[tip:perf/probes] tracing/kprobes: Add failure messages for debugging

From: tip-bot for Masami Hiramatsu
Date: Sat Oct 17 2009 - 06:06:08 EST


Commit-ID: e63cc2397ecc0f2b604f22fb9cdbb05911c1e5d4
Gitweb: http://git.kernel.org/tip/e63cc2397ecc0f2b604f22fb9cdbb05911c1e5d4
Author: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
AuthorDate: Fri, 16 Oct 2009 20:07:28 -0400
Committer: Ingo Molnar <mingo@xxxxxxx>
CommitDate: Sat, 17 Oct 2009 09:53:58 +0200

tracing/kprobes: Add failure messages for debugging

Add verbose failure messages to kprobe-tracer for debugging.

Signed-off-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
LKML-Reference: <20091017000728.16556.16713.stgit@xxxxxxxxxxxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
---
kernel/trace/trace_kprobe.c | 35 +++++++++++++++++++++++++++--------
1 files changed, 27 insertions(+), 8 deletions(-)

diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index cdacdab..b8ef707 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -597,15 +597,19 @@ static int create_trace_probe(int argc, char **argv)
void *addr = NULL;
char buf[MAX_EVENT_NAME_LEN];

- if (argc < 2)
+ if (argc < 2) {
+ pr_info("Probe point is not specified.\n");
return -EINVAL;
+ }

if (argv[0][0] == 'p')
is_return = 0;
else if (argv[0][0] == 'r')
is_return = 1;
- else
+ else {
+ pr_info("Probe definition must be started with 'p' or 'r'.\n");
return -EINVAL;
+ }

if (argv[0][1] == ':') {
event = &argv[0][2];
@@ -625,21 +629,29 @@ static int create_trace_probe(int argc, char **argv)
}

if (isdigit(argv[1][0])) {
- if (is_return)
+ if (is_return) {
+ pr_info("Return probe point must be a symbol.\n");
return -EINVAL;
+ }
/* an address specified */
ret = strict_strtoul(&argv[0][2], 0, (unsigned long *)&addr);
- if (ret)
+ if (ret) {
+ pr_info("Failed to parse address.\n");
return ret;
+ }
} else {
/* a symbol specified */
symbol = argv[1];
/* TODO: support .init module functions */
ret = split_symbol_offset(symbol, &offset);
- if (ret)
+ if (ret) {
+ pr_info("Failed to parse symbol.\n");
return ret;
- if (offset && is_return)
+ }
+ if (offset && is_return) {
+ pr_info("Return probe must be used without offset.\n");
return -EINVAL;
+ }
}
argc -= 2; argv += 2;

@@ -658,8 +670,11 @@ static int create_trace_probe(int argc, char **argv)
}
tp = alloc_trace_probe(group, event, addr, symbol, offset, argc,
is_return);
- if (IS_ERR(tp))
+ if (IS_ERR(tp)) {
+ pr_info("Failed to allocate trace_probe.(%d)\n",
+ (int)PTR_ERR(tp));
return PTR_ERR(tp);
+ }

/* parse arguments */
ret = 0;
@@ -672,6 +687,8 @@ static int create_trace_probe(int argc, char **argv)
arg = argv[i];

if (conflict_field_name(argv[i], tp->args, i)) {
+ pr_info("Argument%d name '%s' conflicts with "
+ "another field.\n", i, argv[i]);
ret = -EINVAL;
goto error;
}
@@ -685,8 +702,10 @@ static int create_trace_probe(int argc, char **argv)
goto error;
}
ret = parse_probe_arg(arg, &tp->args[i].fetch, is_return);
- if (ret)
+ if (ret) {
+ pr_info("Parse error at argument%d. (%d)\n", i, ret);
goto error;
+ }
}
tp->nr_args = i;

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