[PATCH 1/3] perf core: Fix a mmap and munmap mismatched bug

From: Chenggang Qin
Date: Sun Sep 01 2013 - 11:30:42 EST


From: root <root@xxxxxxxxxxxxxxxxxx>

In function filename__read_debuglink(), while the ELF file is opend and mmapped
in elf_begin(), but if this file is considered to not be usable during the
following code, we will goto the close(fd) directly. The elf_end() is skipped.
So, the mmaped ELF file cannot be munmapped. The memory areas are mmapped is
exist during the life of perf. This is a memory leak.
This patch fixed this bug.
Thanks.

Cc: David Ahern <dsahern@xxxxxxxxx>
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxxxxxxxxxx>
Cc: Arjan van de Ven <arjan@xxxxxxxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxx>
Cc: Yanmin Zhang <yanmin.zhang@xxxxxxxxx>
Cc: Wu Fengguang <fengguang.wu@xxxxxxxxx>
Cc: Mike Galbraith <efault@xxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Chenggang Qin <chenggang.qcg@xxxxxxxxxx>

---
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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