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[PATCH perf/core v2 0/4] perf-probe: Fix and improve module probe events

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  [PATCH perf/core v2 0/4] perf-probe: Fix and improve module probe events Masami Hiramatsu <mhiramat@kernel.org> - 2017-01-11 07:00 +0100
    [PATCH perf/core v2 3/4] perf-probe: Fix to probe on gcc generated functions in modules Masami Hiramatsu <mhiramat@kernel.org> - 2017-01-11 07:10 +0100
      [tip:perf/urgent] perf probe: Fix to probe on gcc generated  functions in modules tip-bot for Masami Hiramatsu <tipbot@zytor.com> - 2017-01-18 10:30 +0100
    [PATCH perf/core v2 1/4] perf-probe: Fix to show correct locations for events on modules Masami Hiramatsu <mhiramat@kernel.org> - 2017-01-11 07:10 +0100
      Re: [PATCH perf/core v2 1/4] perf-probe: Fix to show correct  locations for events on modules Arnaldo Carvalho de Melo <acme@kernel.org> - 2017-01-16 19:40 +0100
      [tip:perf/urgent] perf probe: Fix to show correct locations for  events on modules tip-bot for Masami Hiramatsu <tipbot@zytor.com> - 2017-01-18 11:00 +0100
    [PATCH perf/core v2 4/4] perf-probe: Find probe events without target module Masami Hiramatsu <mhiramat@kernel.org> - 2017-01-11 07:10 +0100
      Re: [PATCH perf/core v2 4/4] perf-probe: Find probe events without  target module Arnaldo Carvalho de Melo <acme@kernel.org> - 2017-01-16 19:50 +0100
        Re: [PATCH perf/core v2 4/4] perf-probe: Find probe events without  target module Masami Hiramatsu <mhiramat@kernel.org> - 2017-01-16 23:30 +0100
    [PATCH perf/core v2 2/4] perf-probe: Add error checks to offline probe post-processing Masami Hiramatsu <mhiramat@kernel.org> - 2017-01-11 07:10 +0100
      [tip:perf/urgent] perf probe: Add error checks to offline probe  post-processing tip-bot for Masami Hiramatsu <tipbot@zytor.com> - 2017-01-18 10:30 +0100
    Re: [PATCH perf/core v2 0/4] perf-probe: Fix and improve module  probe events Masami Hiramatsu <mhiramat@kernel.org> - 2017-01-16 09:10 +0100

#1556216 — [PATCH perf/core v2 0/4] perf-probe: Fix and improve module probe events

Hello,

This is the 2nd version of the series for fixing offline/online
module probe support and improving perf-probe to probe module
without -m option (Thanks Arnaldo!).
This includes below patches.

 - [1/4] Fix perf-probe --list to show correct probe location
         in module.
 - [2/4] Improve error checking for the probes for offline
         kernel.
 - [3/4] Fix perf-probe to probe correctly on gcc generated
         functions in module.
 - [4/4] Improve perf-probe to find probe events in module
         without -m option.

In this version, I updated the patch description of 1/4 
and fix a bug in 4/4.

Thank you,

---

Masami Hiramatsu (4):
      perf-probe: Fix to show correct locations for events on modules
      perf-probe: Add error checks to offline probe post-processing
      perf-probe: Fix to probe on gcc generated functions in modules
      perf-probe: Find probe events without target module


 tools/perf/util/probe-event.c  |  160 ++++++++++++++++++++++++++++------------
 tools/perf/util/probe-finder.c |   15 ++--
 tools/perf/util/probe-finder.h |    3 +
 3 files changed, 121 insertions(+), 57 deletions(-)

--
Masami Hiramatsu (Linaro)

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#1556217 — [PATCH perf/core v2 3/4] perf-probe: Fix to probe on gcc generated functions in modules

Fix to probe on gcc generated functions on modules. Since
probing on a module is based on its symbol name, it should
be adjusted on actual symbols.

E.g. without this fix, perf probe shows probe definition
on non-exist symbol as below.

  $ perf probe -m build-x86_64/net/netfilter/nf_nat.ko -F in_range*
  in_range.isra.12
  $ perf probe -m build-x86_64/net/netfilter/nf_nat.ko -D in_range
  p:probe/in_range nf_nat:in_range+0

With this fix, perf probe correctly shows a probe on
gcc-generated symbol.

  $ perf probe -m build-x86_64/net/netfilter/nf_nat.ko -D in_range
  p:probe/in_range nf_nat:in_range.isra.12+0

This also fixes same problem on online module as below.

  $ perf probe -m i915 -D assert_plane
  p:probe/assert_plane i915:assert_plane.constprop.134+0

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
---
 tools/perf/util/probe-event.c  |   45 ++++++++++++++++++++++++++--------------
 tools/perf/util/probe-finder.c |    7 ++++--
 tools/perf/util/probe-finder.h |    3 +++
 3 files changed, 37 insertions(+), 18 deletions(-)

diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index aa8a922..6a6f44d 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -698,18 +698,31 @@ static int add_exec_to_probe_trace_events(struct probe_trace_event *tevs,
 	return ret;
 }
 
-static int add_module_to_probe_trace_events(struct probe_trace_event *tevs,
-					    int ntevs, const char *module)
+static int
+post_process_module_probe_trace_events(struct probe_trace_event *tevs,
+				       int ntevs, const char *module,
+				       struct debuginfo *dinfo)
 {
+	Dwarf_Addr text_offs = 0;
 	int i, ret = 0;
 	char *mod_name = NULL;
+	struct map *map;
 
 	if (!module)
 		return 0;
 
-	mod_name = find_module_name(module);
+	map = get_target_map(module, false);
+	if (!map || debuginfo__get_text_offset(dinfo, &text_offs, true) < 0) {
+		pr_warning("Failed to get ELF symbols for %s\n", module);
+		return -EINVAL;
+	}
 
+	mod_name = find_module_name(module);
 	for (i = 0; i < ntevs; i++) {
+		ret = post_process_probe_trace_point(&tevs[i].point,
+						map, (unsigned long)text_offs);
+		if (ret < 0)
+			break;
 		tevs[i].point.module =
 			strdup(mod_name ? mod_name : module);
 		if (!tevs[i].point.module) {
@@ -719,6 +732,8 @@ static int add_module_to_probe_trace_events(struct probe_trace_event *tevs,
 	}
 
 	free(mod_name);
+	map__put(map);
+
 	return ret;
 }
 
@@ -776,7 +791,7 @@ arch__post_process_probe_trace_events(struct perf_probe_event *pev __maybe_unuse
 static int post_process_probe_trace_events(struct perf_probe_event *pev,
 					   struct probe_trace_event *tevs,
 					   int ntevs, const char *module,
-					   bool uprobe)
+					   bool uprobe, struct debuginfo *dinfo)
 {
 	int ret;
 
