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authorSamuel Thibault <samuel.thibault@ens-lyon.org>2020-06-07 02:03:45 +0000
committerSamuel Thibault <samuel.thibault@ens-lyon.org>2020-06-07 13:35:54 +0200
commitd6d74ec16c77126c59db264ebfa04d08d5b4c5c0 (patch)
tree95fded09b6a9d8ce35273d43c3f8e3d960bd0554 /sysdeps/pthread/tst-create-detached.c
parentbe22a151f3e2c2e4b9127d4fa30b269f30a7ea2e (diff)
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htl: Enable more tests
* htl/Makefile: Remove rules adding libpthread.so and libpthread.a to link
lines.
* nptl/Makefile: Move rules adding libpthread.so and libpthread.a to
link lines to...
* sysdeps/pthread/Makefile: ... here.

* nptl/eintr.c, tst-align.c tst-align3.c tst-atfork1.c tst-backtrace1.c
tst-bad-schedattr.c tst-cancel-self-canceltype.c tst-cancel-self-cleanup.c
tst-cancel-self-testcancel.c tst-cancel1.c tst-cancel10.c tst-cancel12.c
tst-cancel14.c tst-cancel15.c tst-cancel18.c tst-cancel19.c tst-cancel2.c
tst-cancel22.c tst-cancel23.c tst-cancel26.c tst-cancel27.c tst-cancel28.c
tst-cancel3.c tst-cancel8.c tst-cancelx1.c tst-cancelx10.c tst-cancelx12.c
tst-cancelx14.c tst-cancelx15.c tst-cancelx18.c tst-cancelx2.c tst-cancelx3.c
tst-cancelx8.c tst-cleanup0.c tst-cleanup0.expect tst-cleanup1.c tst-cleanup2.c
tst-cleanup3.c tst-cleanupx0.c tst-cleanupx0.expect tst-cleanupx1.c
tst-cleanupx2.c tst-cleanupx3.c tst-clock1.c tst-create-detached.c tst-detach1.c
tst-eintr2.c tst-eintr3.c tst-eintr4.c tst-eintr5.c tst-exec1.c tst-exec2.c
tst-exec3.c tst-exit1.c tst-exit2.c tst-exit3.c tst-flock1.c tst-fork1.c
tst-fork2.c tst-fork3.c tst-fork4.c tst-getpid3.c tst-kill1.c tst-kill2.c
tst-kill3.c tst-kill4.c tst-kill5.c tst-kill6.c tst-locale1.c tst-locale2.c
tst-memstream.c tst-popen1.c tst-raise1.c tst-sem5.c tst-setuid3.c tst-signal4.c
tst-signal5.c tst-signal6.c tst-signal8.c tst-stack1.c tst-stdio1.c tst-stdio2.c
tst-sysconf.c tst-tls1.c tst-tls2.c tst-tsd1.c tst-tsd2.c tst-tsd5.c tst-tsd6.c
tst-umask1.c tst-unload.c tst-unwind-thread.c tst-vfork1.c tst-vfork1x.c
tst-vfork2.c tst-vfork2x.c: Move tests to...
* sysdeps/pthread: ... here.
Rename
tst-popen1.c -> tst-pt-popen1.c
tst-align.c -> tst-pt-align.c
tst-align3.c -> tst-pt-align3.c
tst-sysconf.c -> tst-pt-sysconf.c
tst-tls1.c -> tst-pt-tls1.c
tst-tls2.c -> tst-pt-tls2.c
tst-vfork1.c -> tst-pt-vfork1.c
tst-vfork2.c -> tst-pt-vfork2.c
to avoid conflicting with libio/tst-popen1.c, elf/tst-align.c,
posix/tst-sysconf.c, elf/tst-tls1.c, elf/tst-tls2.c, posix/tst-vfork1.c,
posix/tst-vfork2.c.

* nptl/Makefile: Move corresponding tests references and special rules to...
* sysdeps/pthread/Makefile: ... here.

* sysdeps/pthread/tst-stack1.c (do_test): Do not clamp stack size to
PTHREAD_STACK_MIN if not defined.

