Show the source code level information for address only kprobe
events. Currently the perf probe shows such information only
for symbol-based probes. With this change, perf-probe correctly
parses the address-based events and tries to find the actual
lines of code from the debuginfo.
E.g. without this patch;
# ./perf probe -l
probe:t_show (on 0xffffffff810d9720 with m v)
probe:t_show_1 (on 0xffffffff810e2e40 with m v t)
probe:t_show_2 (on 0xffffffff810ece30 with m v fmt)
probe:t_show_3 (on 0xffffffff810f4ad0 with m v file)
With this patch;
# ./perf probe -l
probe:t_show (on t_show@linux-3/kernel/trace/ftrace.c with m v)
probe:t_show_1 (on t_show@linux-3/kernel/trace/trace.c with m v t)
probe:t_show_2 (on t_show@kernel/trace/trace_printk.c with m v fmt)
probe:t_show_3 (on t_show@kernel/trace/trace_events.c with m v file)
Signed-off-by: Masami Hiramatsu <masami.hiramatsu...@hitachi.com>
---
tools/perf/util/probe-event.c | 87 ++++++++++++++++++++++++++---------------
1 file changed, 56 insertions(+), 31 deletions(-)
diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index 92ab688..3470934 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -153,7 +153,7 @@ static struct dso *kernel_get_module_dso(const char *module)
struct map *map;
const char *vmlinux_name;
- if (module) {
+ if (module && strcmp(module, "kernel") != 0) {
list_for_each_entry(dso, &host_machine->kernel_dsos, node) {
if (strncmp(dso->short_name + 1, module,
dso->short_name_len - 2) == 0)
@@ -220,12 +220,22 @@ out:
static int convert_to_perf_probe_point(struct probe_trace_point *tp,
struct perf_probe_point *pp)
{
- pp->function = strdup(tp->symbol);
+ char buf[128];
+ int ret;
+ if (tp->symbol) {
+ pp->function = strdup(tp->symbol);
+ pp->offset = tp->offset;
+ } else {
+ ret = e_snprintf(buf, 128, "0x%" PRIx64, (u64)tp->address);
+ if (ret < 0)
+ return ret;
+ pp->function = strdup(buf);
+ pp->offset = 0;
+ }
if (pp->function == NULL)
return -ENOMEM;
- pp->offset = tp->offset;
pp->retprobe = tp->retprobe;
return 0;
@@ -261,28 +271,35 @@ static int kprobe_convert_to_perf_probe(struct
probe_trace_point *tp,
{
struct symbol *sym;
struct map *map;
- u64 addr;
- int ret = -ENOENT;
+ u64 addr = tp->address;
+ int ret;
struct debuginfo *dinfo;
- sym = __find_kernel_function_by_name(tp->symbol, &map);
- if (sym) {
+ if (!addr) {
+ sym = __find_kernel_function_by_name(tp->symbol, &map);
+ if (!sym) {
+ ret = -ENOENT;
+ goto error;
+ }
addr = map->unmap_ip(map, sym->start + tp->offset);
- pr_debug("try to find %s+%ld@%" PRIx64 "\n", tp->symbol,
- tp->offset, addr);
+ }
+
+ pr_debug("try to find information at %" PRIx64 " in %s\n", addr,
+ tp->module ? : "kernel");
- dinfo = debuginfo__new_online_kernel(addr);
- if (dinfo) {
- ret = debuginfo__find_probe_point(dinfo,
+ dinfo = debuginfo__new_online_kernel(addr);
+ if (dinfo) {
+ ret = debuginfo__find_probe_point(dinfo,
(unsigned long)addr, pp);
- debuginfo__delete(dinfo);
- } else {
- pr_debug("Failed to open debuginfo at 0x%" PRIx64 "\n",
- addr);
- ret = -ENOENT;
- }
+ debuginfo__delete(dinfo);
+ } else {
+ pr_debug("Failed to open debuginfo at 0x%" PRIx64 "\n",
+ addr);
+ ret = -ENOENT;
}
+
if (ret <= 0) {
+error:
pr_debug("Failed to find corresponding probes from "
"debuginfo. Use kprobe event information.\n");
return convert_to_perf_probe_point(tp, pp);
@@ -745,10 +762,13 @@ static int kprobe_convert_to_perf_probe(struct
probe_trace_point *tp,
{
struct symbol *sym;
- sym = __find_kernel_function_by_name(tp->symbol, NULL);
- if (!sym) {
- pr_err("Failed to find symbol %s in kernel.\n", tp->symbol);
- return -ENOENT;
+ if (tp->symbol) {
+ sym = __find_kernel_function_by_name(tp->symbol, NULL);
+ if (!sym) {
+ pr_err("Failed to find symbol %s in kernel.\n",
+ tp->symbol);
+ return -ENOENT;
+ }
}
return convert_to_perf_probe_point(tp, pp);
@@ -1278,16 +1298,21 @@ static int parse_probe_trace_command(const char *cmd,
} else
p = argv[1];
fmt1_str = strtok_r(p, "+", &fmt);
- tp->symbol = strdup(fmt1_str);
- if (tp->symbol == NULL) {
- ret = -ENOMEM;
- goto out;
+ if (fmt1_str[0] == '0') /* only the address started with 0x */
+ tp->address = strtoul(fmt1_str, NULL, 0);
+ else {
+ /* Only the symbol-based probe has offset */
+ tp->symbol = strdup(fmt1_str);
+ if (tp->symbol == NULL) {
+ ret = -ENOMEM;
+ goto out;
+ }
+ fmt2_str = strtok_r(NULL, "", &fmt);
+ if (fmt2_str == NULL)
+ tp->offset = 0;
+ else
+ tp->offset = strtoul(fmt2_str, NULL, 10);
}
- fmt2_str = strtok_r(NULL, "", &fmt);
- if (fmt2_str == NULL)
- tp->offset = 0;
- else
- tp->offset = strtoul(fmt2_str, NULL, 10);
tev->nargs = argc - 2;
tev->args = zalloc(sizeof(struct probe_trace_arg) * tev->nargs);
--
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