it.
> > +- objtrace
> > +
> > + This command provides a way to get the value of any object, The object
> > + can be obtained from the dynamic event(kprobe_event/uprobe_event) or the
> > + static event(tracepoint).
> > +
> > + Usage:
> > + When using the kprobe event, only need to set the objtrace(a new trigger),
> > + we can get the value of the object. The object is from the setting of the
> > + kprobe event.
> > +
>
> Did you mean "the object value can be obtained by only needing to set the
> objtrace?"
Yes, that's what it means.
> > + For example:
> > + For the function bio_add_page():
> > +
> > + int bio_add_page(struct bio *bio, struct page *page,
> > + unsigned int len, unsigned int offset)
> > +
> > + Firstly, we can set the base of the object, thus the first string "arg1"
> > + stands for the value of the first parameter of this function bio_add_gage(),
> > +
> > + # echo 'p bio_add_page arg1=$arg1' > ./kprobe_events
> > +
>
> Did you mean "the first parameter (arg1) is the parameter value of function
> that is passed to kprobe_event, in this case the object base"?
Yes, that's what it means.
> > + Secondly, we can get the value dynamically based on above object.
> > +
> > + find the offset of the bi_size in struct bio:
> > + $ gdb vmlinux
> > + (gdb) p &(((struct bio *)0)->bi_iter.bi_size)
> > + $1 = (unsigned int *) 0x28
> > +
> > + # echo 'objtrace:add:arg1,0x28:u32:1 if comm == "cat"' > ./events/kprobes/ \
> > + p_bio_add_page_0/trigger
> > +
> > + # cd /sys/kernel/debug/tracing/
> > + # echo 'p bio_add_page arg1=$arg1' > ./kprobe_events
> > + # echo 'objtrace:add:arg1,0x28:u32:1 if comm == "cat"' > ./events/kprobes/p_bio_add_page_0/trigger
> > +
> > + # du -sh /test.txt
> > + 12.0K /test.txt
> > +
> > + # cat /test.txt > /dev/null
> > + # cat ./trace
> > + # tracer: nop
> > + #
> > + # entries-in-buffer/entries-written: 128/128 #P:4
> > + #
> > + # _-----=> irqs-off/BH-disabled
> > + # / _----=> need-resched
> > + # | / _---=> hardirq/softirq
> > + # || / _--=> preempt-depth
> > + # ||| / _-=> migrate-disable
> > + # |||| / delay
> > + # TASK-PID CPU# ||||| TIMESTAMP FUNCTION
> > + # | | | ||||| | |
> > + cat-117 [002] ...1. 1.602243: __bio_try_merge_page <-bio_add_page object:0xffff88811bee4000 value:0x0
> > + cat-117 [002] ...1. 1.602244: __bio_add_page <-bio_add_page object:0xffff88811bee4000 value:0x0
> > + cat-117 [002] ...2. 1.602244: bio_add_page <-ext4_mpage_readpages object:0xffff88811bee4000 value:0x1000
> > + cat-117 [002] ...1. 1.602245: __bio_try_merge_page <-bio_add_page object:0xffff88811bee4000 value:0x1000
> > + cat-117 [002] ...1. 1.602245: __bio_add_page <-bio_add_page object:0xffff88811bee4000 value:0x1000
> > + cat-117 [002] ...2. 1.602245: bio_add_page <-ext4_mpage_readpages object:0xffff88811bee4000 value:0x2000
> > + cat-117 [002] ...1. 1.602245: __bio_try_merge_page <-bio_add_page object:0xffff88811bee4000 value:0x2000
> > + cat-117 [002] ...1. 1.602245: __bio_add_page <-bio_add_page object:0xffff88811bee4000 value:0x2000
> > + cat-117 [002] ...1. 1.602245: submit_bio <-ext4_mpage_readpages object:0xffff88811bee4000 value:0x3000
> > + cat-117 [002] ...1. 1.602245: submit_bio_noacct <-ext4_mpage_readpages object:0xffff88811bee4000 value:0x3000
> > + cat-117 [002] ...1. 1.602246: __submit_bio <-submit_bio_noacct object:0xffff88811bee4000 value:0x3000
> > + cat-117 [002] ...1. 1.602246: submit_bio_checks <-__submit_bio object:0xffff88811bee4000 value:0x3000
> > + cat-117 [002] ...1. 1.602246: __cond_resched <-submit_bio_checks object:0xffff88811bee4000 value:0x3000
> > + cat-117 [002] ...1. 1.602246: should_fail_bio <-submit_bio_checks object:0xffff88811bee4000 value:0x3000
> > + cat-117 [002] ...1. 1.602246: blk_mq_submit_bio <-submit_bio_noacct object:0xffff88811bee4000 value:0x3000
> > + cat-117 [002] ...1. 1.602246: blk_attempt_plug_merge <-blk_mq_submit_bio object:0xffff88811bee4000 value:0x3000
> > + cat-117 [002] ...1. 1.602246: blk_mq_sched_bio_merge <-blk_mq_submit_bio object:0xffff88811bee4000 value:0x3000
> > + cat-117 [002] ...1. 1.602247: __rcu_read_lock <-blk_mq_submit_bio object:0xffff88811bee4000 value:0x3000
> > + cat-117 [002] ...1. 1.602247: __rcu_read_unlock <-blk_mq_submit_bio object:0xffff88811bee4000 value:0x3000
> > + cat-117 [002] ...1. 1.602247: __blk_mq_alloc_requests <-blk_mq_submit_bio object:0xffff88811bee4000 value:0x3000
> > + <idle>-0 [002] d..3. 1.602298: bio_endio <-blk_update_request object:0xffff88811bee4000 value:0x0
> > + <idle>-0 [002] d..3. 1.602298: mpage_end_io <-blk_update_request object:0xffff88811bee4000 value:0x0
> > + <idle>-0 [002] d..3. 1.602298: __read_end_io <-blk_update_request object:0xffff88811bee4000 value:0x0
> > + <idle>-0 [002] d..3. 1.602300: bio_put <-blk_update_request object:0xffff88811bee4000 value:0x0
> > + <idle>-0 [002] d..3. 1.602300: bio_free <-blk_update_request object:0xffff88811bee4000 value:0x0
> > + <idle>-0 [002] d..3. 1.602300: mempool_free <-blk_update_request object:0xffff88811bee4000 value:0x0
> > + <idle>-0 [002] d..3. 1.602300: mempool_free_slab <-blk_update_request object:0xffff88811bee4000 value:0x0
> > + <idle>-0 [002] d..3. 1.602300: kmem_cache_free <-blk_update_request object:0xffff88811bee4000 value:0x0
> > + ...
