[tip:perf/core] perf symbols: Fix a mmap and munmap mismatched bug

[tip-bot for Chenggang Qin]

Commit-ID:  784f3390f9bd900adfb3b0373615e105a0d9749a
Gitweb:     http://git.kernel.org/tip/784f3390f9bd900adfb3b0373615e105a0d9749a
Author:     Chenggang Qin <chenggang.qcg@xxxxxxxxxx>
AuthorDate: Fri, 11 Oct 2013 08:27:57 +0800
Committer:  Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitDate: Mon, 14 Oct 2013 12:21:23 -0300

perf symbols: Fix a mmap and munmap mismatched bug

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@xxxxxxxxxx>
Signed-off-by: Chenggang Qin <chenggang.qcg@xxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Arjan van de Ven <arjan@xxxxxxxxxxxxxxx>
Cc: Chenggang Qin <chenggang.qcg@xxxxxxxxxx>
Cc: David Ahern <dsahern@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Mike Galbraith <efault@xxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: Wu Fengguang <fengguang.wu@xxxxxxxxx>
Cc: Yanmin Zhang <yanmin.zhang@xxxxxxxxx>
Link: http://lkml.kernel.org/r/1381451279-4109-1-git-send-email-chenggang.qin@xxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
 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 d6b8af3..eed0b96 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:
--
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