@@ -784,7 +799,8 @@ static int post_process_probe_trace_events(struct perf_probe_event *pev,
 		ret = add_exec_to_probe_trace_events(tevs, ntevs, module);
 	else if (module)
 		/* Currently ref_reloc_sym based probe is not for drivers */
-		ret = add_module_to_probe_trace_events(tevs, ntevs, module);
+		ret = post_process_module_probe_trace_events(tevs, ntevs,
+							     module, dinfo);
 	else
 		ret = post_process_kernel_probe_trace_events(tevs, ntevs);
 
@@ -828,30 +844,27 @@ static int try_to_find_probe_trace_events(struct perf_probe_event *pev,
 		}
 	}
 
-	debuginfo__delete(dinfo);
-
 	if (ntevs > 0) {	/* Succeeded to find trace events */
 		pr_debug("Found %d probe_trace_events.\n", ntevs);
 		ret = post_process_probe_trace_events(pev, *tevs, ntevs,
-						pev->target, pev->uprobes);
+					pev->target, pev->uprobes, dinfo);
 		if (ret < 0 || ret == ntevs) {
+			pr_debug("Post processing failed or all events are skipped. (%d)\n", ret);
 			clear_probe_trace_events(*tevs, ntevs);
 			zfree(tevs);
+			ntevs = 0;
 		}
-		if (ret != ntevs)
-			return ret < 0 ? ret : ntevs;
-		ntevs = 0;
-		/* Fall through */
 	}
 
+	debuginfo__delete(dinfo);
+
 	if (ntevs == 0)	{	/* No error but failed to find probe point. */
 		pr_warning("Probe point '%s' not found.\n",
 			   synthesize_perf_probe_point(&pev->point));
 		return -ENOENT;
-	}
-	/* Error path : ntevs < 0 */
-	pr_debug("An error occurred in debuginfo analysis (%d).\n", ntevs);
-	if (ntevs < 0) {
+	} else if (ntevs < 0) {
+		/* Error path : ntevs < 0 */
+		pr_debug("An error occurred in debuginfo analysis (%d).\n", ntevs);
 		if (ntevs == -EBADF)
 			pr_warning("Warning: No dwarf info found in the vmlinux - "
 				"please rebuild kernel with CONFIG_DEBUG_INFO=y.\n");
diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
index 0278fe1..0d9d6e0 100644
--- a/tools/perf/util/probe-finder.c
+++ b/tools/perf/util/probe-finder.c
@@ -1501,7 +1501,8 @@ int debuginfo__find_available_vars_at(struct debuginfo *dbg,
 }
 
 /* For the kernel module, we need a special code to get a DIE */
-static int debuginfo__get_text_offset(struct debuginfo *dbg, Dwarf_Addr *offs)
+int debuginfo__get_text_offset(struct debuginfo *dbg, Dwarf_Addr *offs,
+				bool adjust_offset)
 {
 	int n, i;
 	Elf32_Word shndx;
@@ -1530,6 +1531,8 @@ static int debuginfo__get_text_offset(struct debuginfo *dbg, Dwarf_Addr *offs)
 			if (!shdr)
 				return -ENOENT;
 			*offs = shdr->sh_addr;
+			if (adjust_offset)
+				*offs -= shdr->sh_offset;
 		}
 	}
 	return 0;
@@ -1545,7 +1548,7 @@ int debuginfo__find_probe_point(struct debuginfo *dbg, unsigned long addr,
 	int baseline = 0, lineno = 0, ret = 0;
 
 	/* We always need to relocate the address for aranges */
-	if (debuginfo__get_text_offset(dbg, &baseaddr) == 0)
+	if (debuginfo__get_text_offset(dbg, &baseaddr, false) == 0)
 		addr += baseaddr;
 	/* Find cu die */
 	if (!dwarf_addrdie(dbg->dbg, (Dwarf_Addr)addr, &cudie)) {
diff --git a/tools/perf/util/probe-finder.h b/tools/perf/util/probe-finder.h
index f1d8558..2956c51 100644
--- a/tools/perf/util/probe-finder.h
+++ b/tools/perf/util/probe-finder.h
@@ -46,6 +46,9 @@ int debuginfo__find_trace_events(struct debuginfo *dbg,
 int debuginfo__find_probe_point(struct debuginfo *dbg, unsigned long addr,
 				struct perf_probe_point *ppt);
 
+int debuginfo__get_text_offset(struct debuginfo *dbg, Dwarf_Addr *offs,
+			       bool adjust_offset);
+
 /* Find a line range */
 int debuginfo__find_line_range(struct debuginfo *dbg, struct line_range *lr);
 

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#1561374 — [tip:perf/urgent] perf probe: Fix to probe on gcc generated functions in modules

Commit-ID:  613f050d68a8ed3c0b18b9568698908ef7bbc1f7
Gitweb:     http://git.kernel.org/tip/613f050d68a8ed3c0b18b9568698908ef7bbc1f7
Author:     Masami Hiramatsu <mhiramat@kernel.org>
AuthorDate: Wed, 11 Jan 2017 15:01:57 +0900
Committer:  Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Mon, 16 Jan 2017 15:43:04 -0300

perf probe: Fix to probe on gcc generated functions in modules

Fix to probe on gcc generated functions on modules. Since
probing on a module is based on its symbol name, it should
be adjusted on actual symbols.

E.g. without this fix, perf probe shows probe definition
on non-exist symbol as below.

  $ perf probe -m build-x86_64/net/netfilter/nf_nat.ko -F in_range*
  in_range.isra.12
  $ perf probe -m build-x86_64/net/netfilter/nf_nat.ko -D in_range
  p:probe/in_range nf_nat:in_range+0

With this fix, perf probe correctly shows a probe on
gcc-generated symbol.

  $ perf probe -m build-x86_64/net/netfilter/nf_nat.ko -D in_range
  p:probe/in_range nf_nat:in_range.isra.12+0

This also fixes same problem on online module as below.

  $ perf probe -m i915 -D assert_plane
  p:probe/assert_plane i915:assert_plane.constprop.134+0

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.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/148411450673.9978.14905987549651656075.stgit@devbox
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/util/probe-event.c  | 45 +++++++++++++++++++++++++++---------------
 tools/perf/util/probe-finder.c |  7 +++++--
 tools/perf/util/probe-finder.h |  3 +++
 3 files changed, 37 insertions(+), 18 deletions(-)

diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index aa8a922..6a6f44d 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -698,18 +698,31 @@ static int add_exec_to_probe_trace_events(struct probe_trace_event *tevs,
 	return ret;
 }
 
-static int add_module_to_probe_trace_events(struct probe_trace_event *tevs,
-					    int ntevs, const char *module)
+static int
+post_process_module_probe_trace_events(struct probe_trace_event *tevs,
+				       int ntevs, const char *module,
+				       struct debuginfo *dinfo)
 {
+	Dwarf_Addr text_offs = 0;
 	int i, ret = 0;
 	char *mod_name = NULL;
+	struct map *map;
 
 	if (!module)
 		return 0;
 
