Re: [PATCH] perf report: Fix a wrong offset issue when using /proc/kcore

From: Arnaldo Carvalho de Melo
Date: Thu Jan 04 2018 - 13:41:34 EST

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Em Sat, Dec 30, 2017 at 12:26:52AM +0800, Jin Yao escreveu:
> When valid vmlinux is not found, perf report falls back to look
> at /proc/kcore. While in this case, it will report the impossible
> large offset. For example,

Thanks, tested and applied!

- Arnaldo

> 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
>
> Signed-off-by: Jin Yao <yao.jin@xxxxxxxxxxxxxxx>
> ---
> 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 @@ static struct inline_node *addr2inlines(const char *dso_name, u64 addr,
> #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 @@ char *__get_srcline(struct dso *dso, u64 addr, struct symbol *sym,
>
> 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 */
> --
> 2.7.4

Next message: Kees Cook: "Re: [kernel-hardening] [PATCH] arm: Always use REFCOUNT_FULL"
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