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Message-Id: <1432137821-10853-3-git-send-email-namhyung@kernel.org>
Date: Thu, 21 May 2015 01:03:41 +0900
From: Namhyung Kim <namhyung@...nel.org>
To: Arnaldo Carvalho de Melo <acme@...nel.org>
Cc: Ingo Molnar <mingo@...nel.org>,
Peter Zijlstra <a.p.zijlstra@...llo.nl>,
Jiri Olsa <jolsa@...hat.com>,
LKML <linux-kernel@...r.kernel.org>,
Adrian Hunter <adrian.hunter@...el.com>,
David Ahern <dsahern@...il.com>
Subject: [PATCH v2 3/3] perf tools: Add dso__data_get/put_fd()
Using dso__data_fd() in multi-thread environment is not safe since
returned fd can be closed and/or reused anytime. So convert it to the
dso__data_get/put_fd() pair to protect the access with lock.
The original dso__data_fd() is deprecated and kept only for testing.
Cc: Adrian Hunter <adrian.hunter@...el.com>
Signed-off-by: Namhyung Kim <namhyung@...nel.org>
---
tools/perf/tests/dso-data.c | 11 +++++++++++
tools/perf/util/dso.c | 31 ++++++++++++++++++++++---------
tools/perf/util/dso.h | 13 +++++++++----
tools/perf/util/unwind-libunwind.c | 11 ++++++++---
4 files changed, 50 insertions(+), 16 deletions(-)
diff --git a/tools/perf/tests/dso-data.c b/tools/perf/tests/dso-data.c
index 513e5febbe5a..3e41c61bd861 100644
--- a/tools/perf/tests/dso-data.c
+++ b/tools/perf/tests/dso-data.c
@@ -99,6 +99,17 @@ struct test_data_offset offsets[] = {
},
};
+/* move it from util/dso.c for compatibility */
+static int dso__data_fd(struct dso *dso, struct machine *machine)
+{
+ int fd = dso__data_get_fd(dso, machine);
+
+ if (fd >= 0)
+ dso__data_put_fd(dso);
+
+ return fd;
+}
+
int test__dso_data(void)
{
struct machine machine;
diff --git a/tools/perf/util/dso.c b/tools/perf/util/dso.c
index e95e850dd832..7e11a700303f 100644
--- a/tools/perf/util/dso.c
+++ b/tools/perf/util/dso.c
@@ -473,25 +473,35 @@ out:
}
/**
- * dso__data_fd - Get dso's data file descriptor
+ * dso__data_get_fd - Get dso's data file descriptor
* @dso: dso object
* @machine: machine object
*
* External interface to find dso's file, open it and
- * returns file descriptor.
+ * returns file descriptor. It should be paired with
+ * dso__data_put_fd() if it returns non-negative value.
*/
-int dso__data_fd(struct dso *dso, struct machine *machine)
+int dso__data_get_fd(struct dso *dso, struct machine *machine)
{
if (dso->data.status == DSO_DATA_STATUS_ERROR)
return -1;
- pthread_mutex_lock(&dso__data_open_lock);
+ if (pthread_mutex_lock(&dso__data_open_lock) < 0)
+ return -1;
+
try_to_open_dso(dso, machine);
- pthread_mutex_unlock(&dso__data_open_lock);
+
+ if (dso->data.fd < 0)
+ pthread_mutex_unlock(&dso__data_open_lock);
return dso->data.fd;
}
+void dso__data_put_fd(struct dso *dso __maybe_unused)
+{
+ pthread_mutex_unlock(&dso__data_open_lock);
+}
+
bool dso__data_status_seen(struct dso *dso, enum dso_data_status_seen by)
{
u32 flag = 1 << by;
@@ -1199,12 +1209,15 @@ size_t dso__fprintf(struct dso *dso, enum map_type type, FILE *fp)
enum dso_type dso__type(struct dso *dso, struct machine *machine)
{
int fd;
+ enum dso_type type = DSO__TYPE_UNKNOWN;
- fd = dso__data_fd(dso, machine);
- if (fd < 0)
- return DSO__TYPE_UNKNOWN;