-	mod_name = find_module_name(module);
+	map = get_target_map(module, false);
+	if (!map || debuginfo__get_text_offset(dinfo, &text_offs, true) < 0) {
+		pr_warning("Failed to get ELF symbols for %s\n", module);
+		return -EINVAL;
+	}
 
+	mod_name = find_module_name(module);
 	for (i = 0; i < ntevs; i++) {
+		ret = post_process_probe_trace_point(&tevs[i].point,
+						map, (unsigned long)text_offs);
+		if (ret < 0)
+			break;
 		tevs[i].point.module =
 			strdup(mod_name ? mod_name : module);
 		if (!tevs[i].point.module) {
@@ -719,6 +732,8 @@ static int add_module_to_probe_trace_events(struct probe_trace_event *tevs,
 	}
 
 	free(mod_name);
+	map__put(map);
+
 	return ret;
 }
 
@@ -776,7 +791,7 @@ arch__post_process_probe_trace_events(struct perf_probe_event *pev __maybe_unuse
 static int post_process_probe_trace_events(struct perf_probe_event *pev,
 					   struct probe_trace_event *tevs,
 					   int ntevs, const char *module,
-					   bool uprobe)
+					   bool uprobe, struct debuginfo *dinfo)
 {
 	int ret;
 
@@ -784,7 +799,8 @@ static int post_process_probe_trace_events(struct perf_probe_event *pev,
 		ret = add_exec_to_probe_trace_events(tevs, ntevs, module);
 	else if (module)
 		/* Currently ref_reloc_sym based probe is not for drivers */
-		ret = add_module_to_probe_trace_events(tevs, ntevs, module);
+		ret = post_process_module_probe_trace_events(tevs, ntevs,
+							     module, dinfo);
 	else
 		ret = post_process_kernel_probe_trace_events(tevs, ntevs);
 
@@ -828,30 +844,27 @@ static int try_to_find_probe_trace_events(struct perf_probe_event *pev,
 		}
 	}
 
-	debuginfo__delete(dinfo);
-
 	if (ntevs > 0) {	/* Succeeded to find trace events */
 		pr_debug("Found %d probe_trace_events.\n", ntevs);
 		ret = post_process_probe_trace_events(pev, *tevs, ntevs,
-						pev->target, pev->uprobes);
+					pev->target, pev->uprobes, dinfo);
 		if (ret < 0 || ret == ntevs) {
+			pr_debug("Post processing failed or all events are skipped. (%d)\n", ret);
 			clear_probe_trace_events(*tevs, ntevs);
 			zfree(tevs);
+			ntevs = 0;
 		}
-		if (ret != ntevs)
-			return ret < 0 ? ret : ntevs;
-		ntevs = 0;
-		/* Fall through */
 	}
 
+	debuginfo__delete(dinfo);
+
 	if (ntevs == 0)	{	/* No error but failed to find probe point. */
 		pr_warning("Probe point '%s' not found.\n",
 			   synthesize_perf_probe_point(&pev->point));
 		return -ENOENT;
-	}
-	/* Error path : ntevs < 0 */
-	pr_debug("An error occurred in debuginfo analysis (%d).\n", ntevs);
-	if (ntevs < 0) {
+	} else if (ntevs < 0) {
+		/* Error path : ntevs < 0 */
+		pr_debug("An error occurred in debuginfo analysis (%d).\n", ntevs);
 		if (ntevs == -EBADF)
 			pr_warning("Warning: No dwarf info found in the vmlinux - "
 				"please rebuild kernel with CONFIG_DEBUG_INFO=y.\n");
diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
index 0278fe1..0d9d6e0 100644
--- a/tools/perf/util/probe-finder.c
+++ b/tools/perf/util/probe-finder.c
@@ -1501,7 +1501,8 @@ int debuginfo__find_available_vars_at(struct debuginfo *dbg,
 }
 
 /* For the kernel module, we need a special code to get a DIE */
-static int debuginfo__get_text_offset(struct debuginfo *dbg, Dwarf_Addr *offs)
+int debuginfo__get_text_offset(struct debuginfo *dbg, Dwarf_Addr *offs,
+				bool adjust_offset)
 {
 	int n, i;
 	Elf32_Word shndx;
@@ -1530,6 +1531,8 @@ static int debuginfo__get_text_offset(struct debuginfo *dbg, Dwarf_Addr *offs)
 			if (!shdr)
 				return -ENOENT;
 			*offs = shdr->sh_addr;
+			if (adjust_offset)
+				*offs -= shdr->sh_offset;
 		}
 	}
 	return 0;
@@ -1545,7 +1548,7 @@ int debuginfo__find_probe_point(struct debuginfo *dbg, unsigned long addr,
 	int baseline = 0, lineno = 0, ret = 0;
 
 	/* We always need to relocate the address for aranges */
-	if (debuginfo__get_text_offset(dbg, &baseaddr) == 0)
+	if (debuginfo__get_text_offset(dbg, &baseaddr, false) == 0)
 		addr += baseaddr;
 	/* Find cu die */
 	if (!dwarf_addrdie(dbg->dbg, (Dwarf_Addr)addr, &cudie)) {
diff --git a/tools/perf/util/probe-finder.h b/tools/perf/util/probe-finder.h
index f1d8558..2956c51 100644
--- a/tools/perf/util/probe-finder.h
+++ b/tools/perf/util/probe-finder.h
@@ -46,6 +46,9 @@ int debuginfo__find_trace_events(struct debuginfo *dbg,
 int debuginfo__find_probe_point(struct debuginfo *dbg, unsigned long addr,
 				struct perf_probe_point *ppt);
 
+int debuginfo__get_text_offset(struct debuginfo *dbg, Dwarf_Addr *offs,
+			       bool adjust_offset);
+
 /* Find a line range */
 int debuginfo__find_line_range(struct debuginfo *dbg, struct line_range *lr);
 

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#1556219 — [PATCH perf/core v2 1/4] perf-probe: Fix to show correct locations for events on modules

Fix to show correct locations for events on modules by relocating
given address instead of retrying after failure.

This happens when the module text size is enough big, bigger than
sh_addr, because original code retries withgiven address + sh_addr
if it failed to find CU DIE at the given address. Any address
smaller than sh_addr always fails and it retries with correct
address, but the address which bigger than sh_addr will get a CU
DIE which is on given address (not adjusted by sh_addr).

In my environment(x86-64), the sh_addr of ".text" section is
0x10030. Since i915 is a huge kernel module, we can see this
issue as below.

  $ grep "[Tt] .*\[i915\]" /proc/kallsyms | sort | head -n1
  ffffffffc0270000 t i915_switcheroo_can_switch	[i915]

ffffffffc0270000 + 0x10030 = ffffffffc0280030, so we'll check
symbols cross this boundary.

