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Message-ID: <20220524183159.21bac428@gandalf.local.home>
Date: Tue, 24 May 2022 18:31:59 -0400
From: Steven Rostedt <rostedt@...dmis.org>
To: Linyu Yuan <quic_linyyuan@...cinc.com>
Cc: Ingo Molnar <mingo@...hat.com>, <linux-kernel@...r.kernel.org>,
Masami Hiramatsu <mhiramat@...nel.org>,
Tom Zanussi <zanussi@...nel.org>
Subject: Re: [PATCH 1/2] tracing/probes: auto generate events name when
create a group of events
[ Adding Masami (kprobe maintainer) and Tom (dynamic event maintainer) ]
On Sun, 1 May 2022 17:34:10 +0800
Linyu Yuan <quic_linyyuan@...cinc.com> wrote:
> change traceprobe_parse_event_name() and return GRP/EVENT types,
> TP_ENAME_GROUP_EVENT means user input GRP/EVENT format,
> TP_ENAME_EVENT means user only input EVENT format,
> TP_ENAME_GROUP means user only input GRP/ format,
>
> it allow no event name input when create a group of events,
> and will auto generate event name according second argument.
Sorry, but I can't understand the above. Can you reword it, and perhaps
include an example of what this patch does.
After reading the code, I guess you are trying to make it so that you can
leave out the event name and only have the group name, if you add the slash.
echo 'p:group/ schedule' > kprobe_events
And that will create a kprobe "schedule" event under the "group" system?
Also, for some reason, patch 2 of the series never came to me. But it is in
my LKML folder :-/
>
> Signed-off-by: Linyu Yuan <quic_linyyuan@...cinc.com>
> ---
> Documentation/trace/kprobetrace.rst | 8 ++++----
> Documentation/trace/uprobetracer.rst | 8 ++++----
> kernel/trace/trace_dynevent.c | 2 +-
> kernel/trace/trace_eprobe.c | 19 +++++++++++--------
> kernel/trace/trace_kprobe.c | 18 +++++++++++-------
> kernel/trace/trace_probe.c | 9 ++++++++-
> kernel/trace/trace_probe.h | 4 ++++
> kernel/trace/trace_uprobe.c | 14 +++++++++-----
> 8 files changed, 52 insertions(+), 30 deletions(-)
>
> diff --git a/Documentation/trace/kprobetrace.rst b/Documentation/trace/kprobetrace.rst
> index b175d88..4274cc6 100644
> --- a/Documentation/trace/kprobetrace.rst
> +++ b/Documentation/trace/kprobetrace.rst
> @@ -28,10 +28,10 @@ Synopsis of kprobe_events
> -------------------------
> ::
>
> - p[:[GRP/]EVENT] [MOD:]SYM[+offs]|MEMADDR [FETCHARGS] : Set a probe
> - r[MAXACTIVE][:[GRP/]EVENT] [MOD:]SYM[+0] [FETCHARGS] : Set a return probe
> - p:[GRP/]EVENT] [MOD:]SYM[+0]%return [FETCHARGS] : Set a return probe
> - -:[GRP/]EVENT : Clear a probe
> + p[:[GRP/][EVENT]] [MOD:]SYM[+offs]|MEMADDR [FETCHARGS] : Set a probe
> + r[MAXACTIVE][:[GRP/][EVENT]] [MOD:]SYM[+0] [FETCHARGS] : Set a return probe
> + p[:[GRP/][EVENT]] [MOD:]SYM[+0]%return [FETCHARGS] : Set a return probe
> + -:[GRP/][EVENT] : Clear a probe
>
> GRP : Group name. If omitted, use "kprobes" for it.
