From 4bb11d012ab248d0e383008d725be0d26a74fac2 Mon Sep 17 00:00:00 2001 From: Namhyung Kim Date: Thu, 21 May 2015 01:03:41 +0900 Subject: [PATCH] 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. Signed-off-by: Namhyung Kim Acked-by: Adrian Hunter Cc: David Ahern Cc: Jiri Olsa Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/1432137821-10853-3-git-send-email-namhyung@kernel.org Signed-off-by: Arnaldo Carvalho de Melo --- 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)) -- 2.30.2