> > +
>
> The output is messy, because for code example and output, literal code
> blocks aren't used, hence trigger new warnings:
>
> Documentation/trace/events.rst:564: WARNING: Inline emphasis start-string without end-string.
> Documentation/trace/events.rst:564: WARNING: Inline emphasis start-string without end-string.
> Documentation/trace/events.rst:573: WARNING: Inline emphasis start-string without end-string.
> Documentation/trace/events.rst:573: WARNING: Inline emphasis start-string without end-string.
> Documentation/trace/events.rst:602: WARNING: Unexpected indentation.
> Documentation/trace/events.rst:622: WARNING: Block quote ends without a blank line; unexpected unindent.
> Documentation/trace/events.rst:630: WARNING: Unexpected indentation.
>
> I had to apply the following fixup (with rewording):
Thank you so much for your help, It looks better ;-)
> ---- >8 ----
>
> diff --git a/Documentation/trace/events.rst b/Documentation/trace/events.rst
> index 0dc47516013331..c15f1d25d4a071 100644
> --- a/Documentation/trace/events.rst
> +++ b/Documentation/trace/events.rst
> @@ -549,85 +549,89 @@ The following commands are supported:
> - objtrace
>
> This command provides a way to get the value of any object, The object
> - can be obtained from the dynamic event(kprobe_event/uprobe_event) or the
> - static event(tracepoint).
> + can be obtained from the dynamic event (kprobe_event/uprobe_event) or the
> + static event (tracepoint).
>
> Usage:
> - When using the kprobe event, only need to set the objtrace(a new trigger),
> - we can get the value of the object. The object is from the setting of the
> - kprobe event.
> + When using the kprobe event, by only need to set the objtrace (a new
> + trigger), we can get the value of object that is set by kprobe event.
>
> - For example:
> - For the function bio_add_page():
> + For example, for the function bio_add_page():
>
> - int bio_add_page(struct bio *bio, struct page *page,
> - unsigned int len, unsigned int offset)
> + .. code-block:: c
>
> - Firstly, we can set the base of the object, thus the first string "arg1"
> - stands for the value of the first parameter of this function bio_add_gage(),
> + int bio_add_page(struct bio *bio, struct page *page,
> + unsigned int len, unsigned int offset)
>
> - # echo 'p bio_add_page arg1=$arg1' > ./kprobe_events
> + Firstly, we can set the base of the object as first parameter (arg1) to
> + to the function:
>
> - Secondly, we can get the value dynamically based on above object.
> + .. code-block::
>
> - find the offset of the bi_size in struct bio:
> - $ gdb vmlinux
> - (gdb) p &(((struct bio *)0)->bi_iter.bi_size)
> - $1 = (unsigned int *) 0x28
> + # echo 'p bio_add_page arg1=$arg1' > ./kprobe_events
>
> - # echo 'objtrace:add:arg1,0x28:u32:1 if comm == "cat"' > ./events/kprobes/ \
> - p_bio_add_page_0/trigger
> + Secondly, we can get the value dynamically based on the object:
>
> - # cd /sys/kernel/debug/tracing/
> - # echo 'p bio_add_page arg1=$arg1' > ./kprobe_events
> - # echo 'objtrace:add:arg1,0x28:u32:1 if comm == "cat"' > ./events/kprobes/p_bio_add_page_0/trigger
> + .. code-block::
>
> - # du -sh /test.txt
> - 12.0K /test.txt
> + find the offset of the bi_size in struct bio:
> + $ gdb vmlinux
> + (gdb) p &(((struct bio *)0)->bi_iter.bi_size)
> + $1 = (unsigned int *) 0x28
>
> - # cat /test.txt > /dev/null
> - # cat ./trace
> - # tracer: nop
> - #
> - # entries-in-buffer/entries-written: 128/128 #P:4
> - #
> - # _-----=> irqs-off/BH-disabled
> - # / _----=> need-resched
> - # | / _---=> hardirq/softirq
> - # || / _--=> preempt-depth
> - # ||| / _-=> migrate-disable
> - # |||| / delay
> - # TASK-PID CPU# ||||| TIMESTAMP FUNCTION
> - # | | | ||||| | |
> - cat-117 [002] ...1. 1.602243: __bio_try_merge_page <-bio_add_page object:0xffff88811bee4000 value:0x0
> - cat-117 [002] ...1. 1.602244: __bio_add_page <-bio_add_page object:0xffff88811bee4000 value:0x0
> - cat-117 [002] ...2. 1.602244: bio_add_page <-ext4_mpage_readpages object:0xffff88811bee4000 value:0x1000
> - cat-117 [002] ...1. 1.602245: __bio_try_merge_page <-bio_add_page object:0xffff88811bee4000 value:0x1000
> - cat-117 [002] ...1. 1.602245: __bio_add_page <-bio_add_page object:0xffff88811bee4000 value:0x1000
