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tracing/kprobes: Support custom subsystem for each kprobe event

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Support specifying a custom subsystem(group) for each kprobe event.
This allows users to create new group to control several probes
at once, or add events to existing groups as additional tracepoints.

New synopsis:
 p[:[subsys/]event-name] KADDR|KSYM[+offs] [ARGS]

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Jim Keniston <jkenisto@us.ibm.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Frank Ch. Eigler <fche@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Jason Baron <jbaron@redhat.com>
Cc: K.Prasad <prasad@linux.vnet.ibm.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tom Zanussi <tzanussi@gmail.com>
LKML-Reference: <20090910235353.22412.15149.stgit@dhcp-100-2-132.bos.redhat.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
This commit is contained in:
Masami Hiramatsu 2009-09-10 19:53:53 -04:00 committed by Frederic Weisbecker
parent 6e9f23d161
commit f52487e9c0
2 changed files with 30 additions and 8 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

5
Documentation/trace/kprobetrace.txt
View file

@ -25,9 +25,10 @@ probe events via /sys/kernel/debug/tracing/events/kprobes/<EVENT>/filter.
Synopsis of kprobe_events
-------------------------
p[:EVENT] SYMBOL[+offs]|MEMADDR [FETCHARGS] : Set a probe
r[:EVENT] SYMBOL[+0] [FETCHARGS] : Set a return probe
p[:[GRP/]EVENT] SYMBOL[+offs]|MEMADDR [FETCHARGS] : Set a probe
r[:[GRP/]EVENT] SYMBOL[+0] [FETCHARGS] : Set a return probe
GRP : Group name. If omitted, use "kprobes" for it.
EVENT : Event name. If omitted, the event name is generated
based on SYMBOL+offs or MEMADDR.
SYMBOL[+offs] : Symbol+offset where the probe is inserted.

33
kernel/trace/trace_kprobe.c
View file

@ -36,6 +36,7 @@
#define MAX_TRACE_ARGS 128
#define MAX_ARGSTR_LEN 63
#define MAX_EVENT_NAME_LEN 64
#define KPROBE_EVENT_SYSTEM "kprobes"
/* currently, trace_kprobe only supports X86. */
@ -265,7 +266,8 @@ static LIST_HEAD(probe_list);
/*
* Allocate new trace_probe and initialize it (including kprobes).
*/
static struct trace_probe *alloc_trace_probe(const char *event,
static struct trace_probe *alloc_trace_probe(const char *group,
const char *event,
void *addr,
const char *symbol,
unsigned long offs,
@ -298,9 +300,16 @@ static struct trace_probe *alloc_trace_probe(const char *event,
if (!tp->call.name)
goto error;
if (!group)
goto error;
tp->call.system = kstrdup(group, GFP_KERNEL);
if (!tp->call.system)
goto error;
INIT_LIST_HEAD(&tp->list);
return tp;
error:
kfree(tp->call.name);
kfree(tp->symbol);
kfree(tp);
return ERR_PTR(-ENOMEM);
@ -322,6 +331,7 @@ static void free_trace_probe(struct trace_probe *tp)
for (i = 0; i < tp->nr_args; i++)
free_probe_arg(&tp->args[i]);
kfree(tp->call.system);
kfree(tp->call.name);
kfree(tp->symbol);
kfree(tp);
@ -530,8 +540,8 @@ static int create_trace_probe(int argc, char **argv)
{
/*
* Argument syntax:
* - Add kprobe: p[:EVENT] SYMBOL[+OFFS]|ADDRESS [FETCHARGS]
* - Add kretprobe: r[:EVENT] SYMBOL[+0] [FETCHARGS]
* - Add kprobe: p[:[GRP/]EVENT] KSYM[+OFFS]|KADDR [FETCHARGS]
* - Add kretprobe: r[:[GRP/]EVENT] KSYM[+0] [FETCHARGS]
* Fetch args:
* aN : fetch Nth of function argument. (N:0-)
* rv : fetch return value
@ -549,7 +559,7 @@ static int create_trace_probe(int argc, char **argv)
struct trace_probe *tp;
int i, ret = 0;
int is_return = 0;
char *symbol = NULL, *event = NULL, *arg = NULL;
char *symbol = NULL, *event = NULL, *arg = NULL, *group = NULL;
unsigned long offset = 0;
void *addr = NULL;
char buf[MAX_EVENT_NAME_LEN];
@ -566,6 +576,15 @@ static int create_trace_probe(int argc, char **argv)
if (argv[0][1] == ':') {
event = &argv[0][2];
if (strchr(event, '/')) {
group = event;
event = strchr(group, '/') + 1;
event[-1] = '\0';
if (strlen(group) == 0) {
pr_info("Group name is not specifiled\n");
return -EINVAL;
}
}
if (strlen(event) == 0) {
pr_info("Event name is not specifiled\n");
return -EINVAL;
@ -592,6 +611,8 @@ static int create_trace_probe(int argc, char **argv)
argc -= 2; argv += 2;
/* setup a probe */
if (!group)
group = KPROBE_EVENT_SYSTEM;
if (!event) {
/* Make a new event name */
if (symbol)
@ -602,7 +623,8 @@ static int create_trace_probe(int argc, char **argv)
is_return ? 'r' : 'p', addr);
event = buf;
}
tp = alloc_trace_probe(event, addr, symbol, offset, argc, is_return);
tp = alloc_trace_probe(group, event, addr, symbol, offset, argc,
is_return);
if (IS_ERR(tp))
return PTR_ERR(tp);
@ -1217,7 +1239,6 @@ static int register_probe_event(struct trace_probe *tp)
int ret;
/* Initialize ftrace_event_call */
call->system = "kprobes";
if (probe_is_return(tp)) {
tp->event.trace = print_kretprobe_event;
call->raw_init = probe_event_raw_init;