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| author | Masami Hiramatsu <mhiramat@kernel.org> | 2020-09-10 10:55:35 +0200 |
|---|---|---|
| committer | Steven Rostedt (VMware) <rostedt@goodmis.org> | 2020-09-22 03:06:03 +0200 |
| commit | 4725cd89978c26405a20414f3a0fa6cbd2bf9aad (patch) | |
| tree | bd8873770bf526a373c995c145bd8b07b37043a7 | |
| parent | Documentation: tracing: Add tracing_on option to boot-time tracer (diff) | |
| download | linux-4725cd89978c26405a20414f3a0fa6cbd2bf9aad.tar.xz linux-4725cd89978c26405a20414f3a0fa6cbd2bf9aad.zip | |
tracing/kprobes: Support perf-style return probe
Support perf-style return probe ("SYMBOL%return") for kprobe events.
This will allow boot-time tracing user to define a return probe event.
Link: https://lkml.kernel.org/r/159972813535.428528.4437029657208468954.stgit@devnote2
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
| -rw-r--r-- | kernel/trace/trace.c | 2 | ||||
| -rw-r--r-- | kernel/trace/trace_kprobe.c | 18 | ||||
| -rw-r--r-- | kernel/trace/trace_probe.h | 1 |
3 files changed, 19 insertions, 2 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 55b829863127..ca6da462326d 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -5122,7 +5122,7 @@ static const char readme_msg[] = "\t -:[<group>/]<event>\n" #ifdef CONFIG_KPROBE_EVENTS "\t place: [<module>:]<symbol>[+<offset>]|<memaddr>\n" - "place (kretprobe): [<module>:]<symbol>[+<offset>]|<memaddr>\n" + "place (kretprobe): [<module>:]<symbol>[+<offset>]%return|<memaddr>\n" #endif #ifdef CONFIG_UPROBE_EVENTS " place (uprobe): <path>:<offset>[(ref_ctr_offset)]\n" diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c index f8e46929ceba..9d46415296eb 100644 --- a/kernel/trace/trace_kprobe.c +++ b/kernel/trace/trace_kprobe.c @@ -718,6 +718,9 @@ static int trace_kprobe_create(int argc, const char *argv[]) * p[:[GRP/]EVENT] [MOD:]KSYM[+OFFS]|KADDR [FETCHARGS] * - Add kretprobe: * r[MAXACTIVE][:[GRP/]EVENT] [MOD:]KSYM[+0] [FETCHARGS] + * Or + * p:[GRP/]EVENT] [MOD:]KSYM[+0]%return [FETCHARGS] + * * Fetch args: * $retval : fetch return value * $stack : fetch stack address @@ -747,7 +750,6 @@ static int trace_kprobe_create(int argc, const char *argv[]) switch (argv[0][0]) { case 'r': is_return = true; - flags |= TPARG_FL_RETURN; break; case 'p': break; @@ -805,12 +807,26 @@ static int trace_kprobe_create(int argc, const char *argv[]) symbol = kstrdup(argv[1], GFP_KERNEL); if (!symbol) return -ENOMEM; + + tmp = strchr(symbol, '%'); + if (tmp) { + if (!strcmp(tmp, "%return")) { + *tmp = '\0'; + is_return = true; + } else { + trace_probe_log_err(tmp - symbol, BAD_ADDR_SUFFIX); + goto parse_error; + } + } + /* TODO: support .init module functions */ ret = traceprobe_split_symbol_offset(symbol, &offset); if (ret || offset < 0 || offset > UINT_MAX) { trace_probe_log_err(0, BAD_PROBE_ADDR); goto parse_error; } + if (is_return) + flags |= TPARG_FL_RETURN; if (kprobe_on_func_entry(NULL, symbol, offset)) flags |= TPARG_FL_FENTRY; if (offset && is_return && !(flags & TPARG_FL_FENTRY)) { diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h index a22b62813f8c..04d00987da69 100644 --- a/kernel/trace/trace_probe.h +++ b/kernel/trace/trace_probe.h @@ -404,6 +404,7 @@ extern int traceprobe_define_arg_fields(struct trace_event_call *event_call, C(MAXACT_TOO_BIG, "Maxactive is too big"), \ C(BAD_PROBE_ADDR, "Invalid probed address or symbol"), \ C(BAD_RETPROBE, "Retprobe address must be an function entry"), \ + C(BAD_ADDR_SUFFIX, "Invalid probed address suffix"), \ C(NO_GROUP_NAME, "Group name is not specified"), \ C(GROUP_TOO_LONG, "Group name is too long"), \ C(BAD_GROUP_NAME, "Group name must follow the same rules as C identifiers"), \ |