  $ grep "[Tt] .*\[i915\]" /proc/kallsyms | grep -B1 ^ffffffffc028\
  | head -n 2
  ffffffffc027ff80 t haswell_init_clock_gating	[i915]
  ffffffffc0280110 t valleyview_init_clock_gating	[i915]

So setup probes on both function and see what happen.

  $ sudo ./perf probe -m i915 -a haswell_init_clock_gating \
        -a valleyview_init_clock_gating
  Added new events:
    probe:haswell_init_clock_gating (on haswell_init_clock_gating in i915)
    probe:valleyview_init_clock_gating (on valleyview_init_clock_gating in i915)

  You can now use it in all perf tools, such as:

  	perf record -e probe:valleyview_init_clock_gating -aR sleep 1

  $ sudo ./perf probe -l
    probe:haswell_init_clock_gating (on haswell_init_clock_gating@gpu/drm/i915/intel_pm.c in i915)
    probe:valleyview_init_clock_gating (on i915_vga_set_decode:4@gpu/drm/i915/i915_drv.c in i915)

As you can see, haswell_init_clock_gating is correctly shown,
but valleyview_init_clock_gating is not.

With this patch, both events are shown correctly.

  $ sudo ./perf probe -l
    probe:haswell_init_clock_gating (on haswell_init_clock_gating@gpu/drm/i915/intel_pm.c in i915)
    probe:valleyview_init_clock_gating (on valleyview_init_clock_gating@gpu/drm/i915/intel_pm.c in i915)

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
---
  Changes in v2:
    - Rewrite patch description with precise instructions.
---
 tools/perf/util/probe-finder.c |   10 +++-------
 1 file changed, 3 insertions(+), 7 deletions(-)

diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
index df4debe..0278fe1 100644
--- a/tools/perf/util/probe-finder.c
+++ b/tools/perf/util/probe-finder.c
@@ -1543,16 +1543,12 @@ int debuginfo__find_probe_point(struct debuginfo *dbg, unsigned long addr,
 	Dwarf_Addr _addr = 0, baseaddr = 0;
 	const char *fname = NULL, *func = NULL, *basefunc = NULL, *tmp;
 	int baseline = 0, lineno = 0, ret = 0;
-	bool reloc = false;
 
-retry:
+	/* We always need to relocate the address for aranges */
+	if (debuginfo__get_text_offset(dbg, &baseaddr) == 0)
+		addr += baseaddr;
 	/* Find cu die */
 	if (!dwarf_addrdie(dbg->dbg, (Dwarf_Addr)addr, &cudie)) {
-		if (!reloc && debuginfo__get_text_offset(dbg, &baseaddr) == 0) {
-			addr += baseaddr;
-			reloc = true;
-			goto retry;
-		}
 		pr_warning("Failed to find debug information for address %lx\n",
 			   addr);
 		ret = -EINVAL;

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#1559972 — Re: [PATCH perf/core v2 1/4] perf-probe: Fix to show correct locations for events on modules

Em Wed, Jan 11, 2017 at 02:59:38PM +0900, Masami Hiramatsu escreveu:
> Fix to show correct locations for events on modules by relocating
> given address instead of retrying after failure.
> 
> This happens when the module text size is enough big, bigger than
> sh_addr, because original code retries withgiven address + sh_addr
> if it failed to find CU DIE at the given address. Any address
> smaller than sh_addr always fails and it retries with correct
> address, but the address which bigger than sh_addr will get a CU
> DIE which is on given address (not adjusted by sh_addr).

Tested and applied,

- Arnaldo

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#1561423 — [tip:perf/urgent] perf probe: Fix to show correct locations for events on modules

Commit-ID:  d2d4edbebe07ddb77980656abe7b9bc7a9e0cdf7
Gitweb:     http://git.kernel.org/tip/d2d4edbebe07ddb77980656abe7b9bc7a9e0cdf7
Author:     Masami Hiramatsu <mhiramat@kernel.org>
AuthorDate: Wed, 11 Jan 2017 14:59:38 +0900
Committer:  Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Mon, 16 Jan 2017 15:14:06 -0300

perf probe: Fix to show correct locations for events on modules

Fix to show correct locations for events on modules by relocating given
address instead of retrying after failure.

This happens when the module text size is big enough, bigger than
sh_addr, because the original code retries with given address + sh_addr
if it failed to find CU DIE at the given address.

Any address smaller than sh_addr always fails and it retries with the
correct address, but addresses bigger than sh_addr will get a CU DIE
which is on the given address (not adjusted by sh_addr).

In my environment(x86-64), the sh_addr of ".text" section is 0x10030.
Since i915 is a huge kernel module, we can see this issue as below.

  $ grep "[Tt] .*\[i915\]" /proc/kallsyms | sort | head -n1
  ffffffffc0270000 t i915_switcheroo_can_switch	[i915]

ffffffffc0270000 + 0x10030 = ffffffffc0280030, so we'll check
symbols cross this boundary.

  $ grep "[Tt] .*\[i915\]" /proc/kallsyms | grep -B1 ^ffffffffc028\
  | head -n 2
  ffffffffc027ff80 t haswell_init_clock_gating	[i915]
  ffffffffc0280110 t valleyview_init_clock_gating	[i915]

So setup probes on both function and see what happen.

  $ sudo ./perf probe -m i915 -a haswell_init_clock_gating \
        -a valleyview_init_clock_gating
  Added new events:
    probe:haswell_init_clock_gating (on haswell_init_clock_gating in i915)
    probe:valleyview_init_clock_gating (on valleyview_init_clock_gating in i915)

  You can now use it in all perf tools, such as:

  	perf record -e probe:valleyview_init_clock_gating -aR sleep 1

  $ sudo ./perf probe -l
    probe:haswell_init_clock_gating (on haswell_init_clock_gating@gpu/drm/i915/intel_pm.c in i915)
    probe:valleyview_init_clock_gating (on i915_vga_set_decode:4@gpu/drm/i915/i915_drv.c in i915)

As you can see, haswell_init_clock_gating is correctly shown,
but valleyview_init_clock_gating is not.

With this patch, both events are shown correctly.