+ fd = dso__data_get_fd(dso, machine);
+ if (fd >= 0) {
+ type = dso__type_fd(fd);
+ dso__data_put_fd(dso);
+ }
- return dso__type_fd(fd);
+ return type;
}
int dso__strerror_load(struct dso *dso, char *buf, size_t buflen)
diff --git a/tools/perf/util/dso.h b/tools/perf/util/dso.h
index b26ec3ab1336..bcec06ad73a2 100644
--- a/tools/perf/util/dso.h
+++ b/tools/perf/util/dso.h
@@ -240,7 +240,8 @@ int __kmod_path__parse(struct kmod_path *m, const char *path,
/*
* The dso__data_* external interface provides following functions:
- * dso__data_fd
+ * dso__data_get_fd
+ * dso__data_put_fd
* dso__data_close
* dso__data_size
* dso__data_read_offset
@@ -257,8 +258,11 @@ int __kmod_path__parse(struct kmod_path *m, const char *path,
* The current usage of the dso__data_* interface is as follows:
*
* Get DSO's fd:
- * int fd = dso__data_fd(dso, machine);
- * USE 'fd' SOMEHOW
+ * int fd = dso__data_get_fd(dso, machine);
+ * if (fd >= 0) {
+ * USE 'fd' SOMEHOW
+ * dso__data_put_fd(dso);
+ * }
*
* Read DSO's data:
* n = dso__data_read_offset(dso_0, &machine, 0, buf, BUFSIZE);
@@ -277,7 +281,8 @@ int __kmod_path__parse(struct kmod_path *m, const char *path,
*
* TODO
*/
-int dso__data_fd(struct dso *dso, struct machine *machine);
+int dso__data_get_fd(struct dso *dso, struct machine *machine);
+void dso__data_put_fd(struct dso *dso __maybe_unused);
void dso__data_close(struct dso *dso);
off_t dso__data_size(struct dso *dso, struct machine *machine);
diff --git a/tools/perf/util/unwind-libunwind.c b/tools/perf/util/unwind-libunwind.c
index 7b09a443a280..f079b63f0b7f 100644
--- a/tools/perf/util/unwind-libunwind.c
+++ b/tools/perf/util/unwind-libunwind.c
@@ -269,13 +269,14 @@ static int read_unwind_spec_eh_frame(struct dso *dso, struct machine *machine,
u64 offset = dso->data.eh_frame_hdr_offset;
if (offset == 0) {
- fd = dso__data_fd(dso, machine);
+ fd = dso__data_get_fd(dso, machine);
if (fd < 0)
return -EINVAL;
/* Check the .eh_frame section for unwinding info */
offset = elf_section_offset(fd, ".eh_frame_hdr");
dso->data.eh_frame_hdr_offset = offset;
+ dso__data_put_fd(dso);
}
if (offset)
@@ -294,13 +295,14 @@ static int read_unwind_spec_debug_frame(struct dso *dso,
u64 ofs = dso->data.debug_frame_offset;
if (ofs == 0) {
- fd = dso__data_fd(dso, machine);
+ fd = dso__data_get_fd(dso, machine);
if (fd < 0)
return -EINVAL;
/* Check the .debug_frame section for unwinding info */
ofs = elf_section_offset(fd, ".debug_frame");
dso->data.debug_frame_offset = ofs;
+ dso__data_put_fd(dso);
}
*offset = ofs;
@@ -353,10 +355,13 @@ find_proc_info(unw_addr_space_t as, unw_word_t ip, unw_proc_info_t *pi,
#ifndef NO_LIBUNWIND_DEBUG_FRAME
/* Check the .debug_frame section for unwinding info */
if (!read_unwind_spec_debug_frame(map->dso, ui->machine, &segbase)) {
- int fd = dso__data_fd(map->dso, ui->machine);
+ int fd = dso__data_get_fd(map->dso, ui->machine);
int is_exec = elf_is_exec(fd, map->dso->name);
unw_word_t base = is_exec ? 0 : map->start;
+ if (fd >= 0)
+ dso__data_put_fd(dso);
+
memset(&di, 0, sizeof(di));
if (dwarf_find_debug_frame(0, &di, ip, base, map->dso->name,
map->start, map->end))
--
2.4.0
--
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