> - cat-117 [002] ...2. 1.602245: bio_add_page <-ext4_mpage_readpages object:0xffff88811bee4000 value:0x2000
> - cat-117 [002] ...1. 1.602245: __bio_try_merge_page <-bio_add_page object:0xffff88811bee4000 value:0x2000
> - cat-117 [002] ...1. 1.602245: __bio_add_page <-bio_add_page object:0xffff88811bee4000 value:0x2000
> - cat-117 [002] ...1. 1.602245: submit_bio <-ext4_mpage_readpages object:0xffff88811bee4000 value:0x3000
> - cat-117 [002] ...1. 1.602245: submit_bio_noacct <-ext4_mpage_readpages object:0xffff88811bee4000 value:0x3000
> - cat-117 [002] ...1. 1.602246: __submit_bio <-submit_bio_noacct object:0xffff88811bee4000 value:0x3000
> - cat-117 [002] ...1. 1.602246: submit_bio_checks <-__submit_bio object:0xffff88811bee4000 value:0x3000
> - cat-117 [002] ...1. 1.602246: __cond_resched <-submit_bio_checks object:0xffff88811bee4000 value:0x3000
> - cat-117 [002] ...1. 1.602246: should_fail_bio <-submit_bio_checks object:0xffff88811bee4000 value:0x3000
> - cat-117 [002] ...1. 1.602246: blk_mq_submit_bio <-submit_bio_noacct object:0xffff88811bee4000 value:0x3000
> - cat-117 [002] ...1. 1.602246: blk_attempt_plug_merge <-blk_mq_submit_bio object:0xffff88811bee4000 value:0x3000
> - cat-117 [002] ...1. 1.602246: blk_mq_sched_bio_merge <-blk_mq_submit_bio object:0xffff88811bee4000 value:0x3000
> - cat-117 [002] ...1. 1.602247: __rcu_read_lock <-blk_mq_submit_bio object:0xffff88811bee4000 value:0x3000
> - cat-117 [002] ...1. 1.602247: __rcu_read_unlock <-blk_mq_submit_bio object:0xffff88811bee4000 value:0x3000
> - cat-117 [002] ...1. 1.602247: __blk_mq_alloc_requests <-blk_mq_submit_bio object:0xffff88811bee4000 value:0x3000
> - <idle>-0 [002] d..3. 1.602298: bio_endio <-blk_update_request object:0xffff88811bee4000 value:0x0
> - <idle>-0 [002] d..3. 1.602298: mpage_end_io <-blk_update_request object:0xffff88811bee4000 value:0x0
> - <idle>-0 [002] d..3. 1.602298: __read_end_io <-blk_update_request object:0xffff88811bee4000 value:0x0
> - <idle>-0 [002] d..3. 1.602300: bio_put <-blk_update_request object:0xffff88811bee4000 value:0x0
> - <idle>-0 [002] d..3. 1.602300: bio_free <-blk_update_request object:0xffff88811bee4000 value:0x0
> - <idle>-0 [002] d..3. 1.602300: mempool_free <-blk_update_request object:0xffff88811bee4000 value:0x0
> - <idle>-0 [002] d..3. 1.602300: mempool_free_slab <-blk_update_request object:0xffff88811bee4000 value:0x0
> - <idle>-0 [002] d..3. 1.602300: kmem_cache_free <-blk_update_request object:0xffff88811bee4000 value:0x0
> - ...
> + # echo 'objtrace:add:arg1,0x28:u32:1 if comm == "cat"' > ./events/kprobes/ \
> + p_bio_add_page_0/trigger
> +
> + # cd /sys/kernel/debug/tracing/
> + # echo 'p bio_add_page arg1=$arg1' > ./kprobe_events
> + # echo 'objtrace:add:arg1,0x28:u32:1 if comm == "cat"' > ./events/kprobes/p_bio_add_page_0/trigger
> +
> + # du -sh /test.txt
> + 12.0K /test.txt
> +
> + # cat /test.txt > /dev/null
> + # cat ./trace
> + # tracer: nop
> + #
> + # entries-in-buffer/entries-written: 128/128 #P:4
> + #
> + # _-----=> irqs-off/BH-disabled
> + # / _----=> need-resched
> + # | / _---=> hardirq/softirq
> + # || / _--=> preempt-depth
> + # ||| / _-=> migrate-disable
> + # |||| / delay
> + # TASK-PID CPU# ||||| TIMESTAMP FUNCTION
> + # | | | ||||| | |
> + cat-117 [002] ...1. 1.602243: __bio_try_merge_page <-bio_add_page object:0xffff88811bee4000 value:0x0
> + cat-117 [002] ...1. 1.602244: __bio_add_page <-bio_add_page object:0xffff88811bee4000 value:0x0
> + cat-117 [002] ...2. 1.602244: bio_add_page <-ext4_mpage_readpages object:0xffff88811bee4000 value:0x1000
> + cat-117 [002] ...1. 1.602245: __bio_try_merge_page <-bio_add_page object:0xffff88811bee4000 value:0x1000
> + cat-117 [002] ...1. 1.602245: __bio_add_page <-bio_add_page object:0xffff88811bee4000 value:0x1000
> + cat-117 [002] ...2. 1.602245: bio_add_page <-ext4_mpage_readpages object:0xffff88811bee4000 value:0x2000
> + cat-117 [002] ...1. 1.602245: __bio_try_merge_page <-bio_add_page object:0xffff88811bee4000 value:0x2000
> + cat-117 [002] ...1. 1.602245: __bio_add_page <-bio_add_page object:0xffff88811bee4000 value:0x2000
> + cat-117 [002] ...1. 1.602245: submit_bio <-ext4_mpage_readpages object:0xffff88811bee4000 value:0x3000
> + cat-117 [002] ...1. 1.602245: submit_bio_noacct <-ext4_mpage_readpages object:0xffff88811bee4000 value:0x3000
