3.16.61-rc1 review patch. If anyone has any objections, please let me know.
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From: Arnaldo Carvalho de Melo acme@redhat.com
commit 3354cf71104de49326d19d2f9bdb1f66eea52ef4 upstream.
The readdir() function is thread safe as long as just one thread uses a DIR, which is the case in thread_map, so, to avoid breaking the build with glibc-2.23.90 (upcoming 2.24), use it instead of readdir_r().
See: http://man7.org/linux/man-pages/man3/readdir.3.html
"However, in modern implementations (including the glibc implementation), concurrent calls to readdir() that specify different directory streams are thread-safe. In cases where multiple threads must read from the same directory stream, using readdir() with external synchronization is still preferable to the use of the deprecated readdir_r(3) function."
Noticed while building on a Fedora Rawhide docker container.
Cc: Adrian Hunter adrian.hunter@intel.com Cc: David Ahern dsahern@gmail.com Cc: Jiri Olsa jolsa@kernel.org Cc: Namhyung Kim namhyung@kernel.org Cc: Wang Nan wangnan0@huawei.com Link: http://lkml.kernel.org/n/tip-del8h2a0f40z75j4r42l96l0@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo acme@redhat.com [bwh: Backported to 3.16: adjust context] Signed-off-by: Ben Hutchings ben@decadent.org.uk --- tools/perf/util/thread_map.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)
--- a/tools/perf/util/thread_map.c +++ b/tools/perf/util/thread_map.c @@ -64,7 +64,7 @@ struct thread_map *thread_map__new_by_ui DIR *proc; int max_threads = 32, items, i; char path[256]; - struct dirent dirent, *next, **namelist = NULL; + struct dirent *dirent, **namelist = NULL; struct thread_map *threads = malloc(sizeof(*threads) + max_threads * sizeof(pid_t)); if (threads == NULL) @@ -76,16 +76,16 @@ struct thread_map *thread_map__new_by_ui
threads->nr = 0;
- while (!readdir_r(proc, &dirent, &next) && next) { + while ((dirent = readdir(proc)) != NULL) { char *end; bool grow = false; struct stat st; - pid_t pid = strtol(dirent.d_name, &end, 10); + pid_t pid = strtol(dirent->d_name, &end, 10);
if (*end) /* only interested in proper numerical dirents */ continue;
- snprintf(path, sizeof(path), "/proc/%s", dirent.d_name); + snprintf(path, sizeof(path), "/proc/%s", dirent->d_name);
if (stat(path, &st) != 0) continue;