  $ sudo ./perf probe -l
    probe:haswell_init_clock_gating (on haswell_init_clock_gating@gpu/drm/i915/intel_pm.c in i915)
    probe:valleyview_init_clock_gating (on valleyview_init_clock_gating@gpu/drm/i915/intel_pm.c in i915)

Committer notes:

In my case:

  # perf probe -m i915 -a haswell_init_clock_gating -a valleyview_init_clock_gating
  Added new events:
    probe:haswell_init_clock_gating (on haswell_init_clock_gating in i915)
    probe:valleyview_init_clock_gating (on valleyview_init_clock_gating in i915)

  You can now use it in all perf tools, such as:

	  perf record -e probe:valleyview_init_clock_gating -aR sleep 1

  # perf probe -l
    probe:haswell_init_clock_gating (on i915_getparam+432@gpu/drm/i915/i915_drv.c in i915)
    probe:valleyview_init_clock_gating (on __i915_printk+240@gpu/drm/i915/i915_drv.c in i915)
  #

  # readelf -SW /lib/modules/4.9.0+/build/vmlinux | egrep -w '.text|Name'
   [Nr] Name   Type      Address          Off    Size   ES Flg Lk Inf Al
   [ 1] .text  PROGBITS  ffffffff81000000 200000 822fd3 00  AX  0   0 4096
  #

  So both are b0rked, now with the fix:

  # perf probe -m i915 -a haswell_init_clock_gating -a valleyview_init_clock_gating
  Added new events:
    probe:haswell_init_clock_gating (on haswell_init_clock_gating in i915)
    probe:valleyview_init_clock_gating (on valleyview_init_clock_gating in i915)

  You can now use it in all perf tools, such as:

	perf record -e probe:valleyview_init_clock_gating -aR sleep 1

  # perf probe -l
    probe:haswell_init_clock_gating (on haswell_init_clock_gating@gpu/drm/i915/intel_pm.c in i915)
    probe:valleyview_init_clock_gating (on valleyview_init_clock_gating@gpu/drm/i915/intel_pm.c in i915)
  #

Both looks correct.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.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/148411436777.9978.1440275861947194930.stgit@devbox
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/util/probe-finder.c | 10 +++-------
 1 file changed, 3 insertions(+), 7 deletions(-)

diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
index df4debe..0278fe1 100644
--- a/tools/perf/util/probe-finder.c
+++ b/tools/perf/util/probe-finder.c
@@ -1543,16 +1543,12 @@ int debuginfo__find_probe_point(struct debuginfo *dbg, unsigned long addr,
 	Dwarf_Addr _addr = 0, baseaddr = 0;
 	const char *fname = NULL, *func = NULL, *basefunc = NULL, *tmp;
 	int baseline = 0, lineno = 0, ret = 0;
-	bool reloc = false;
 
-retry:
+	/* We always need to relocate the address for aranges */
+	if (debuginfo__get_text_offset(dbg, &baseaddr) == 0)
+		addr += baseaddr;
 	/* Find cu die */
 	if (!dwarf_addrdie(dbg->dbg, (Dwarf_Addr)addr, &cudie)) {
-		if (!reloc && debuginfo__get_text_offset(dbg, &baseaddr) == 0) {
-			addr += baseaddr;
-			reloc = true;
-			goto retry;
-		}
 		pr_warning("Failed to find debug information for address %lx\n",
 			   addr);
 		ret = -EINVAL;

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#1556220 — [PATCH perf/core v2 4/4] perf-probe: Find probe events without target module

Find probe events without -m "module" option. If perf-probe
failed to find given function in kernel image, it tries to
find same symbol and module in kallsyms, and retry search
in the found module. E.g.

  # perf probe -D i915_capabilities
  p:probe/i915_capabilities i915:i915_capabilities+0

Note: without -m option, perf probe can not find inlined
function since there is no symbol information in kallsyms.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Suggested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
  Changes in v2:
   - Fix to remove unneeded zero-return.
   - Remove unneeded debug message.
---
 tools/perf/util/probe-event.c |   69 ++++++++++++++++++++++++++++++-----------
 1 file changed, 51 insertions(+), 18 deletions(-)

diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index 6a6f44d..715f330 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -858,11 +858,7 @@ static int try_to_find_probe_trace_events(struct perf_probe_event *pev,
 
 	debuginfo__delete(dinfo);
 
-	if (ntevs == 0)	{	/* No error but failed to find probe point. */
-		pr_warning("Probe point '%s' not found.\n",
-			   synthesize_perf_probe_point(&pev->point));
-		return -ENOENT;
-	} else if (ntevs < 0) {
+	if (ntevs < 0) {
 		/* Error path : ntevs < 0 */
 		pr_debug("An error occurred in debuginfo analysis (%d).\n", ntevs);
 		if (ntevs == -EBADF)
@@ -2829,9 +2825,7 @@ static int find_probe_trace_events_from_map(struct perf_probe_event *pev,
 	 */
 	num_matched_functions = find_probe_functions(map, pp->function, syms);
 	if (num_matched_functions == 0) {
-		pr_err("Failed to find symbol %s in %s\n", pp->function,
-			pev->target ? : "kernel");
-		ret = -ENOENT;
+		ret = 0;
 		goto out;
 	} else if (num_matched_functions > probe_conf.max_probes) {
 		pr_err("Too many functions matched in %s\n",
@@ -3233,6 +3227,42 @@ static int find_probe_trace_events_from_cache(struct perf_probe_event *pev,
 	return ret;
 }
 
+static int __convert_to_probe_trace_events(struct perf_probe_event *pev,
+					   struct probe_trace_event **tevs)
+{
+	int ret;
+
+	/* At first, we need to lookup cache entry */
+	ret = find_probe_trace_events_from_cache(pev, tevs);
+	if (ret > 0 || pev->sdt)	/* SDT can be found only in the cache */
+		return ret == 0 ? -ENOENT : ret; /* Found in probe cache */
+
+	/* Convert perf_probe_event with debuginfo */
+	ret = try_to_find_probe_trace_events(pev, tevs);
+	if (ret != 0)
+		return ret;	/* Found in debuginfo or got an error */
+
+	return find_probe_trace_events_from_map(pev, tevs);
+}
+
+static char *find_module_from_kallsyms(const char *symbol_name)
+{
+	struct machine *machine = machine__new_kallsyms();
+	struct symbol *sym;
+	struct map *map;
+	char *module;
+
+	sym = machine__find_kernel_function_by_name(machine, symbol_name, &map);
+	if (!sym || map->dso->short_name[0] != '[')
+		return NULL;
+	pr_debug("Found %s in %s\n", sym->name, map->dso->short_name);
+	module = strdup(map->dso->short_name + 1);
+	if (module)
+		module[strlen(module) - 1] = '\0';
+
+	return module;
+}
+
 static int convert_to_probe_trace_events(struct perf_probe_event *pev,
 					 struct probe_trace_event **tevs)
 {
@@ -3255,17 +3285,20 @@ static int convert_to_probe_trace_events(struct perf_probe_event *pev,
 	if (ret > 0)
 		return ret;
 
-	/* At first, we need to lookup cache entry */
-	ret = find_probe_trace_events_from_cache(pev, tevs);
-	if (ret > 0 || pev->sdt)	/* SDT can be found only in the cache */
-		return ret == 0 ? -ENOENT : ret; /* Found in probe cache */
-
-	/* Convert perf_probe_event with debuginfo */
-	ret = try_to_find_probe_trace_events(pev, tevs);
-	if (ret != 0)
-		return ret;	/* Found in debuginfo or got an error */
+	ret = __convert_to_probe_trace_events(pev, tevs);
+	/* Not found. will retry to check kmodule if possible */
+	if (ret == 0 && !pev->uprobes && !pev->target) {
+		pev->target = find_module_from_kallsyms(pev->point.function);
+		if (pev->target)
+			ret = __convert_to_probe_trace_events(pev, tevs);
+	}
 