> + cat-117 [002] ...1. 1.602246: __submit_bio <-submit_bio_noacct object:0xffff88811bee4000 value:0x3000
> + cat-117 [002] ...1. 1.602246: submit_bio_checks <-__submit_bio object:0xffff88811bee4000 value:0x3000
> + cat-117 [002] ...1. 1.602246: __cond_resched <-submit_bio_checks object:0xffff88811bee4000 value:0x3000
> + cat-117 [002] ...1. 1.602246: should_fail_bio <-submit_bio_checks object:0xffff88811bee4000 value:0x3000
> + cat-117 [002] ...1. 1.602246: blk_mq_submit_bio <-submit_bio_noacct object:0xffff88811bee4000 value:0x3000
> + cat-117 [002] ...1. 1.602246: blk_attempt_plug_merge <-blk_mq_submit_bio object:0xffff88811bee4000 value:0x3000
> + cat-117 [002] ...1. 1.602246: blk_mq_sched_bio_merge <-blk_mq_submit_bio object:0xffff88811bee4000 value:0x3000
> + cat-117 [002] ...1. 1.602247: __rcu_read_lock <-blk_mq_submit_bio object:0xffff88811bee4000 value:0x3000
> + cat-117 [002] ...1. 1.602247: __rcu_read_unlock <-blk_mq_submit_bio object:0xffff88811bee4000 value:0x3000
> + cat-117 [002] ...1. 1.602247: __blk_mq_alloc_requests <-blk_mq_submit_bio object:0xffff88811bee4000 value:0x3000
> + <idle>-0 [002] d..3. 1.602298: bio_endio <-blk_update_request object:0xffff88811bee4000 value:0x0
> + <idle>-0 [002] d..3. 1.602298: mpage_end_io <-blk_update_request object:0xffff88811bee4000 value:0x0
> + <idle>-0 [002] d..3. 1.602298: __read_end_io <-blk_update_request object:0xffff88811bee4000 value:0x0
> + <idle>-0 [002] d..3. 1.602300: bio_put <-blk_update_request object:0xffff88811bee4000 value:0x0
> + <idle>-0 [002] d..3. 1.602300: bio_free <-blk_update_request object:0xffff88811bee4000 value:0x0
> + <idle>-0 [002] d..3. 1.602300: mempool_free <-blk_update_request object:0xffff88811bee4000 value:0x0
> + <idle>-0 [002] d..3. 1.602300: mempool_free_slab <-blk_update_request object:0xffff88811bee4000 value:0x0
> + <idle>-0 [002] d..3. 1.602300: kmem_cache_free <-blk_update_request object:0xffff88811bee4000 value:0x0
> + ...
>
> 7. In-kernel trace event API
> ============================
>
>
> Thanks.
>
> --
> An old man doll... just what I always wanted! - Clara
Thanks,
JeffXie
^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [PATCH v13 4/4] Documentation: trace/objtrace: Add documentation for objtrace
2022-06-27 7:45 ` Jeff Xie
@ 2022-06-28 1:37 ` Jeff Xie
2022-06-28 2:31 ` Bagas Sanjaya
0 siblings, 1 reply; 12+ messages in thread
From: Jeff Xie @ 2022-06-28 1:37 UTC (permalink / raw)
To: Masami Hiramatsu
Cc: Steven Rostedt, mingo, Tom Zanussi, linux-kernel, linux-kselftest,
Shuah Khan, linux-doc, Jonathan Corbet, Song Chen, Bagas Sanjaya
Hi Masami,
I would like to ask if I change the document like "Bagas Sanjaya"
rewording in the next version.
I don't know if I can add your Reviewed-by again, I don't know the
rules very well ;-)
On Mon, Jun 27, 2022 at 3:45 PM Jeff Xie <xiehuan09@gmail.com> wrote:
>
> Hi,
>
> On Mon, Jun 27, 2022 at 10:14 AM Bagas Sanjaya <bagasdotme@gmail.com> wrote:
> >
> > On Sun, Jun 26, 2022 at 10:56:04AM +0800, Jeff Xie wrote:
> > > Added documentation explaining how to use objtrace trigger to get the value
> > > of the object.
> > >
> >
> > Write "Add documentation..." instead.
>
> Thanks, I will change it.
>
> > > +- objtrace
> > > +
> > > + This command provides a way to get the value of any object, The object
> > > + can be obtained from the dynamic event(kprobe_event/uprobe_event) or the
> > > + static event(tracepoint).
> > > +
> > > + Usage:
> > > + When using the kprobe event, only need to set the objtrace(a new trigger),
> > > + we can get the value of the object. The object is from the setting of the
> > > + kprobe event.
> > > +
> >
> > Did you mean "the object value can be obtained by only needing to set the
> > objtrace?"
>
> Yes, that's what it means.
>
> > > + For example:
> > > + For the function bio_add_page():
> > > +
> > > + int bio_add_page(struct bio *bio, struct page *page,
> > > + unsigned int len, unsigned int offset)
> > > +
> > > + Firstly, we can set the base of the object, thus the first string "arg1"
> > > + stands for the value of the first parameter of this function bio_add_gage(),
> > > +
> > > + # echo 'p bio_add_page arg1=$arg1' > ./kprobe_events
> > > +
> >
> > Did you mean "the first parameter (arg1) is the parameter value of function
> > that is passed to kprobe_event, in this case the object base"?
