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Subject[PATCH 161/161] perf symbols: Fix a mmap and munmap mismatched bug
Date
From: Chenggang Qin <chenggang.qcg@taobao.com>

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
mmapped areas exist during the life of perf.

This is a memory leak. This patch fixed this bug.

Reviewed-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Chenggang Qin <chenggang.qcg@taobao.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Chenggang Qin <chenggang.qcg@taobao.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Yanmin Zhang <yanmin.zhang@intel.com>
Link: http://lkml.kernel.org/r/1381451279-4109-1-git-send-email-chenggang.qin@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
tools/perf/util/symbol-elf.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c
index d6b8af3ce344..eed0b96302af 100644
--- a/tools/perf/util/symbol-elf.c
+++ b/tools/perf/util/symbol-elf.c
@@ -487,27 +487,27 @@ 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:
--
1.8.1.4


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