> EVENT : Event name. If omitted, the event name is generated
> diff --git a/Documentation/trace/uprobetracer.rst b/Documentation/trace/uprobetracer.rst
> index a8e5938..3a1797d7 100644
> --- a/Documentation/trace/uprobetracer.rst
> +++ b/Documentation/trace/uprobetracer.rst
> @@ -26,10 +26,10 @@ Synopsis of uprobe_tracer
> -------------------------
> ::
>
> - p[:[GRP/]EVENT] PATH:OFFSET [FETCHARGS] : Set a uprobe
> - r[:[GRP/]EVENT] PATH:OFFSET [FETCHARGS] : Set a return uprobe (uretprobe)
> - p[:[GRP/]EVENT] PATH:OFFSET%return [FETCHARGS] : Set a return uprobe (uretprobe)
> - -:[GRP/]EVENT : Clear uprobe or uretprobe event
> + p[:[GRP/][EVENT]] PATH:OFFSET [FETCHARGS] : Set a uprobe
> + r[:[GRP/][EVENT]] PATH:OFFSET [FETCHARGS] : Set a return uprobe (uretprobe)
> + p[:[GRP/][EVENT]] PATH:OFFSET%return [FETCHARGS] : Set a return uprobe (uretprobe)
> + -:[GRP/][EVENT] : Clear uprobe or uretprobe event
>
> GRP : Group name. If omitted, "uprobes" is the default value.
> EVENT : Event name. If omitted, the event name is generated based
> diff --git a/kernel/trace/trace_dynevent.c b/kernel/trace/trace_dynevent.c
> index e34e8182..033248d 100644
> --- a/kernel/trace/trace_dynevent.c
> +++ b/kernel/trace/trace_dynevent.c
> @@ -101,7 +101,7 @@ int dyn_event_release(const char *raw_command, struct dyn_event_operations *type
> event = p + 1;
> *p = '\0';
> }
> - if (event[0] == '\0') {
> + if (!system && event[0] == '\0') {
> ret = -EINVAL;
> goto out;
> }
> diff --git a/kernel/trace/trace_eprobe.c b/kernel/trace/trace_eprobe.c
> index 7d44785..b16e067 100644
> --- a/kernel/trace/trace_eprobe.c
> +++ b/kernel/trace/trace_eprobe.c
> @@ -125,6 +125,7 @@ static bool eprobe_dyn_event_match(const char *system, const char *event,
> * We match the following:
> * event only - match all eprobes with event name
> * system and event only - match all system/event probes
> + * system only - match all system probes
> *
> * The below has the above satisfied with more arguments:
> *
> @@ -143,7 +144,7 @@ static bool eprobe_dyn_event_match(const char *system, const char *event,
> return false;
>
> /* Must match the event name */
> - if (strcmp(trace_probe_name(&ep->tp), event) != 0)
> + if (event[0] != '\0' && strcmp(trace_probe_name(&ep->tp), event) != 0)
> return false;
>
> /* No arguments match all */
> @@ -848,7 +849,7 @@ static int __trace_eprobe_create(int argc, const char *argv[])
> {
> /*
> * Argument syntax:
> - * e[:[GRP/]ENAME] SYSTEM.EVENT [FETCHARGS]
> + * e[:[GRP/][ENAME]] SYSTEM.EVENT [FETCHARGS]
> * Fetch args:
> * <name>=$<field>[:TYPE]
> */
> @@ -858,6 +859,7 @@ static int __trace_eprobe_create(int argc, const char *argv[])
> struct trace_eprobe *ep = NULL;
> char buf1[MAX_EVENT_NAME_LEN];
> char buf2[MAX_EVENT_NAME_LEN];
> + char grp_buf[MAX_EVENT_NAME_LEN];
> int ret = 0;
> int i;
>
> @@ -866,14 +868,16 @@ static int __trace_eprobe_create(int argc, const char *argv[])
>
> trace_probe_log_init("event_probe", argc, argv);
>
> + ret = TP_ENAME_EMPTTY;
EMPTY is spelled wrong.
> event = strchr(&argv[0][1], ':');
> if (event) {
> event++;
> - ret = traceprobe_parse_event_name(&event, &group, buf1,
> + ret = traceprobe_parse_event_name(&event, &group, grp_buf,
> event - argv[0]);
> - if (ret)
> + if (ret < 0)
> goto parse_error;
> - } else {
> + }
add space.