Tested on linux-x86_64 and hurd-i386
Diffstat (limited to 'sysdeps/pthread/tst-create-detached.c')
-rw-r--r--sysdeps/pthread/tst-create-detached.c138
1 files changed, 138 insertions, 0 deletions
diff --git a/sysdeps/pthread/tst-create-detached.c b/sysdeps/pthread/tst-create-detached.c
new file mode 100644
index 0000000000..cd79c68908
--- /dev/null
+++ b/sysdeps/pthread/tst-create-detached.c
@@ -0,0 +1,138 @@
+/* Bug 20116: Test rapid creation of detached threads.
+   Copyright (C) 2017-2020 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; see the file COPYING.LIB.  If
+   not, see <https://www.gnu.org/licenses/>.  */
+
+/* The goal of the test is to trigger a failure if the parent touches
+   any part of the thread descriptor after the detached thread has
+   exited.  We test this by creating many detached threads with large
+   stacks.  The stacks quickly fill the the stack cache and subsequent
+   threads will start to cause the thread stacks to be immediately
+   unmapped to satisfy the stack cache max.  With the stacks being
+   unmapped the parent's read of any part of the thread descriptor will
+   trigger a segfault.  That segfault is what we are trying to cause,
+   since any segfault is a defect in the implementation.  */
+
+#include <pthread.h>
+#include <stdio.h>
+#include <errno.h>
+#include <unistd.h>
+#include <stdbool.h>
+#include <sys/resource.h>
+#include <support/xthread.h>
+
+/* Number of threads to create.  */
+enum { threads_to_create = 100000 };
+
+/* Number of threads which should spawn other threads.  */
+enum { creator_threads  = 2 };
+
+/* Counter of threads created so far.  This is incremented by all the
+   running creator threads.  */
+static unsigned threads_created;
+
+/* Thread callback which does nothing, so that the thread exits
+   immediatedly.  */
+static void *
+do_nothing (void *arg)
+{
+  return NULL;
+}
+
+/* Attribute indicating that the thread should be created in a detached
+   fashion.  */
+static pthread_attr_t detached;
+
+/* Barrier to synchronize initialization.  */
+static pthread_barrier_t barrier;
+
+static void *
+creator_thread (void *arg)
+{
+  int ret;
+  xpthread_barrier_wait (&barrier);
+
+  while (true)
+    {
+      pthread_t thr;
+      /* Thread creation will fail if the kernel does not free old
+	 threads quickly enough, so we do not report errors.  */
+      ret = pthread_create (&thr, &detached, do_nothing, NULL);
+      if (ret == 0 && __atomic_add_fetch (&threads_created, 1, __ATOMIC_SEQ_CST)
+          >= threads_to_create)
+        break;
+    }
+
+  return NULL;
+}
+
+static int
+do_test (void)
+{
+  /* Limit the size of the process, so that memory allocation will
+     fail without impacting the entire system.  */
+  {
+    struct rlimit limit;
+    if (getrlimit (RLIMIT_AS, &limit) != 0)
+      {
+        printf ("FAIL: getrlimit (RLIMIT_AS) failed: %m\n");
+        return 1;
+      }
+    /* This limit, 800MB, is just a heuristic. Any value can be
+       picked.  */
+    long target = 800 * 1024 * 1024;
+    if (limit.rlim_cur == RLIM_INFINITY || limit.rlim_cur > target)
+      {
+        limit.rlim_cur = target;
+        if (setrlimit (RLIMIT_AS, &limit) != 0)
+          {
+            printf ("FAIL: setrlimit (RLIMIT_AS) failed: %m\n");
+            return 1;
+          }
+      }
+  }
+
+  xpthread_attr_init (&detached);
+
+  xpthread_attr_setdetachstate (&detached, PTHREAD_CREATE_DETACHED);
+
+  /* A large thread stack seems beneficial for reproducing a race
+     condition in detached thread creation.  The goal is to reach the
+     limit of the runtime thread stack cache such that the detached
+     thread's stack is unmapped after exit and causes a segfault when
+     the parent reads the thread descriptor data stored on the the
+     unmapped stack.  */
+  xpthread_attr_setstacksize (&detached, 16 * 1024 * 1024);
+
+  xpthread_barrier_init (&barrier, NULL, creator_threads);
+
+  pthread_t threads[creator_threads];
+
+  for (int i = 0; i < creator_threads; ++i)
+    threads[i] = xpthread_create (NULL, creator_thread, NULL);
+
+  for (int i = 0; i < creator_threads; ++i)
+    xpthread_join (threads[i]);
+
+  xpthread_attr_destroy (&detached);
+
+  xpthread_barrier_destroy (&barrier);
+
+  return 0;
+}
+
+#define TIMEOUT 100
+#include <support/test-driver.c>