-	return find_probe_trace_events_from_map(pev, tevs);
+	if (ret == 0) {
+		pr_warning("Probe point '%s' not found.\n",
+			   synthesize_perf_probe_point(&pev->point));
+		ret = -ENOENT;
+	}
+	return ret;
 }
 
 int convert_perf_probe_events(struct perf_probe_event *pevs, int npevs)

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#1559977 — Re: [PATCH perf/core v2 4/4] perf-probe: Find probe events without target module

Em Wed, Jan 11, 2017 at 03:03:06PM +0900, Masami Hiramatsu escreveu:
> Find probe events without -m "module" option. If perf-probe
> failed to find given function in kernel image, it tries to
> find same symbol and module in kallsyms, and retry search
> in the found module. E.g.
> 
>   # perf probe -D i915_capabilities
>   p:probe/i915_capabilities i915:i915_capabilities+0
> 
> Note: without -m option, perf probe can not find inlined
> function since there is no symbol information in kallsyms.

As this is a new feature, I'll postpone merging it till we get
perf/urgent, with the first three patches in this series, merged into
perf/core, ok?

- Arnaldo
 
> Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
> Suggested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
> ---
>   Changes in v2:
>    - Fix to remove unneeded zero-return.
>    - Remove unneeded debug message.
> ---
>  tools/perf/util/probe-event.c |   69 ++++++++++++++++++++++++++++++-----------
>  1 file changed, 51 insertions(+), 18 deletions(-)
> 
> diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
> index 6a6f44d..715f330 100644
> --- a/tools/perf/util/probe-event.c
> +++ b/tools/perf/util/probe-event.c
> @@ -858,11 +858,7 @@ static int try_to_find_probe_trace_events(struct perf_probe_event *pev,
>  
>  	debuginfo__delete(dinfo);
>  
> -	if (ntevs == 0)	{	/* No error but failed to find probe point. */
> -		pr_warning("Probe point '%s' not found.\n",
> -			   synthesize_perf_probe_point(&pev->point));
> -		return -ENOENT;
> -	} else if (ntevs < 0) {
> +	if (ntevs < 0) {
>  		/* Error path : ntevs < 0 */
>  		pr_debug("An error occurred in debuginfo analysis (%d).\n", ntevs);
>  		if (ntevs == -EBADF)
> @@ -2829,9 +2825,7 @@ static int find_probe_trace_events_from_map(struct perf_probe_event *pev,
>  	 */
>  	num_matched_functions = find_probe_functions(map, pp->function, syms);
>  	if (num_matched_functions == 0) {
> -		pr_err("Failed to find symbol %s in %s\n", pp->function,
> -			pev->target ? : "kernel");
> -		ret = -ENOENT;
> +		ret = 0;
>  		goto out;
>  	} else if (num_matched_functions > probe_conf.max_probes) {
>  		pr_err("Too many functions matched in %s\n",
> @@ -3233,6 +3227,42 @@ static int find_probe_trace_events_from_cache(struct perf_probe_event *pev,
>  	return ret;
>  }
>  
> +static int __convert_to_probe_trace_events(struct perf_probe_event *pev,
> +					   struct probe_trace_event **tevs)
> +{
> +	int ret;
> +
> +	/* At first, we need to lookup cache entry */
> +	ret = find_probe_trace_events_from_cache(pev, tevs);
> +	if (ret > 0 || pev->sdt)	/* SDT can be found only in the cache */
> +		return ret == 0 ? -ENOENT : ret; /* Found in probe cache */
> +
> +	/* Convert perf_probe_event with debuginfo */
> +	ret = try_to_find_probe_trace_events(pev, tevs);
> +	if (ret != 0)
> +		return ret;	/* Found in debuginfo or got an error */
> +
> +	return find_probe_trace_events_from_map(pev, tevs);
> +}
> +
> +static char *find_module_from_kallsyms(const char *symbol_name)
> +{
> +	struct machine *machine = machine__new_kallsyms();
> +	struct symbol *sym;
> +	struct map *map;
> +	char *module;
> +
> +	sym = machine__find_kernel_function_by_name(machine, symbol_name, &map);
> +	if (!sym || map->dso->short_name[0] != '[')
> +		return NULL;
> +	pr_debug("Found %s in %s\n", sym->name, map->dso->short_name);
> +	module = strdup(map->dso->short_name + 1);
> +	if (module)
> +		module[strlen(module) - 1] = '\0';
> +
> +	return module;
> +}
> +
>  static int convert_to_probe_trace_events(struct perf_probe_event *pev,
>  					 struct probe_trace_event **tevs)
>  {
> @@ -3255,17 +3285,20 @@ static int convert_to_probe_trace_events(struct perf_probe_event *pev,
>  	if (ret > 0)
>  		return ret;
>  
> -	/* At first, we need to lookup cache entry */
> -	ret = find_probe_trace_events_from_cache(pev, tevs);
> -	if (ret > 0 || pev->sdt)	/* SDT can be found only in the cache */
> -		return ret == 0 ? -ENOENT : ret; /* Found in probe cache */
> -
> -	/* Convert perf_probe_event with debuginfo */
> -	ret = try_to_find_probe_trace_events(pev, tevs);
> -	if (ret != 0)
> -		return ret;	/* Found in debuginfo or got an error */
> +	ret = __convert_to_probe_trace_events(pev, tevs);
> +	/* Not found. will retry to check kmodule if possible */
> +	if (ret == 0 && !pev->uprobes && !pev->target) {
> +		pev->target = find_module_from_kallsyms(pev->point.function);
> +		if (pev->target)
> +			ret = __convert_to_probe_trace_events(pev, tevs);
> +	}
>  
> -	return find_probe_trace_events_from_map(pev, tevs);
> +	if (ret == 0) {
> +		pr_warning("Probe point '%s' not found.\n",
> +			   synthesize_perf_probe_point(&pev->point));
> +		ret = -ENOENT;
> +	}
> +	return ret;
>  }
>  
>  int convert_perf_probe_events(struct perf_probe_event *pevs, int npevs)

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#1560139 — Re: [PATCH perf/core v2 4/4] perf-probe: Find probe events without target module

On Mon, 16 Jan 2017 15:44:55 -0300
Arnaldo Carvalho de Melo <acme@kernel.org> wrote:

> Em Wed, Jan 11, 2017 at 03:03:06PM +0900, Masami Hiramatsu escreveu:
> > Find probe events without -m "module" option. If perf-probe
> > failed to find given function in kernel image, it tries to
> > find same symbol and module in kallsyms, and retry search
> > in the found module. E.g.
> > 
> >   # perf probe -D i915_capabilities
> >   p:probe/i915_capabilities i915:i915_capabilities+0
> > 
> > Note: without -m option, perf probe can not find inlined
> > function since there is no symbol information in kallsyms.
> 
> As this is a new feature, I'll postpone merging it till we get
> perf/urgent, with the first three patches in this series, merged into
> perf/core, ok?