> + if (ret == TP_ENAME_EMPTTY || ret == TP_ENAME_GROUP) {
> strscpy(buf1, argv[1], MAX_EVENT_NAME_LEN);
> sanitize_event_name(buf1);
> event = buf1;
I'd like to see Masami's and Tom's comments on this one.
-- Steve
> @@ -882,9 +886,8 @@ static int __trace_eprobe_create(int argc, const char *argv[])
> goto parse_error;
>
> sys_event = argv[1];
> - ret = traceprobe_parse_event_name(&sys_event, &sys_name, buf2,
> - sys_event - argv[1]);
> - if (ret || !sys_name)
> + ret = traceprobe_parse_event_name(&sys_event, &sys_name, buf2, 0);
> + if (ret != TP_ENAME_GROUP_EVENT)
> goto parse_error;
> if (!is_good_name(sys_event) || !is_good_name(sys_name))
> goto parse_error;
> diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
> index 47cebef..2cd8ef9 100644
> --- a/kernel/trace/trace_kprobe.c
> +++ b/kernel/trace/trace_kprobe.c
> @@ -163,7 +163,8 @@ static bool trace_kprobe_match(const char *system, const char *event,
> {
> struct trace_kprobe *tk = to_trace_kprobe(ev);
>
> - return strcmp(trace_probe_name(&tk->tp), event) == 0 &&
> + return (event[0] == '\0' ||
> + strcmp(trace_probe_name(&tk->tp), event) == 0) &&
> (!system || strcmp(trace_probe_group_name(&tk->tp), system) == 0) &&
> trace_kprobe_match_command_head(tk, argc, argv);
> }
> @@ -708,11 +709,11 @@ static int __trace_kprobe_create(int argc, const char *argv[])
> /*
> * Argument syntax:
> * - Add kprobe:
> - * p[:[GRP/]EVENT] [MOD:]KSYM[+OFFS]|KADDR [FETCHARGS]
> + * p[:[GRP/][EVENT]] [MOD:]KSYM[+OFFS]|KADDR [FETCHARGS]
> * - Add kretprobe:
> - * r[MAXACTIVE][:[GRP/]EVENT] [MOD:]KSYM[+0] [FETCHARGS]
> + * r[MAXACTIVE][:[GRP/][EVENT]] [MOD:]KSYM[+0] [FETCHARGS]
> * Or
> - * p:[GRP/]EVENT] [MOD:]KSYM[+0]%return [FETCHARGS]
> + * p[:[GRP/][EVENT]] [MOD:]KSYM[+0]%return [FETCHARGS]
> *
> * Fetch args:
> * $retval : fetch return value
> @@ -739,6 +740,7 @@ static int __trace_kprobe_create(int argc, const char *argv[])
> long offset = 0;
> void *addr = NULL;
> char buf[MAX_EVENT_NAME_LEN];
> + char grp_buf[MAX_EVENT_NAME_LEN];
> unsigned int flags = TPARG_FL_KERNEL;
>
> switch (argv[0][0]) {
> @@ -832,12 +834,14 @@ static int __trace_kprobe_create(int argc, const char *argv[])
> }
>
> trace_probe_log_set_index(0);
> + ret = TP_ENAME_EMPTTY;
> if (event) {
> - ret = traceprobe_parse_event_name(&event, &group, buf,
> + ret = traceprobe_parse_event_name(&event, &group, grp_buf,
> event - argv[0]);
> - if (ret)
> + if (ret < 0)
> goto parse_error;
> - } else {
> + }
> + if (ret == TP_ENAME_EMPTTY || ret == TP_ENAME_GROUP) {
> /* Make a new event name */
> if (symbol)
> snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_%ld",
> diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c
> index 80863c6..7fd50ab 100644
> --- a/kernel/trace/trace_probe.c
> +++ b/kernel/trace/trace_probe.c
> @@ -257,6 +257,9 @@ int traceprobe_parse_event_name(const char **pevent, const char **pgroup,
> }
> len = strlen(event);
