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Subject[PATCH] perf core: Fix a bug that lead to mmap() & munmap() mismatch
Date
From: Chenggang Qin <chenggang.qcg@taobao.com>

In function filename__read_debuglink(), after the elf_begin() mmapped the dso file,
the execution stream may goto "out_close". So, the elf_end() is skipped, and the
munmap() cannot be executed.

While perf is executed for a long time, the files that are not munmapped will cost
a large memory.

This patch fixed this bug.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: Chenggang Qin <chenggang.qcg@taobao.com>
---
tools/perf/util/symbol-elf.c | 10 +++++-----
1 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c
index 4b12bf8..b4df870 100644
--- a/tools/perf/util/symbol-elf.c
+++ b/tools/perf/util/symbol-elf.c
@@ -471,27 +471,27 @@ int filename__read_debuglink(const char *filename, char *debuglink,

ek = elf_kind(elf);
if (ek != ELF_K_ELF)
- goto out_close;
+ goto out_elf_end;

if (gelf_getehdr(elf, &ehdr) == NULL) {
pr_err("%s: cannot get elf header.\n", __func__);
- goto out_close;
+ goto out_elf_end;
}

sec = elf_section_by_name(elf, &ehdr, &shdr,
".gnu_debuglink", NULL);
if (sec == NULL)
- goto out_close;
+ goto out_elf_end;

data = elf_getdata(sec, NULL);
if (data == NULL)
- goto out_close;
+ goto out_elf_end;

/* the start of this section is a zero-terminated string */
strncpy(debuglink, data->d_buf, size);

+out_elf_end:
elf_end(elf);
-
out_close:
close(fd);
out:
--
1.7.8.rc2.5.g815b


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