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Subject[PATCH 1/1] perf symbols: Call the symbol filter in dso__synthesize_plt_symbols
Date
From: Arnaldo Carvalho de Melo <acme@redhat.com>

We need to pass the symbol to the filter so that, for instance, 'perf
top' can do filtering and also set the private area it manages, setting
the ->map pointer, etc.

I found this while running 'perf top' on a machine where hits happened
on PLT symbols, where ->map wasn't being set up and segfaults thus
happened.

Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
tools/perf/util/symbol.c | 26 ++++++++++++++++++++------
1 files changed, 20 insertions(+), 6 deletions(-)

diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index 9c286db..93e4b52 100644
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -281,6 +281,11 @@ static int kernel_maps__load_all_kallsyms(void)
if (sym == NULL)
goto out_delete_line;

+ /*
+ * We will pass the symbols to the filter later, in
+ * kernel_maps__split_kallsyms, when we have split the
+ * maps per module
+ */
dso__insert_symbol(kernel_map->dso, sym);
}

@@ -555,7 +560,8 @@ static Elf_Scn *elf_section_by_name(Elf *elf, GElf_Ehdr *ep,
* And always look at the original dso, not at debuginfo packages, that
* have the PLT data stripped out (shdr_rel_plt.sh_type == SHT_NOBITS).
*/
-static int dso__synthesize_plt_symbols(struct dso *self)
+static int dso__synthesize_plt_symbols(struct dso *self, struct map *map,
+ symbol_filter_t filter)
{
uint32_t nr_rel_entries, idx;
GElf_Sym sym;
@@ -643,8 +649,12 @@ static int dso__synthesize_plt_symbols(struct dso *self)
if (!f)
goto out_elf_end;

- dso__insert_symbol(self, f);
- ++nr;
+ if (filter && filter(map, f))
+ symbol__delete(f);
+ else {
+ dso__insert_symbol(self, f);
+ ++nr;
+ }
}
} else if (shdr_rel_plt.sh_type == SHT_REL) {
GElf_Rel pos_mem, *pos;
@@ -661,8 +671,12 @@ static int dso__synthesize_plt_symbols(struct dso *self)
if (!f)
goto out_elf_end;

- dso__insert_symbol(self, f);
- ++nr;
+ if (filter && filter(map, f))
+ symbol__delete(f);
+ else {
+ dso__insert_symbol(self, f);
+ ++nr;
+ }
}
}

@@ -1050,7 +1064,7 @@ compare_build_id:
goto more;

if (ret > 0) {
- int nr_plt = dso__synthesize_plt_symbols(self);
+ int nr_plt = dso__synthesize_plt_symbols(self, map, filter);
if (nr_plt > 0)
ret += nr_plt;
}
--
1.6.2.5


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