>
> Yes, that's what it means.
>
> > > + Secondly, we can get the value dynamically based on above object.
> > > +
> > > + find the offset of the bi_size in struct bio:
> > > + $ gdb vmlinux
> > > + (gdb) p &(((struct bio *)0)->bi_iter.bi_size)
> > > + $1 = (unsigned int *) 0x28
> > > +
> > > + # echo 'objtrace:add:arg1,0x28:u32:1 if comm == "cat"' > ./events/kprobes/ \
> > > + p_bio_add_page_0/trigger
> > > +
> > > + # cd /sys/kernel/debug/tracing/
> > > + # echo 'p bio_add_page arg1=$arg1' > ./kprobe_events
> > > + # echo 'objtrace:add:arg1,0x28:u32:1 if comm == "cat"' > ./events/kprobes/p_bio_add_page_0/trigger
> > > +
> > > + # du -sh /test.txt
> > > + 12.0K /test.txt
> > > +
> > > + # cat /test.txt > /dev/null
> > > + # cat ./trace
> > > + # tracer: nop
> > > + #
> > > + # entries-in-buffer/entries-written: 128/128 #P:4
> > > + #
> > > + # _-----=> irqs-off/BH-disabled
> > > + # / _----=> need-resched
> > > + # | / _---=> hardirq/softirq
> > > + # || / _--=> preempt-depth
> > > + # ||| / _-=> migrate-disable
> > > + # |||| / delay
> > > + # TASK-PID CPU# ||||| TIMESTAMP FUNCTION
> > > + # | | | ||||| | |
> > > + cat-117 [002] ...1. 1.602243: __bio_try_merge_page <-bio_add_page object:0xffff88811bee4000 value:0x0
> > > + cat-117 [002] ...1. 1.602244: __bio_add_page <-bio_add_page object:0xffff88811bee4000 value:0x0
> > > + cat-117 [002] ...2. 1.602244: bio_add_page <-ext4_mpage_readpages object:0xffff88811bee4000 value:0x1000
> > > + cat-117 [002] ...1. 1.602245: __bio_try_merge_page <-bio_add_page object:0xffff88811bee4000 value:0x1000
> > > + cat-117 [002] ...1. 1.602245: __bio_add_page <-bio_add_page object:0xffff88811bee4000 value:0x1000
> > > + cat-117 [002] ...2. 1.602245: bio_add_page <-ext4_mpage_readpages object:0xffff88811bee4000 value:0x2000
> > > + cat-117 [002] ...1. 1.602245: __bio_try_merge_page <-bio_add_page object:0xffff88811bee4000 value:0x2000
> > > + cat-117 [002] ...1. 1.602245: __bio_add_page <-bio_add_page object:0xffff88811bee4000 value:0x2000
> > > + cat-117 [002] ...1. 1.602245: submit_bio <-ext4_mpage_readpages object:0xffff88811bee4000 value:0x3000
> > > + cat-117 [002] ...1. 1.602245: submit_bio_noacct <-ext4_mpage_readpages object:0xffff88811bee4000 value:0x3000
> > > + cat-117 [002] ...1. 1.602246: __submit_bio <-submit_bio_noacct object:0xffff88811bee4000 value:0x3000
> > > + cat-117 [002] ...1. 1.602246: submit_bio_checks <-__submit_bio object:0xffff88811bee4000 value:0x3000
> > > + cat-117 [002] ...1. 1.602246: __cond_resched <-submit_bio_checks object:0xffff88811bee4000 value:0x3000
> > > + cat-117 [002] ...1. 1.602246: should_fail_bio <-submit_bio_checks object:0xffff88811bee4000 value:0x3000
> > > + cat-117 [002] ...1. 1.602246: blk_mq_submit_bio <-submit_bio_noacct object:0xffff88811bee4000 value:0x3000
> > > + cat-117 [002] ...1. 1.602246: blk_attempt_plug_merge <-blk_mq_submit_bio object:0xffff88811bee4000 value:0x3000
> > > + cat-117 [002] ...1. 1.602246: blk_mq_sched_bio_merge <-blk_mq_submit_bio object:0xffff88811bee4000 value:0x3000
> > > + cat-117 [002] ...1. 1.602247: __rcu_read_lock <-blk_mq_submit_bio object:0xffff88811bee4000 value:0x3000
> > > + cat-117 [002] ...1. 1.602247: __rcu_read_unlock <-blk_mq_submit_bio object:0xffff88811bee4000 value:0x3000
> > > + cat-117 [002] ...1. 1.602247: __blk_mq_alloc_requests <-blk_mq_submit_bio object:0xffff88811bee4000 value:0x3000
> > > + <idle>-0 [002] d..3. 1.602298: bio_endio <-blk_update_request object:0xffff88811bee4000 value:0x0
> > > + <idle>-0 [002] d..3. 1.602298: mpage_end_io <-blk_update_request object:0xffff88811bee4000 value:0x0
> > > + <idle>-0 [002] d..3. 1.602298: __read_end_io <-blk_update_request object:0xffff88811bee4000 value:0x0
> > > + <idle>-0 [002] d..3. 1.602300: bio_put <-blk_update_request object:0xffff88811bee4000 value:0x0
> > > + <idle>-0 [002] d..3. 1.602300: bio_free <-blk_update_request object:0xffff88811bee4000 value:0x0
> > > + <idle>-0 [002] d..3. 1.602300: mempool_free <-blk_update_request object:0xffff88811bee4000 value:0x0
> > > + <idle>-0 [002] d..3. 1.602300: mempool_free_slab <-blk_update_request object:0xffff88811bee4000 value:0x0
> > > + <idle>-0 [002] d..3. 1.602300: kmem_cache_free <-blk_update_request object:0xffff88811bee4000 value:0x0
> > > + ...