> if (len == 0) {
> + if (slash)
> + return TP_ENAME_GROUP;
> +
> trace_probe_log_err(offset, NO_EVENT_NAME);
> return -EINVAL;
> } else if (len > MAX_EVENT_NAME_LEN) {
> @@ -267,7 +270,11 @@ int traceprobe_parse_event_name(const char **pevent, const char **pgroup,
> trace_probe_log_err(offset, BAD_EVENT_NAME);
> return -EINVAL;
> }
> - return 0;
> +
> + if (slash)
> + return TP_ENAME_GROUP_EVENT;
> +
> + return TP_ENAME_EVENT;
> }
>
> #define PARAM_MAX_STACK (THREAD_SIZE / sizeof(unsigned long))
> diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h
> index 92cc149..d726769 100644
> --- a/kernel/trace/trace_probe.h
> +++ b/kernel/trace/trace_probe.h
> @@ -364,6 +364,10 @@ extern void traceprobe_free_probe_arg(struct probe_arg *arg);
> extern int traceprobe_split_symbol_offset(char *symbol, long *offset);
> int traceprobe_parse_event_name(const char **pevent, const char **pgroup,
> char *buf, int offset);
> +#define TP_ENAME_GROUP_EVENT 0
> +#define TP_ENAME_EVENT 1
> +#define TP_ENAME_GROUP 2
> +#define TP_ENAME_EMPTTY 3
>
> enum probe_print_type {
> PROBE_PRINT_NORMAL,
> diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
> index 9711589..a935c08 100644
> --- a/kernel/trace/trace_uprobe.c
> +++ b/kernel/trace/trace_uprobe.c
> @@ -312,7 +312,8 @@ static bool trace_uprobe_match(const char *system, const char *event,
> {
> struct trace_uprobe *tu = to_trace_uprobe(ev);
>
> - return strcmp(trace_probe_name(&tu->tp), event) == 0 &&
> + return (event[0] == '\0' ||
> + strcmp(trace_probe_name(&tu->tp), event) == 0) &&
> (!system || strcmp(trace_probe_group_name(&tu->tp), system) == 0) &&
> trace_uprobe_match_command_head(tu, argc, argv);
> }
> @@ -532,7 +533,7 @@ static int register_trace_uprobe(struct trace_uprobe *tu)
>
> /*
> * Argument syntax:
> - * - Add uprobe: p|r[:[GRP/]EVENT] PATH:OFFSET[%return][(REF)] [FETCHARGS]
> + * - Add uprobe: p|r[:[GRP/][EVENT]] PATH:OFFSET[%return][(REF)] [FETCHARGS]
> */
> static int __trace_uprobe_create(int argc, const char **argv)
> {
> @@ -540,6 +541,7 @@ static int __trace_uprobe_create(int argc, const char **argv)
> const char *event = NULL, *group = UPROBE_EVENT_SYSTEM;
> char *arg, *filename, *rctr, *rctr_end, *tmp;
> char buf[MAX_EVENT_NAME_LEN];
> + char grp_buf[MAX_EVENT_NAME_LEN];
> enum probe_print_type ptype;
> struct path path;
> unsigned long offset, ref_ctr_offset;
> @@ -644,12 +646,14 @@ static int __trace_uprobe_create(int argc, const char **argv)
>
> /* setup a probe */
> trace_probe_log_set_index(0);
> + ret = TP_ENAME_EMPTTY;
> if (event) {
> - ret = traceprobe_parse_event_name(&event, &group, buf,
> + ret = traceprobe_parse_event_name(&event, &group, grp_buf,
> event - argv[0]);
> - if (ret)
> + if (ret < 0)
> goto fail_address_parse;
> - } else {
> + }
> + if (ret == TP_ENAME_EMPTTY || ret == TP_ENAME_GROUP) {
> char *tail;
> char *ptr;
>
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