Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 93FD4C433F5 for ; Fri, 26 Nov 2021 15:28:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1354715AbhKZPb6 (ORCPT ); Fri, 26 Nov 2021 10:31:58 -0500 Received: from sin.source.kernel.org ([145.40.73.55]:40460 "EHLO sin.source.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1354576AbhKZP3z (ORCPT ); Fri, 26 Nov 2021 10:29:55 -0500 X-Greylist: delayed 445 seconds by postgrey-1.27 at vger.kernel.org; Fri, 26 Nov 2021 10:29:55 EST Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by sin.source.kernel.org (Postfix) with ESMTPS id 94AF6CE2075 for ; Fri, 26 Nov 2021 15:19:11 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4D520C93056; Fri, 26 Nov 2021 15:19:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1637939949; bh=zMRexxUDXrXbkyqqQl4Ki21LvRd8du2CKM0f0HdaByc=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=tRMMI7fUuOZEmvseSQbKclEi9BWX0emLKJmcC5a/qXq2YYhyjn2mqV8VeFa7GZG7T LMZ7T8zqB0d1GZpCE5JBAE7V6KyW+ywEKadGa3ElHLjI3mp/wz8c+ANUQnGvlZpOOE j1RcK3XUX+8q0HdbtisKgeYpF1bTv+xZf/fZrGqvMEhdzbP5w1QVAVOfKmhbDXBugz eq4D9GYhP180zhR7VThcEIQL5fSmb6NaovEk9V9xMFr4/fuamULwD3v2u608E91Vrf coTr23dm1O8JYZe6HIDPTLS/nOh1eeFjMO6DCf2MIzNyu+C1/tog0fVICe6/h+KtzJ V+AVW27mXOKmA== Date: Sat, 27 Nov 2021 00:19:05 +0900 From: Masami Hiramatsu To: Jeff Xie Cc: Steven Rostedt , mingo@redhat.com, Tom Zanussi , linux-kernel@vger.kernel.org Subject: Re: [RFC][PATCH v5 2/4] trace/objtrace: get the value of the object Message-Id: <20211127001905.22f521e44f4e89c78dc03e8c@kernel.org> In-Reply-To: References: <20211113120632.94754-1-xiehuan09@gmail.com> <20211113120632.94754-2-xiehuan09@gmail.com> <20211119230118.2f8689d630817cb103161402@kernel.org> X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.32; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello Jeff, On Fri, 26 Nov 2021 21:47:24 +0800 Jeff Xie wrote: > Hi Masami, > > On Mon, Nov 22, 2021 at 1:15 AM Jeff Xie wrote: > > > > Hi Masami, > > > > On Fri, Nov 19, 2021 at 10:01 PM Masami Hiramatsu wrote: > > > > > > Hi Jeff, > > > > > > On Sat, 13 Nov 2021 20:06:30 +0800 > > > Jeff Xie wrote: > > > > > > Please describe here what feature this patch adds. > > > How to use, and new syntax, etc. > > > > > > BTW, the syntax for this value trace is a bit confusing. > > > > > > objtrace:add:OFFS(OBJ):TYPE[:COUNT] > > > > > > This trace "OBJ", but from the user point of view, this seems to trace > > > "OFFS(OBJ)". > > > > > > I rather like make it optional and split from OBJ as below; > > > > > > objtrace:add:OBJ[,OFFS:TYPE][:COUNT] > > I have been thinking about this place for a long time, would it be > better if it like below? > objtrace:add:OBJ[,OFFS][:TYPE][:COUNT] > > If the user does not specify the type, the default type will be u64. u64 or ulong? In kprobe event, I chose ulong (u32 for 32bit arch and u64 for 64bit arch). If the object or the data at offs is a pointer, it is better to use appropriate type for each arch. Thank you, > > > > > > > (Note that the part braced by [] is optional.) > > > > Thank you for your suggestion, it does seem clearer, I will modify it like this. > > > > > Thank you, > > > > > > > Signed-off-by: Jeff Xie > > > > --- > > > > 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 > > > > > > > > > > > > > -- > > > Masami Hiramatsu > > > > Thanks, > > --- > > JeffXie > > --- > JeffXie -- Masami Hiramatsu