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    Subject[RFC][PATCH v5 2/4] trace/objtrace: get the value of the object
    Date
    Signed-off-by: Jeff Xie <xiehuan09@gmail.com>
    ---
    kernel/trace/trace_entries.h | 5 +-
    kernel/trace/trace_object.c | 121 +++++++++++++++++++++++++++++------
    kernel/trace/trace_output.c | 6 +-
    3 files changed, 107 insertions(+), 25 deletions(-)

    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 69465c2ffb7e..14993f7d0e5a 100644
    --- a/kernel/trace/trace_object.c
    +++ b/kernel/trace/trace_object.c
    @@ -11,14 +11,25 @@

    static DEFINE_PER_CPU(atomic_t, trace_object_event_disable);
    static struct trace_event_file event_trace_file;
    -static const int max_args_num = 6;
    static const int max_obj_pool = 10;
    static atomic_t trace_object_ref;
    static int exit_trace_object(void);
    static int init_trace_object(void);

    +struct objtrace_trigger_data {
    + struct ftrace_event_field *field;
    + long offset;
    + int type_size;
    +};
    +
    +struct objtrace_fetch_type {
    + char *name;
    + int type_size;
    +};
    +
    struct object_instance {
    void *object;
    + int obj_type_size;
    struct freelist_node freelist;
    };

    @@ -59,8 +70,7 @@ static bool object_empty(void)
    return ret;
    }

    -
    -static void set_trace_object(void *obj)
    +static void set_trace_object(void *obj, int type_size)
    {
    struct freelist_node *fn;
    struct object_instance *ins;
    @@ -79,6 +89,7 @@ static void set_trace_object(void *obj)

    ins = container_of(fn, struct object_instance, freelist);
    ins->object = obj;
    + ins->obj_type_size = type_size;

    freelist_add(&ins->freelist, &obj_pool->customer_freelist);
    atomic_inc(&obj_pool->nobject);
    @@ -135,7 +146,7 @@ static int init_object_pool(void)
    }

    static void submit_trace_object(unsigned long ip, unsigned long parent_ip,
    - unsigned long object)
    + unsigned long object, unsigned long value)
    {

    struct trace_buffer *buffer;
    @@ -152,6 +163,7 @@ 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;

    event_trigger_unlock_commit(&event_trace_file, buffer, event,
    entry, pc);
    @@ -161,10 +173,11 @@ 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);
    - unsigned long obj;
    + struct freelist_node *node;
    + struct object_instance *inst;
    + unsigned long val = 0;
    long disabled;
    - int cpu, n;
    + int cpu;

    preempt_disable_notrace();

    @@ -177,10 +190,14 @@ trace_object_events_call(unsigned long ip, unsigned long parent_ip,
    if (object_empty())
    goto out;

    - for (n = 0; n < max_args_num; n++) {
    - obj = regs_get_kernel_argument(pt_regs, n);
    - if (object_exist((void *)obj))
    - submit_trace_object(ip, parent_ip, obj);
    + node = obj_pool->customer_freelist.head;
    +
    + while (node) {
    + inst = container_of(node, struct object_instance, freelist);
    + if (copy_from_kernel_nofault(&val, inst->object, inst->obj_type_size))
    + goto out;
    + submit_trace_object(ip, parent_ip, (unsigned long)inst->object, val);
    + node = node->next;
    }

    out:
    @@ -198,12 +215,14 @@ 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 ftrace_event_field *field;
    + void *obj, *val = NULL;

    - struct ftrace_event_field *field = data->private_data;
    - void *obj = NULL;
    -
    - memcpy(&obj, rec + field->offset, sizeof(obj));
    - set_trace_object(obj);
    + field = obj_data->field;
    + memcpy(&val, rec + field->offset, sizeof(val));
    + obj = val + obj_data->offset;
    + set_trace_object(obj, obj_data->type_size);
    }

    static void
    @@ -350,6 +369,22 @@ static void unregister_object_trigger(char *glob, struct event_trigger_ops *ops,
    }
    }

