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perf/urgent 'perf probe' fixes:

Browse source 
Fixes:
 
 - Show correct locations for 'perf probe' on modules (Masami Hiramatsu)
 
 - Correctly handle 'perf probe's on gcc generated functions in modules (Masami Hiramatsu)
 
 Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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Merge tag 'perf-urgent-for-mingo-4.10-20170117' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux into perf/urgent

Pull 'perf probe' fixes from Arnaldo Carvalho de Melo <acme@redhat.com>

  - Show correct locations for 'perf probe' on modules (Masami Hiramatsu)

  - Correctly handle 'perf probe's on GCC generated functions in modules (Masami Hiramatsu)

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Ingo Molnar 2017-01-17 16:58:53 +01:00
commit 31f5260a76
3 changed files with 72 additions and 41 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

95
tools/perf/util/probe-event.c
View file

@ -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,
@ -682,18 +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) {
@ -703,6 +732,8 @@ static int add_module_to_probe_trace_events(struct probe_trace_event *tevs,
}
free(mod_name);
map__put(map);
return ret;
}
@ -760,7 +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;
@ -768,7 +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);
@ -812,30 +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");

15
tools/perf/util/probe-finder.c
View file

@ -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;
@ -1543,16 +1546,12 @@ 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, false) == 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;

3
tools/perf/util/probe-finder.h
View file

@ -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);