Patch "perf thread_map: Use readdir() instead of deprecated readdir_r()" has been added to the 4.4-stable tree

Patch "perf thread_map: Use readdir() instead of deprecated readdir_r()" has been added to the 4.4-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    perf thread_map: Use readdir() instead of deprecated readdir_r()

to the 4.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     perf-thread_map-use-readdir-instead-of-deprecated-readdir_r.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 3354cf71104de49326d19d2f9bdb1f66eea52ef4 Mon Sep 17 00:00:00 2001
From: Arnaldo Carvalho de Melo <acme@redhat.com>
Date: Fri, 8 Apr 2016 11:31:24 -0300
Subject: perf thread_map: Use readdir() instead of deprecated readdir_r()

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 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
@@ -93,7 +93,7 @@ struct thread_map *thread_map__new_by_ui
 	DIR *proc;
 	int max_threads = 32, items, i;
 	char path[NAME_MAX + 1 + 6];
-	struct dirent dirent, *next, **namelist = NULL;
+	struct dirent *dirent, **namelist = NULL;
 	struct thread_map *threads = thread_map__alloc(max_threads);
 
 	if (threads == NULL)
@@ -106,16 +106,16 @@ struct thread_map *thread_map__new_by_ui
 	threads->nr = 0;
 	atomic_set(&threads->refcnt, 1);
 
-	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;


Patches currently in stable-queue which might be from acme@redhat.com are

queue-4.4/perf-tools-use-readdir-instead-of-deprecated-readdir_r.patch
queue-4.4/perf-thread_map-correctly-size-buffer-used-with-dirent-dt_name.patch
queue-4.4/perf-tests-remove-wrong-semicolon-in-while-loop-in-cqm-test.patch
queue-4.4/perf-annotate-browser-fix-behaviour-of-shift-tab-with-nothing-focussed.patch
queue-4.4/perf-tests-avoid-possible-truncation-with-dirent-d_name-snprintf.patch
queue-4.4/perf-top-use-__fallthrough.patch
queue-4.4/perf-scripting-perl-fix-compile-error-with-some-perl5-versions.patch
queue-4.4/perf-bench-numa-avoid-possible-truncation-when-using-snprintf.patch
queue-4.4/perf-tools-use-readdir-instead-of-deprecated-readdir_r-again.patch
queue-4.4/perf-thread_map-use-readdir-instead-of-deprecated-readdir_r.patch
queue-4.4/perf-tools-remove-duplicate-const-qualifier.patch
queue-4.4/tools-string-use-__fallthrough-in-perf_atoll.patch
queue-4.4/perf-intel-pt-use-__fallthrough.patch
queue-4.4/perf-script-use-readdir-instead-of-deprecated-readdir_r.patch
queue-4.4/tools-include-add-a-__fallthrough-statement.patch
queue-4.4/tools-strfilter-use-__fallthrough.patch
queue-4.4/perf-dwarf-guard-x86_64-definitions-under-ifdef-else-clause.patch
queue-4.4/perf-pmu-fix-misleadingly-indented-assignment-whitespace.patch
queue-4.4/perf-trace-do-not-process-perf_record_lost-twice.patch