> > > +
> >
> > The output is messy, because for code example and output, literal code
> > blocks aren't used, hence trigger new warnings:
> >
> > Documentation/trace/events.rst:564: WARNING: Inline emphasis start-string without end-string.
> > Documentation/trace/events.rst:564: WARNING: Inline emphasis start-string without end-string.
> > Documentation/trace/events.rst:573: WARNING: Inline emphasis start-string without end-string.
> > Documentation/trace/events.rst:573: WARNING: Inline emphasis start-string without end-string.
> > Documentation/trace/events.rst:602: WARNING: Unexpected indentation.
> > Documentation/trace/events.rst:622: WARNING: Block quote ends without a blank line; unexpected unindent.
> > Documentation/trace/events.rst:630: WARNING: Unexpected indentation.
> >
> > I had to apply the following fixup (with rewording):
>
> Thank you so much for your help, It looks better ;-)
>
> > ---- >8 ----
> >
> > diff --git a/Documentation/trace/events.rst b/Documentation/trace/events.rst
> > index 0dc47516013331..c15f1d25d4a071 100644
> > --- a/Documentation/trace/events.rst
> > +++ b/Documentation/trace/events.rst
> > @@ -549,85 +549,89 @@ The following commands are supported:
> > - objtrace
> >
> > This command provides a way to get the value of any object, The object
> > - can be obtained from the dynamic event(kprobe_event/uprobe_event) or the
> > - static event(tracepoint).
> > + can be obtained from the dynamic event (kprobe_event/uprobe_event) or the
> > + static event (tracepoint).
> >
> > Usage:
> > - When using the kprobe event, only need to set the objtrace(a new trigger),
> > - we can get the value of the object. The object is from the setting of the
> > - kprobe event.
> > + When using the kprobe event, by only need to set the objtrace (a new
> > + trigger), we can get the value of object that is set by kprobe event.
> >
> > - For example:
> > - For the function bio_add_page():
> > + For example, for the function bio_add_page():
> >
> > - int bio_add_page(struct bio *bio, struct page *page,
> > - unsigned int len, unsigned int offset)
> > + .. code-block:: c
> >
> > - Firstly, we can set the base of the object, thus the first string "arg1"
> > - stands for the value of the first parameter of this function bio_add_gage(),
> > + int bio_add_page(struct bio *bio, struct page *page,
> > + unsigned int len, unsigned int offset)
> >
> > - # echo 'p bio_add_page arg1=$arg1' > ./kprobe_events
> > + Firstly, we can set the base of the object as first parameter (arg1) to
> > + to the function:
> >
> > - Secondly, we can get the value dynamically based on above object.
> > + .. code-block::
> >
> > - find the offset of the bi_size in struct bio:
> > - $ gdb vmlinux
> > - (gdb) p &(((struct bio *)0)->bi_iter.bi_size)
> > - $1 = (unsigned int *) 0x28
> > + # echo 'p bio_add_page arg1=$arg1' > ./kprobe_events
> >
> > - # echo 'objtrace:add:arg1,0x28:u32:1 if comm == "cat"' > ./events/kprobes/ \
> > - p_bio_add_page_0/trigger
> > + Secondly, we can get the value dynamically based on the object:
> >
> > - # cd /sys/kernel/debug/tracing/
> > - # echo 'p bio_add_page arg1=$arg1' > ./kprobe_events
> > - # echo 'objtrace:add:arg1,0x28:u32:1 if comm == "cat"' > ./events/kprobes/p_bio_add_page_0/trigger
> > + .. code-block::
> >
> > - # du -sh /test.txt
> > - 12.0K /test.txt
> > + find the offset of the bi_size in struct bio:
> > + $ gdb vmlinux
> > + (gdb) p &(((struct bio *)0)->bi_iter.bi_size)
> > + $1 = (unsigned int *) 0x28
> >
> > - # cat /test.txt > /dev/null
> > - # cat ./trace
> > - # tracer: nop
> > - #
> > - # entries-in-buffer/entries-written: 128/128 #P:4
> > - #
> > - # _-----=> irqs-off/BH-disabled
> > - # / _----=> need-resched
> > - # | / _---=> hardirq/softirq
> > - # || / _--=> preempt-depth
> > - # ||| / _-=> migrate-disable
> > - # |||| / delay
> > - # TASK-PID CPU# ||||| TIMESTAMP FUNCTION
> > - # | | | ||||| | |
> > - cat-117 [002] ...1. 1.602243: __bio_try_merge_page <-bio_add_page object:0xffff88811bee4000 value:0x0
> > - cat-117 [002] ...1. 1.602244: __bio_add_page <-bio_add_page object:0xffff88811bee4000 value:0x0
> > - cat-117 [002] ...2. 1.602244: bio_add_page <-ext4_mpage_readpages object:0xffff88811bee4000 value:0x1000
> > - cat-117 [002] ...1. 1.602245: __bio_try_merge_page <-bio_add_page object:0xffff88811bee4000 value:0x1000