Agreed :-)

Thank you!

> 
> - Arnaldo
>  
> > Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
> > Suggested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
> > ---
> >   Changes in v2:
> >    - Fix to remove unneeded zero-return.
> >    - Remove unneeded debug message.
> > ---
> >  tools/perf/util/probe-event.c |   69 ++++++++++++++++++++++++++++++-----------
> >  1 file changed, 51 insertions(+), 18 deletions(-)
> > 
> > diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
> > index 6a6f44d..715f330 100644
> > --- a/tools/perf/util/probe-event.c
> > +++ b/tools/perf/util/probe-event.c
> > @@ -858,11 +858,7 @@ static int try_to_find_probe_trace_events(struct perf_probe_event *pev,
> >  
> >  	debuginfo__delete(dinfo);
> >  
> > -	if (ntevs == 0)	{	/* No error but failed to find probe point. */
> > -		pr_warning("Probe point '%s' not found.\n",
> > -			   synthesize_perf_probe_point(&pev->point));
> > -		return -ENOENT;
> > -	} else if (ntevs < 0) {
> > +	if (ntevs < 0) {
> >  		/* Error path : ntevs < 0 */
> >  		pr_debug("An error occurred in debuginfo analysis (%d).\n", ntevs);
> >  		if (ntevs == -EBADF)
> > @@ -2829,9 +2825,7 @@ static int find_probe_trace_events_from_map(struct perf_probe_event *pev,
> >  	 */
> >  	num_matched_functions = find_probe_functions(map, pp->function, syms);
> >  	if (num_matched_functions == 0) {
> > -		pr_err("Failed to find symbol %s in %s\n", pp->function,
> > -			pev->target ? : "kernel");
> > -		ret = -ENOENT;
> > +		ret = 0;
> >  		goto out;
> >  	} else if (num_matched_functions > probe_conf.max_probes) {
> >  		pr_err("Too many functions matched in %s\n",
> > @@ -3233,6 +3227,42 @@ static int find_probe_trace_events_from_cache(struct perf_probe_event *pev,
> >  	return ret;
> >  }
> >  
> > +static int __convert_to_probe_trace_events(struct perf_probe_event *pev,
> > +					   struct probe_trace_event **tevs)
> > +{
> > +	int ret;
> > +
> > +	/* At first, we need to lookup cache entry */
> > +	ret = find_probe_trace_events_from_cache(pev, tevs);
> > +	if (ret > 0 || pev->sdt)	/* SDT can be found only in the cache */
> > +		return ret == 0 ? -ENOENT : ret; /* Found in probe cache */
> > +
> > +	/* Convert perf_probe_event with debuginfo */
> > +	ret = try_to_find_probe_trace_events(pev, tevs);
> > +	if (ret != 0)
> > +		return ret;	/* Found in debuginfo or got an error */
> > +
> > +	return find_probe_trace_events_from_map(pev, tevs);
> > +}
> > +
> > +static char *find_module_from_kallsyms(const char *symbol_name)
> > +{
> > +	struct machine *machine = machine__new_kallsyms();
> > +	struct symbol *sym;
> > +	struct map *map;
> > +	char *module;
> > +
> > +	sym = machine__find_kernel_function_by_name(machine, symbol_name, &map);
> > +	if (!sym || map->dso->short_name[0] != '[')
> > +		return NULL;
> > +	pr_debug("Found %s in %s\n", sym->name, map->dso->short_name);
> > +	module = strdup(map->dso->short_name + 1);
> > +	if (module)
> > +		module[strlen(module) - 1] = '\0';
> > +
> > +	return module;
> > +}
> > +
> >  static int convert_to_probe_trace_events(struct perf_probe_event *pev,
> >  					 struct probe_trace_event **tevs)
> >  {
> > @@ -3255,17 +3285,20 @@ static int convert_to_probe_trace_events(struct perf_probe_event *pev,
> >  	if (ret > 0)
> >  		return ret;
> >  
> > -	/* At first, we need to lookup cache entry */
> > -	ret = find_probe_trace_events_from_cache(pev, tevs);
> > -	if (ret > 0 || pev->sdt)	/* SDT can be found only in the cache */
> > -		return ret == 0 ? -ENOENT : ret; /* Found in probe cache */
> > -
> > -	/* Convert perf_probe_event with debuginfo */
> > -	ret = try_to_find_probe_trace_events(pev, tevs);
> > -	if (ret != 0)
> > -		return ret;	/* Found in debuginfo or got an error */
> > +	ret = __convert_to_probe_trace_events(pev, tevs);
> > +	/* Not found. will retry to check kmodule if possible */
> > +	if (ret == 0 && !pev->uprobes && !pev->target) {
> > +		pev->target = find_module_from_kallsyms(pev->point.function);
> > +		if (pev->target)
> > +			ret = __convert_to_probe_trace_events(pev, tevs);
> > +	}
> >  
> > -	return find_probe_trace_events_from_map(pev, tevs);
> > +	if (ret == 0) {
> > +		pr_warning("Probe point '%s' not found.\n",
> > +			   synthesize_perf_probe_point(&pev->point));
> > +		ret = -ENOENT;
> > +	}
> > +	return ret;
> >  }
> >  
> >  int convert_perf_probe_events(struct perf_probe_event *pevs, int npevs)


-- 
Masami Hiramatsu <mhiramat@kernel.org>

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#1556221 — [PATCH perf/core v2 2/4] perf-probe: Add error checks to offline probe post-processing

Add error check codes to post process and improve it for
offline probe events as;
 - post process fails if no matched symbol found in map(-ENOENT)
   or strdup() failed(-ENOMEM).
 - Even if the symbol name is same, it updates symbol address
   and offset.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
---
 tools/perf/util/probe-event.c |   50 +++++++++++++++++++++++++++--------------
 1 file changed, 33 insertions(+), 17 deletions(-)

diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index 4a57c8a..aa8a922 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -610,6 +610,33 @@ static int find_perf_probe_point_from_dwarf(struct probe_trace_point *tp,
 	return ret ? : -ENOENT;
 }
 
+/* Adjust symbol name and address */
+static int post_process_probe_trace_point(struct probe_trace_point *tp,
+					   struct map *map, unsigned long offs)
+{
+	struct symbol *sym;
+	u64 addr = tp->address + tp->offset - offs;
+
+	sym = map__find_symbol(map, addr);
+	if (!sym)
+		return -ENOENT;
+
+	if (strcmp(sym->name, tp->symbol)) {
+		/* If we have no realname, use symbol for it */
+		if (!tp->realname)
+			tp->realname = tp->symbol;
+		else
+			free(tp->symbol);
+		tp->symbol = strdup(sym->name);
+		if (!tp->symbol)
+			return -ENOMEM;
+	}
+	tp->offset = addr - sym->start;
+	tp->address -= offs;
+
+	return 0;
+}
+
 /*
  * Rename DWARF symbols to ELF symbols -- gcc sometimes optimizes functions
  * and generate new symbols with suffixes such as .constprop.N or .isra.N
@@ -622,11 +649,9 @@ static int
 post_process_offline_probe_trace_events(struct probe_trace_event *tevs,
 					int ntevs, const char *pathname)
 {
-	struct symbol *sym;
 	struct map *map;
 	unsigned long stext = 0;
-	u64 addr;
-	int i;
+	int i, ret = 0;
 
