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| author |   Masami Hiramatsu <mhiramat@kernel.org> | 2020-09-10 17:55:35 +0900 |
|---|---|---|
| committer |   Steven Rostedt (VMware) <rostedt@goodmis.org> | 2020-09-21 21:06:03 -0400 |
| commit | 4725cd89978c26405a20414f3a0fa6cbd2bf9aad (patch) | |
| tree | bd8873770bf526a373c995c145bd8b07b37043a7 /kernel/trace/trace_kprobe.c | |
| parent | Documentation: tracing: Add tracing_on option to boot-time tracer (diff) | |
| download | linux-dev-4725cd89978c26405a20414f3a0fa6cbd2bf9aad.tar.xz linux-dev-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>
Diffstat (limited to 'kernel/trace/trace_kprobe.c')
| -rw-r--r-- | kernel/trace/trace_kprobe.c | 18 |
1 files changed, 17 insertions, 1 deletions
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)) { |