[tip:perf/core] perf report: Fix a wrong offset issue when using /proc/kcore

From: tip-bot for Jin Yao
Date: Thu Jan 11 2018 - 01:23:33 EST

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Commit-ID: 935f5a9d4500020879858c9224c98dfabf16101d
Gitweb: https://git.kernel.org/tip/935f5a9d4500020879858c9224c98dfabf16101d
Author: Jin Yao <yao.jin@xxxxxxxxxxxxxxx>
AuthorDate: Sat, 30 Dec 2017 00:26:52 +0800
Committer: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitDate: Mon, 8 Jan 2018 11:11:57 -0300

perf report: Fix a wrong offset issue when using /proc/kcore

When a valid vmlinux is not found, 'perf report' falls back to look at
/proc/kcore. In this case, it will report the impossible large offset.

For example:

# perf record -b -e cycles:k find /etc/ > /dev/null
# perf report --stdio --branch-history

22.77% _vm_normal_page+18446603336221188162
|
---page_remove_rmap +18446603336221188324
page_remove_rmap +18446603336221188487 (cycles:5)
unlock_page_memcg +18446603336221188096
page_remove_rmap +18446603336221188327 (cycles:1)

The issue is the value which is passed to parameter 'addr' in
__get_srcline() is the objdump address. It's not correct if we calculate
the offset by using 'addr - sym->start'.

This patch creates a new parameter 'ip' in __get_srcline(). It is not
converted to objdump address.

With this patch, the perf report output is:

22.77% _vm_normal_page+66
|
---page_remove_rmap +228
page_remove_rmap +391 (cycles:5)
unlock_page_memcg +0
page_remove_rmap +231 (cycles:1)
page_remove_rmap +236

Committer testing:

Make sure you get any valid vmlinux out of the way, using '-v' on the
'perf report' case and deleting it from places where perf searches them,
like your kernel build dir and the build-id cache, in ~/.debug/.

Reported-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Signed-off-by: Jin Yao <yao.jin@xxxxxxxxxxxxxxx>
Tested-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Cc: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Kan Liang <kan.liang@xxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/1514564812-17344-1-git-send-email-yao.jin@xxxxxxxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
tools/perf/util/annotate.c | 3 ++-
tools/perf/util/machine.c | 2 +-
tools/perf/util/map.c | 2 +-
tools/perf/util/sort.c | 16 ++++++++++------
tools/perf/util/srcline.c | 9 +++++----
tools/perf/util/srcline.h | 5 +++--
6 files changed, 22 insertions(+), 15 deletions(-)

diff --git a/tools/perf/util/annotate.c b/tools/perf/util/annotate.c
index 68e687d..28b233c 100644
--- a/tools/perf/util/annotate.c
+++ b/tools/perf/util/annotate.c
@@ -1960,7 +1960,8 @@ static void annotation__calc_lines(struct annotation *notes, struct map *map,
if (percent_max <= 0.5)
continue;

- al->path = get_srcline(map->dso, start + al->offset, NULL, false, true);
+ al->path = get_srcline(map->dso, start + al->offset, NULL,
+ false, true, start + al->offset);
insert_source_line(&tmp_root, al);
}

diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
index 64d255f..b05a674 100644
--- a/tools/perf/util/machine.c
+++ b/tools/perf/util/machine.c
@@ -1726,7 +1726,7 @@ static char *callchain_srcline(struct map *map, struct symbol *sym, u64 ip)
bool show_addr = callchain_param.key == CCKEY_ADDRESS;

srcline = get_srcline(map->dso, map__rip_2objdump(map, ip),
- sym, show_sym, show_addr);
+ sym, show_sym, show_addr, ip);
srcline__tree_insert(&map->dso->srclines, ip, srcline);
}

diff --git a/tools/perf/util/map.c b/tools/perf/util/map.c
index 6d40efd..8fe5703 100644
--- a/tools/perf/util/map.c
+++ b/tools/perf/util/map.c
@@ -419,7 +419,7 @@ int map__fprintf_srcline(struct map *map, u64 addr, const char *prefix,
if (map && map->dso) {
srcline = get_srcline(map->dso,
map__rip_2objdump(map, addr), NULL,
- true, true);
+ true, true, addr);
if (srcline != SRCLINE_UNKNOWN)
ret = fprintf(fp, "%s%s", prefix, srcline);
free_srcline(srcline);
diff --git a/tools/perf/util/sort.c b/tools/perf/util/sort.c
index a00eacd..211e7f3 100644
--- a/tools/perf/util/sort.c
+++ b/tools/perf/util/sort.c
@@ -336,7 +336,7 @@ char *hist_entry__get_srcline(struct hist_entry *he)
return SRCLINE_UNKNOWN;

