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Commit 5a51fcd1 authored by Masami Hiramatsu's avatar Masami Hiramatsu Committed by Arnaldo Carvalho de Melo
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perf probe: Skip kernel symbols which is out of .text 



Skip the kernel symbols which is out of .text, e.g. the functions
in .inittext. Those are found in debuginfo/kallsyms, but already
freed from memory.

e.g.
  ----
  # perf probe vfs_caches_init
  vfs_caches_init+0 is out of .text, skip it.
  Probe point 'vfs_caches_init' not found.
    Error: Failed to add events.
  ----

Signed-off-by: default avatarMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Tested-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Hemant Kumar <hemant@linux.vnet.ibm.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20150506124649.4961.56249.stgit@localhost.localdomain


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 573709fd

tools/perf/util/probe-event.c

+24 −7
Original line number Diff line number Diff line
@@ -557,8 +557,9 @@ static int post_process_probe_trace_events(struct probe_trace_event *tevs, 
					   bool uprobe)

{

	struct ref_reloc_sym *reloc_sym;

	u64 etext_addr;

	char *tmp;

	int i;

	int i, skipped = 0;



	if (uprobe)

		return add_exec_to_probe_trace_events(tevs, ntevs, module);
@@ -572,19 +573,29 @@ static int post_process_probe_trace_events(struct probe_trace_event *tevs, 
		pr_warning("Relocated base symbol is not found!\n");

		return -EINVAL;

	}

	/* Get the address of _etext for checking non-probable text symbol */

	etext_addr = kernel_get_symbol_address_by_name("_etext", false);



	for (i = 0; i < ntevs; i++) {

		if (tevs[i].point.address && !tevs[i].point.retprobe) {

			/* If we found a wrong one, mark it by NULL symbol */

			if (etext_addr < tevs[i].point.address) {

				pr_warning("%s+%lu is out of .text, skip it.\n",

				   tevs[i].point.symbol, tevs[i].point.offset);

				tmp = NULL;

				skipped++;

			} else {

				tmp = strdup(reloc_sym->name);

				if (!tmp)

					return -ENOMEM;

			}

			free(tevs[i].point.symbol);

			tevs[i].point.symbol = tmp;

			tevs[i].point.offset = tevs[i].point.address -

					       reloc_sym->unrelocated_addr;

		}

	}

	return 0;

	return skipped;

}



/* Try to find perf_probe_event with debuginfo */
@@ -630,11 +641,14 @@ static int try_to_find_probe_trace_events(struct perf_probe_event *pev, 
		pr_debug("Found %d probe_trace_events.\n", ntevs);

		ret = post_process_probe_trace_events(*tevs, ntevs,

							target, pev->uprobes);

		if (ret < 0) {

		if (ret < 0 || ret == ntevs) {

			clear_probe_trace_events(*tevs, ntevs);

			zfree(tevs);

		}

		if (ret != ntevs)

			return ret < 0 ? ret : ntevs;

		ntevs = 0;

		/* Fall through */

	}



	if (ntevs == 0)	{	/* No error but failed to find probe point. */
@@ -2403,6 +2417,9 @@ static int __add_probe_trace_events(struct perf_probe_event *pev, 
	pr_info("Added new event%s\n", (ntevs > 1) ? "s:" : ":");

	for (i = 0; i < ntevs; i++) {

		tev = &tevs[i];

		/* Skip if the symbol is out of .text (marked previously) */

		if (!tev->point.symbol)

			continue;

		/* Ensure that the address is NOT blacklisted */

		node = kprobe_blacklist__find_by_address(&blacklist,

							 tev->point.address);