 	/* Prepare a map for offline binary */
 	map = dso__new_map(pathname);
@@ -636,23 +661,14 @@ post_process_offline_probe_trace_events(struct probe_trace_event *tevs,
 	}
 
 	for (i = 0; i < ntevs; i++) {
-		addr = tevs[i].point.address + tevs[i].point.offset - stext;
-		sym = map__find_symbol(map, addr);
-		if (!sym)
-			continue;
-		if (!strcmp(sym->name, tevs[i].point.symbol))
-			continue;
-		/* If we have no realname, use symbol for it */
-		if (!tevs[i].point.realname)
-			tevs[i].point.realname = tevs[i].point.symbol;
-		else
-			free(tevs[i].point.symbol);
-		tevs[i].point.symbol = strdup(sym->name);
-		tevs[i].point.offset = addr - sym->start;
+		ret = post_process_probe_trace_point(&tevs[i].point,
+						     map, stext);
+		if (ret < 0)
+			break;
 	}
 	map__put(map);
 
-	return 0;
+	return ret;
 }
 
 static int add_exec_to_probe_trace_events(struct probe_trace_event *tevs,

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#1561378 — [tip:perf/urgent] perf probe: Add error checks to offline probe post-processing

Commit-ID:  3e96dac7c956089d3f23aca98c4dfca57b6aaf8a
Gitweb:     http://git.kernel.org/tip/3e96dac7c956089d3f23aca98c4dfca57b6aaf8a
Author:     Masami Hiramatsu <mhiramat@kernel.org>
AuthorDate: Wed, 11 Jan 2017 15:00:47 +0900
Committer:  Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Mon, 16 Jan 2017 15:35:25 -0300

perf probe: Add error checks to offline probe post-processing

Add error check codes on post processing and improve it for offline
probe events as:

 - post processing fails if no matched symbol found in map(-ENOENT)
   or strdup() failed(-ENOMEM).

 - Even if the symbol name is the same, it updates symbol address
   and offset.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/148411443738.9978.4617979132625405545.stgit@devbox
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/util/probe-event.c | 50 ++++++++++++++++++++++++++++---------------
 1 file changed, 33 insertions(+), 17 deletions(-)

diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index 4a57c8a..aa8a922 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -610,6 +610,33 @@ error:
 	return ret ? : -ENOENT;
 }
 
+/* Adjust symbol name and address */
+static int post_process_probe_trace_point(struct probe_trace_point *tp,
+					   struct map *map, unsigned long offs)
+{
+	struct symbol *sym;
+	u64 addr = tp->address + tp->offset - offs;
+
+	sym = map__find_symbol(map, addr);
+	if (!sym)
+		return -ENOENT;
+
+	if (strcmp(sym->name, tp->symbol)) {
+		/* If we have no realname, use symbol for it */
+		if (!tp->realname)
+			tp->realname = tp->symbol;
+		else
+			free(tp->symbol);
+		tp->symbol = strdup(sym->name);
+		if (!tp->symbol)
+			return -ENOMEM;
+	}
+	tp->offset = addr - sym->start;
+	tp->address -= offs;
+
+	return 0;
+}
+
 /*
  * Rename DWARF symbols to ELF symbols -- gcc sometimes optimizes functions
  * and generate new symbols with suffixes such as .constprop.N or .isra.N
@@ -622,11 +649,9 @@ static int
 post_process_offline_probe_trace_events(struct probe_trace_event *tevs,
 					int ntevs, const char *pathname)
 {
-	struct symbol *sym;
 	struct map *map;
 	unsigned long stext = 0;
-	u64 addr;
-	int i;
+	int i, ret = 0;
 
 	/* Prepare a map for offline binary */
 	map = dso__new_map(pathname);
@@ -636,23 +661,14 @@ post_process_offline_probe_trace_events(struct probe_trace_event *tevs,
 	}
 
 	for (i = 0; i < ntevs; i++) {
-		addr = tevs[i].point.address + tevs[i].point.offset - stext;
-		sym = map__find_symbol(map, addr);
-		if (!sym)
-			continue;
-		if (!strcmp(sym->name, tevs[i].point.symbol))
-			continue;
-		/* If we have no realname, use symbol for it */
-		if (!tevs[i].point.realname)
-			tevs[i].point.realname = tevs[i].point.symbol;
-		else
-			free(tevs[i].point.symbol);
-		tevs[i].point.symbol = strdup(sym->name);
-		tevs[i].point.offset = addr - sym->start;
+		ret = post_process_probe_trace_point(&tevs[i].point,
+						     map, stext);
+		if (ret < 0)
+			break;
 	}
 	map__put(map);
 
-	return 0;
+	return ret;
 }
 
 static int add_exec_to_probe_trace_events(struct probe_trace_event *tevs,

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#1559505 — Re: [PATCH perf/core v2 0/4] perf-probe: Fix and improve module probe events

Ping?

Arnaldo, could you merge it if it is acceptable?

Thank you,

On Wed, 11 Jan 2017 14:58:25 +0900
Masami Hiramatsu <mhiramat@kernel.org> wrote:

> Hello,
> 
> This is the 2nd version of the series for fixing offline/online
> module probe support and improving perf-probe to probe module
> without -m option (Thanks Arnaldo!).
> This includes below patches.
> 
>  - [1/4] Fix perf-probe --list to show correct probe location
>          in module.
>  - [2/4] Improve error checking for the probes for offline
>          kernel.
>  - [3/4] Fix perf-probe to probe correctly on gcc generated
>          functions in module.
>  - [4/4] Improve perf-probe to find probe events in module
>          without -m option.
> 
> In this version, I updated the patch description of 1/4 
> and fix a bug in 4/4.
> 
> Thank you,
> 
> ---
> 
> Masami Hiramatsu (4):
>       perf-probe: Fix to show correct locations for events on modules
>       perf-probe: Add error checks to offline probe post-processing
>       perf-probe: Fix to probe on gcc generated functions in modules
>       perf-probe: Find probe events without target module
> 
> 
>  tools/perf/util/probe-event.c  |  160 ++++++++++++++++++++++++++++------------
>  tools/perf/util/probe-finder.c |   15 ++--
>  tools/perf/util/probe-finder.h |    3 +
>  3 files changed, 121 insertions(+), 57 deletions(-)
> 
> --
> Masami Hiramatsu (Linaro)


-- 
Masami Hiramatsu <mhiramat@kernel.org>

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