    +static const struct objtrace_fetch_type objtrace_fetch_types[] = {
    + {"u8", 1},
    + {"s8", 1},
    + {"x8", 1},
    + {"u16", 2},
    + {"s16", 2},
    + {"x16", 2},
    + {"u32", 4},
    + {"s32", 4},
    + {"x32", 4},
    + {"u64", 8},
    + {"s64", 8},
    + {"x64", 8},
    + {}
    +};
    +
    static int
    event_object_trigger_callback(struct event_command *cmd_ops,
    struct trace_event_file *file,
    @@ -357,13 +392,15 @@ event_object_trigger_callback(struct event_command *cmd_ops,
    {
    struct event_trigger_data *trigger_data;
    struct event_trigger_ops *trigger_ops;
    + struct objtrace_trigger_data *obj_data;
    struct trace_event_call *call;
    struct ftrace_event_field *field;
    char *objtrace_cmd;
    + long offset = 0;
    char *trigger = NULL;
    - char *arg;
    + char *arg, *type, *tr, *tr_end;
    char *number;
    - int ret;
    + int ret, i, type_size = 0;

    ret = -EINVAL;
    if (!param)
    @@ -386,6 +423,38 @@ event_object_trigger_callback(struct event_command *cmd_ops,
    arg = strsep(&trigger, ":");
    if (!arg)
    goto out;
    +
    + tr = strchr(arg, '(');
    + /* now force to get the value of the val. */
    + if (!tr)
    + goto out;
    + tr_end = strchr(tr, ')');
    + if (!tr_end)
    + goto out;
    + *tr++ = '\0';
    + *tr_end = '\0';
    + ret = kstrtol(arg, 0, &offset);
    + if (ret)
    + goto out;
    + arg = tr;
    + ret = -EINVAL;
    + if (!trigger)
    + goto out;
    +
    + type = strsep(&trigger, ":");
    + if (!type)
    + goto out;
    + for (i = 0; objtrace_fetch_types[i].name; i++) {
    + if (strcmp(objtrace_fetch_types[i].name, type) == 0) {
    + type_size = objtrace_fetch_types[i].type_size;
    + break;
    + }
    + }
    +
    + if (type_size == 0)
    + goto out;
    +
    +
    call = file->event_call;
    field = trace_find_event_field(call, arg);
    if (!field)
    @@ -394,19 +463,30 @@ event_object_trigger_callback(struct event_command *cmd_ops,
    trigger_ops = cmd_ops->get_trigger_ops(cmd, trigger);

    ret = -ENOMEM;
    + obj_data = kzalloc(sizeof(*obj_data), GFP_KERNEL);
    + if (!obj_data)
    + goto out;
    +
    + obj_data->field = field;
    + obj_data->offset = offset;
    + obj_data->type_size = type_size;
    +
    trigger_data = kzalloc(sizeof(*trigger_data), GFP_KERNEL);
    - if (!trigger_data)
    + if (!trigger_data) {
    + kfree(obj_data);
    goto out;
    + }

    trigger_data->count = -1;
    trigger_data->ops = trigger_ops;
    trigger_data->cmd_ops = cmd_ops;
    - trigger_data->private_data = field;
    + trigger_data->private_data = obj_data;
    INIT_LIST_HEAD(&trigger_data->list);
    INIT_LIST_HEAD(&trigger_data->named_list);

    if (glob[0] == '!') {
    cmd_ops->unreg(glob+1, trigger_ops, trigger_data, file);
    + kfree(obj_data);
    kfree(trigger_data);
    ret = 0;
    goto out;
    @@ -461,6 +541,7 @@ event_object_trigger_callback(struct event_command *cmd_ops,
    out_free:
    if (cmd_ops->set_filter)
    cmd_ops->set_filter(NULL, trigger_data, NULL);
    + kfree(obj_data);
    kfree(trigger_data);
    goto out;
    }
    diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c
    index 76ca560af693..c8c427c23127 100644
    --- a/kernel/trace/trace_output.c
    +++ b/kernel/trace/trace_output.c
    @@ -1562,6 +1562,7 @@ 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);
    @@ -1574,9 +1575,8 @@ 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
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      Last update: 2021-11-13 13:08    [W:2.979 / U:0.088 seconds]
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