> > - cat-117 [002] ...1. 1.602245: __bio_add_page <-bio_add_page object:0xffff88811bee4000 value:0x1000
> > - cat-117 [002] ...2. 1.602245: bio_add_page <-ext4_mpage_readpages object:0xffff88811bee4000 value:0x2000
> > - cat-117 [002] ...1. 1.602245: __bio_try_merge_page <-bio_add_page object:0xffff88811bee4000 value:0x2000
> > - cat-117 [002] ...1. 1.602245: __bio_add_page <-bio_add_page object:0xffff88811bee4000 value:0x2000
> > - cat-117 [002] ...1. 1.602245: submit_bio <-ext4_mpage_readpages object:0xffff88811bee4000 value:0x3000
> > - cat-117 [002] ...1. 1.602245: submit_bio_noacct <-ext4_mpage_readpages object:0xffff88811bee4000 value:0x3000
> > - cat-117 [002] ...1. 1.602246: __submit_bio <-submit_bio_noacct object:0xffff88811bee4000 value:0x3000
> > - cat-117 [002] ...1. 1.602246: submit_bio_checks <-__submit_bio object:0xffff88811bee4000 value:0x3000
> > - cat-117 [002] ...1. 1.602246: __cond_resched <-submit_bio_checks object:0xffff88811bee4000 value:0x3000
> > - cat-117 [002] ...1. 1.602246: should_fail_bio <-submit_bio_checks object:0xffff88811bee4000 value:0x3000
> > - cat-117 [002] ...1. 1.602246: blk_mq_submit_bio <-submit_bio_noacct object:0xffff88811bee4000 value:0x3000
> > - cat-117 [002] ...1. 1.602246: blk_attempt_plug_merge <-blk_mq_submit_bio object:0xffff88811bee4000 value:0x3000
> > - cat-117 [002] ...1. 1.602246: blk_mq_sched_bio_merge <-blk_mq_submit_bio object:0xffff88811bee4000 value:0x3000
> > - cat-117 [002] ...1. 1.602247: __rcu_read_lock <-blk_mq_submit_bio object:0xffff88811bee4000 value:0x3000
> > - cat-117 [002] ...1. 1.602247: __rcu_read_unlock <-blk_mq_submit_bio object:0xffff88811bee4000 value:0x3000
> > - cat-117 [002] ...1. 1.602247: __blk_mq_alloc_requests <-blk_mq_submit_bio object:0xffff88811bee4000 value:0x3000
> > - <idle>-0 [002] d..3. 1.602298: bio_endio <-blk_update_request object:0xffff88811bee4000 value:0x0
> > - <idle>-0 [002] d..3. 1.602298: mpage_end_io <-blk_update_request object:0xffff88811bee4000 value:0x0
> > - <idle>-0 [002] d..3. 1.602298: __read_end_io <-blk_update_request object:0xffff88811bee4000 value:0x0
> > - <idle>-0 [002] d..3. 1.602300: bio_put <-blk_update_request object:0xffff88811bee4000 value:0x0
> > - <idle>-0 [002] d..3. 1.602300: bio_free <-blk_update_request object:0xffff88811bee4000 value:0x0
> > - <idle>-0 [002] d..3. 1.602300: mempool_free <-blk_update_request object:0xffff88811bee4000 value:0x0
> > - <idle>-0 [002] d..3. 1.602300: mempool_free_slab <-blk_update_request object:0xffff88811bee4000 value:0x0
> > - <idle>-0 [002] d..3. 1.602300: kmem_cache_free <-blk_update_request object:0xffff88811bee4000 value:0x0
> > - ...
> > + # echo 'objtrace:add:arg1,0x28:u32:1 if comm == "cat"' > ./events/kprobes/ \
> > + p_bio_add_page_0/trigger
> > +
> > + # cd /sys/kernel/debug/tracing/
> > + # echo 'p bio_add_page arg1=$arg1' > ./kprobe_events
> > + # echo 'objtrace:add:arg1,0x28:u32:1 if comm == "cat"' > ./events/kprobes/p_bio_add_page_0/trigger
> > +
> > + # du -sh /test.txt
> > + 12.0K /test.txt
> > +
> > + # cat /test.txt > /dev/null
> > + # cat ./trace
> > + # tracer: nop
> > + #
> > + # entries-in-buffer/entries-written: 128/128 #P:4
> > + #
> > + # _-----=> irqs-off/BH-disabled
> > + # / _----=> need-resched
> > + # | / _---=> hardirq/softirq
> > + # || / _--=> preempt-depth
> > + # ||| / _-=> migrate-disable
> > + # |||| / delay
> > + # TASK-PID CPU# ||||| TIMESTAMP FUNCTION
> > + # | | | ||||| | |
> > + cat-117 [002] ...1. 1.602243: __bio_try_merge_page <-bio_add_page object:0xffff88811bee4000 value:0x0
> > + cat-117 [002] ...1. 1.602244: __bio_add_page <-bio_add_page object:0xffff88811bee4000 value:0x0
> > + cat-117 [002] ...2. 1.602244: bio_add_page <-ext4_mpage_readpages object:0xffff88811bee4000 value:0x1000
> > + cat-117 [002] ...1. 1.602245: __bio_try_merge_page <-bio_add_page object:0xffff88811bee4000 value:0x1000
> > + cat-117 [002] ...1. 1.602245: __bio_add_page <-bio_add_page object:0xffff88811bee4000 value:0x1000
> > + cat-117 [002] ...2. 1.602245: bio_add_page <-ext4_mpage_readpages object:0xffff88811bee4000 value:0x2000
> > + cat-117 [002] ...1. 1.602245: __bio_try_merge_page <-bio_add_page object:0xffff88811bee4000 value:0x2000
> > + cat-117 [002] ...1. 1.602245: __bio_add_page <-bio_add_page object:0xffff88811bee4000 value:0x2000
> > + cat-117 [002] ...1. 1.602245: submit_bio <-ext4_mpage_readpages object:0xffff88811bee4000 value:0x3000
