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Message-Id: <1432103647-14017-4-git-send-email-namhyung@kernel.org>
Date: Wed, 20 May 2015 15:34:07 +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>,
David Ahern <dsahern@...il.com>,
Adrian Hunter <adrian.hunter@...el.com>
Subject: [PATCH 4/4] 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/util/dso.c | 44 +++++++++++++++++++++++++++++---------
tools/perf/util/dso.h | 9 ++++++--
tools/perf/util/unwind-libunwind.c | 38 +++++++++++++++++++-------------
3 files changed, 64 insertions(+), 27 deletions(-)
diff --git a/tools/perf/util/dso.c b/tools/perf/util/dso.c
index 21fae6908717..5227e41925c2 100644
--- a/tools/perf/util/dso.c
+++ b/tools/perf/util/dso.c
@@ -471,27 +471,49 @@ static void try_to_open_dso(struct dso *dso, struct machine *machine)
}
/**
- * 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. Should be paired with
+ * dso__data_put_fd().
*/
-int dso__data_fd(struct dso *dso, struct machine *machine)
+int dso__data_get_fd(struct dso *dso, struct machine *machine)
{
+ pthread_mutex_lock(&dso__data_open_lock);
+
if (dso->data.status == DSO_DATA_STATUS_ERROR)
return -1;
- pthread_mutex_lock(&dso__data_open_lock);
-
if (dso->data.fd < 0)
try_to_open_dso(dso, machine);
- 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);
+}
+
+/**
+ * dso__data_get_fd - Get dso's data file descriptor
+ * @dso: dso object
+ * @machine: machine object
+ *
+ * Obsolete interface to find dso's file, open it and
+ * returns file descriptor. It's not thread-safe in that
+ * the returned fd may be reused for other file.
+ */
+int dso__data_fd(struct dso *dso, struct machine *machine)
+{
+ int fd = dso__data_get_fd(dso, machine);
+
+ dso__data_put_fd(dso);
+ return fd;
+}
+
bool dso__data_status_seen(struct dso *dso, enum dso_data_status_seen by)
{
u32 flag = 1 << by;
@@ -1198,12 +1220,14 @@ 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..de9d98c44ae2 100644
--- a/tools/perf/util/dso.h
+++ b/tools/perf/util/dso.h
@@ -240,7 +240,9 @@ int __kmod_path__parse(struct kmod_path *m, const char *path,
/*
* The dso__data_* external interface provides following functions:
- * dso__data_fd
+ * dso__data_fd (obsolete)
+ * dso__data_get_fd
+ * dso__data_put_fd
* dso__data_close
* dso__data_size
* dso__data_read_offset
@@ -257,8 +259,9 @@ 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);
+ * int fd = dso__data_get_fd(dso, machine);
* USE 'fd' SOMEHOW
+ * dso__data_put_fd(dso)
*
* Read DSO's data:
* n = dso__data_read_offset(dso_0, &machine, 0, buf, BUFSIZE);
@@ -278,6 +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);
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..6d4ab3251729 100644
--- a/tools/perf/util/unwind-libunwind.c
+++ b/tools/perf/util/unwind-libunwind.c
@@ -269,13 +269,13 @@ 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);
- 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;
+ fd = dso__data_get_fd(dso, machine);
+ if (fd >= 0) {
+ /* 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 +294,19 @@ 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);
- 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;
+ int ret = 0;
+
+ fd = dso__data_get_fd(dso, machine);
+ if (fd >= 0) {
+ /* Check the .debug_frame section for unwinding info */
+ ofs = elf_section_offset(fd, ".debug_frame");
+ dso->data.debug_frame_offset = ofs;
+ } else
+ ret = -EINVAL;
+
+ dso__data_put_fd(dso);
+ if (ret)
+ return ret;
}
*offset = ofs;
@@ -353,10 +359,12 @@ 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;
+ dso__data_put_fd(map->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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