return get_srcline(map->dso, map__rip_2objdump(map, he->ip),
- he->ms.sym, true, true);
+ he->ms.sym, true, true, he->ip);
}

static int64_t
@@ -380,7 +380,8 @@ sort__srcline_from_cmp(struct hist_entry *left, struct hist_entry *right)
map__rip_2objdump(map,
left->branch_info->from.al_addr),
left->branch_info->from.sym,
- true, true);
+ true, true,
+ left->branch_info->from.al_addr);
}
if (!right->branch_info->srcline_from) {
struct map *map = right->branch_info->from.map;
@@ -391,7 +392,8 @@ sort__srcline_from_cmp(struct hist_entry *left, struct hist_entry *right)
map__rip_2objdump(map,
right->branch_info->from.al_addr),
right->branch_info->from.sym,
- true, true);
+ true, true,
+ right->branch_info->from.al_addr);
}
return strcmp(right->branch_info->srcline_from, left->branch_info->srcline_from);
}
@@ -423,7 +425,8 @@ sort__srcline_to_cmp(struct hist_entry *left, struct hist_entry *right)
map__rip_2objdump(map,
left->branch_info->to.al_addr),
left->branch_info->from.sym,
- true, true);
+ true, true,
+ left->branch_info->to.al_addr);
}
if (!right->branch_info->srcline_to) {
struct map *map = right->branch_info->to.map;
@@ -434,7 +437,8 @@ sort__srcline_to_cmp(struct hist_entry *left, struct hist_entry *right)
map__rip_2objdump(map,
right->branch_info->to.al_addr),
right->branch_info->to.sym,
- true, true);
+ true, true,
+ right->branch_info->to.al_addr);
}
return strcmp(right->branch_info->srcline_to, left->branch_info->srcline_to);
}
@@ -465,7 +469,7 @@ static char *hist_entry__get_srcfile(struct hist_entry *e)
return no_srcfile;

sf = __get_srcline(map->dso, map__rip_2objdump(map, e->ip),
- e->ms.sym, false, true, true);
+ e->ms.sym, false, true, true, e->ip);
if (!strcmp(sf, SRCLINE_UNKNOWN))
return no_srcfile;
p = strchr(sf, ':');
diff --git a/tools/perf/util/srcline.c b/tools/perf/util/srcline.c
index d19f05c..3c21fd0 100644
--- a/tools/perf/util/srcline.c
+++ b/tools/perf/util/srcline.c
@@ -496,7 +496,8 @@ out:
#define A2L_FAIL_LIMIT 123

char *__get_srcline(struct dso *dso, u64 addr, struct symbol *sym,
- bool show_sym, bool show_addr, bool unwind_inlines)
+ bool show_sym, bool show_addr, bool unwind_inlines,
+ u64 ip)
{
char *file = NULL;
unsigned line = 0;
@@ -536,7 +537,7 @@ out:

if (sym) {
if (asprintf(&srcline, "%s+%" PRIu64, show_sym ? sym->name : "",
- addr - sym->start) < 0)
+ ip - sym->start) < 0)
return SRCLINE_UNKNOWN;
} else if (asprintf(&srcline, "%s[%" PRIx64 "]", dso->short_name, addr) < 0)
return SRCLINE_UNKNOWN;
@@ -550,9 +551,9 @@ void free_srcline(char *srcline)
}

char *get_srcline(struct dso *dso, u64 addr, struct symbol *sym,
- bool show_sym, bool show_addr)
+ bool show_sym, bool show_addr, u64 ip)
{
- return __get_srcline(dso, addr, sym, show_sym, show_addr, false);
+ return __get_srcline(dso, addr, sym, show_sym, show_addr, false, ip);
}

struct srcline_node {
diff --git a/tools/perf/util/srcline.h b/tools/perf/util/srcline.h
index 847b708..b2bb5502 100644
--- a/tools/perf/util/srcline.h
+++ b/tools/perf/util/srcline.h
@@ -11,9 +11,10 @@ struct symbol;

extern bool srcline_full_filename;
char *get_srcline(struct dso *dso, u64 addr, struct symbol *sym,
- bool show_sym, bool show_addr);
+ bool show_sym, bool show_addr, u64 ip);
char *__get_srcline(struct dso *dso, u64 addr, struct symbol *sym,
- bool show_sym, bool show_addr, bool unwind_inlines);
+ bool show_sym, bool show_addr, bool unwind_inlines,
+ u64 ip);
void free_srcline(char *srcline);

/* insert the srcline into the DSO, which will take ownership */

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