> > + cat-117 [002] ...1. 1.602245: submit_bio_noacct <-ext4_mpage_readpages object:0xffff88811bee4000 value:0x3000
> > + cat-117 [002] ...1. 1.602246: __submit_bio <-submit_bio_noacct object:0xffff88811bee4000 value:0x3000
> > + cat-117 [002] ...1. 1.602246: submit_bio_checks <-__submit_bio object:0xffff88811bee4000 value:0x3000
> > + cat-117 [002] ...1. 1.602246: __cond_resched <-submit_bio_checks object:0xffff88811bee4000 value:0x3000
> > + cat-117 [002] ...1. 1.602246: should_fail_bio <-submit_bio_checks object:0xffff88811bee4000 value:0x3000
> > + cat-117 [002] ...1. 1.602246: blk_mq_submit_bio <-submit_bio_noacct object:0xffff88811bee4000 value:0x3000
> > + cat-117 [002] ...1. 1.602246: blk_attempt_plug_merge <-blk_mq_submit_bio object:0xffff88811bee4000 value:0x3000
> > + cat-117 [002] ...1. 1.602246: blk_mq_sched_bio_merge <-blk_mq_submit_bio object:0xffff88811bee4000 value:0x3000
> > + cat-117 [002] ...1. 1.602247: __rcu_read_lock <-blk_mq_submit_bio object:0xffff88811bee4000 value:0x3000
> > + cat-117 [002] ...1. 1.602247: __rcu_read_unlock <-blk_mq_submit_bio object:0xffff88811bee4000 value:0x3000
> > + cat-117 [002] ...1. 1.602247: __blk_mq_alloc_requests <-blk_mq_submit_bio object:0xffff88811bee4000 value:0x3000
> > + <idle>-0 [002] d..3. 1.602298: bio_endio <-blk_update_request object:0xffff88811bee4000 value:0x0
> > + <idle>-0 [002] d..3. 1.602298: mpage_end_io <-blk_update_request object:0xffff88811bee4000 value:0x0
> > + <idle>-0 [002] d..3. 1.602298: __read_end_io <-blk_update_request object:0xffff88811bee4000 value:0x0
> > + <idle>-0 [002] d..3. 1.602300: bio_put <-blk_update_request object:0xffff88811bee4000 value:0x0
> > + <idle>-0 [002] d..3. 1.602300: bio_free <-blk_update_request object:0xffff88811bee4000 value:0x0
> > + <idle>-0 [002] d..3. 1.602300: mempool_free <-blk_update_request object:0xffff88811bee4000 value:0x0
> > + <idle>-0 [002] d..3. 1.602300: mempool_free_slab <-blk_update_request object:0xffff88811bee4000 value:0x0
> > + <idle>-0 [002] d..3. 1.602300: kmem_cache_free <-blk_update_request object:0xffff88811bee4000 value:0x0
> > + ...
> >
> > 7. In-kernel trace event API
> > ============================
> >
> >
> > Thanks.
> >
> > --
> > An old man doll... just what I always wanted! - Clara
>
> Thanks,
> JeffXie
Thanks,
JeffXie
^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [PATCH v13 4/4] Documentation: trace/objtrace: Add documentation for objtrace
2022-06-28 1:37 ` Jeff Xie
@ 2022-06-28 2:31 ` Bagas Sanjaya
2022-06-28 2:48 ` Jeff Xie
0 siblings, 1 reply; 12+ messages in thread
From: Bagas Sanjaya @ 2022-06-28 2:31 UTC (permalink / raw)
To: Jeff Xie, Masami Hiramatsu
Cc: Steven Rostedt, mingo, Tom Zanussi, linux-kernel, linux-kselftest,
Shuah Khan, linux-doc, Jonathan Corbet, Song Chen
On 6/28/22 08:37, Jeff Xie wrote:
> Hi Masami,
>
> I would like to ask if I change the document like "Bagas Sanjaya"
> rewording in the next version.
> I don't know if I can add your Reviewed-by again, I don't know the
> rules very well ;-)
>
In the next version roll, just mention the feedback in the patch
changelog (but not in the patch message as would appear on git log).
--
An old man doll... just what I always wanted! - Clara
^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [PATCH v13 4/4] Documentation: trace/objtrace: Add documentation for objtrace
2022-06-28 2:31 ` Bagas Sanjaya
@ 2022-06-28 2:48 ` Jeff Xie
0 siblings, 0 replies; 12+ messages in thread
From: Jeff Xie @ 2022-06-28 2:48 UTC (permalink / raw)
To: Bagas Sanjaya
Cc: Masami Hiramatsu, Steven Rostedt, mingo, Tom Zanussi,
linux-kernel, linux-kselftest, Shuah Khan, linux-doc,
Jonathan Corbet, Song Chen
On Tue, Jun 28, 2022 at 10:31 AM Bagas Sanjaya <bagasdotme@gmail.com> wrote:
>
> On 6/28/22 08:37, Jeff Xie wrote:
> > Hi Masami,
> >
> > I would like to ask if I change the document like "Bagas Sanjaya"
> > rewording in the next version.
> > I don't know if I can add your Reviewed-by again, I don't know the
> > rules very well ;-)
> >
>
> In the next version roll, just mention the feedback in the patch
> changelog (but not in the patch message as would appear on git log).
Okay, thank you for your reply ;-)
> --
> An old man doll... just what I always wanted! - Clara
Thanks,
JeffXie
^ permalink raw reply [flat|nested] 12+ messages in thread