Short description: malloc: Test various special cases related to allocation failures

Author(s): Florian Weimer <fweimer@redhat.com>

Origin: git://sourceware.org/git/glibc.git

Bug-RHEL: #1296453 (rhel-7.2.z),  #1293976 (rhel-7.3), #1256285 (SRT)

Bug-Fedora: NA

Bug-Upstream: NA

Upstream status: committed

#

# commit 1bd5483e104c8bde6e61dc5e3f8a848bc861872d

# Author: Florian Weimer <fweimer@redhat.com>

# Date:   Tue Dec 29 20:32:35 2015 +0100

# 

#     malloc: Test various special cases related to allocation failures

#     

#     This test case exercises unusual code paths in allocation functions,

#     related to allocation failures.  Specifically, the test can reveal

#     the following bugs:

#     

#     (a) calloc returns non-zero memory on fallback to sysmalloc.

#     (b) calloc can self-deadlock because it fails to release

#         the arena lock on certain allocation failures.

#     (c) pvalloc can dereference a NULL arena pointer.

#     

#     (a) and (b) appear specific to a faulty downstream backport.

#     (c) was fixed as part of commit 10ad46bc6526edc5c7afcc57112da96917ff3629.

#     

#     The test for (a) was inspired by a reproducer supplied by Jeff Layton.

# 

Index: glibc-2.17-c758a686/malloc/Makefile

===================================================================

--- glibc-2.17-c758a686.orig/malloc/Makefile

+++ glibc-2.17-c758a686/malloc/Makefile

@@ -27,7 +27,8 @@ headers := $(dist-headers) obstack.h mch

 tests := mallocbug tst-malloc tst-valloc tst-calloc tst-obstack \

 	 tst-mallocstate tst-mcheck tst-mallocfork tst-trim1 \

 	 tst-malloc-usable \

-	 tst-malloc-backtrace tst-malloc-thread-exit

+	 tst-malloc-backtrace tst-malloc-thread-exit \

+	 tst-malloc-thread-fail

 test-srcs = tst-mtrace

 routines = malloc morecore mcheck mtrace obstack

@@ -44,6 +45,8 @@ libmemusage-inhibit-o = $(filter-out .os

 $(objpfx)tst-malloc-backtrace: $(common-objpfx)nptl/libpthread.so \

 			       $(common-objpfx)nptl/libpthread_nonshared.a

+$(objpfx)tst-malloc-thread-fail: $(common-objpfx)nptl/libpthread.so \

+			       $(common-objpfx)nptl/libpthread_nonshared.a

 $(objpfx)tst-malloc-thread-exit: $(common-objpfx)nptl/libpthread.so \

 			       $(common-objpfx)nptl/libpthread_nonshared.a

Index: glibc-2.17-c758a686/malloc/tst-malloc-thread-fail.c

===================================================================

--- /dev/null

+++ glibc-2.17-c758a686/malloc/tst-malloc-thread-fail.c

@@ -0,0 +1,468 @@

+/* Test allocation function behavior on allocation failure.

+   Copyright (C) 2015 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 <http://www.gnu.org/licenses/>.  */

+

+/* This test case attempts to trigger various unusual conditions

+   related to allocation failures, notably switching to a different

+   arena, and falling back to mmap (via sysmalloc).  */

+

+#include <errno.h>

+#include <malloc.h>

+#include <pthread.h>

+#include <stdbool.h>

+#include <stdint.h>

+#include <stdio.h>

+#include <stdlib.h>

+#include <sys/resource.h>

+#include <sys/wait.h>

+#include <unistd.h>

+#include <stddef.h>

+

+/* This mirrors the C11 max_align_t type provided by GCC, but it is

+   also available in C99 mode.  The aligned attributes are required

+   because some ABIs have reduced alignment requirements for struct

+   and union members.  */

+typedef struct {

+  long long ll __attribute__ ((__aligned__ (__alignof__ (long long))));

+  long double ld __attribute__ ((__aligned__ (__alignof__ (long double))));

+} libc_max_align_t;

+

+/* Wrapper for calloc with an optimization barrier.  */

+static void *

+__attribute__ ((noinline, noclone))

+allocate_zeroed (size_t a, size_t b)

+{

+  return calloc (a, b);

+}

+

+/* System page size, as determined by sysconf (_SC_PAGE_SIZE).  */

+static unsigned long page_size;

+

+/* Test parameters. */

+static size_t allocation_size;

+static size_t alignment;

+static enum {

+  with_malloc,

+  with_realloc,

+  with_aligned_alloc,

+  with_memalign,

+  with_posix_memalign,

+  with_valloc,

+  with_pvalloc,

+  with_calloc,

+  last_allocation_function = with_calloc

+} allocation_function;

+

+/* True if an allocation function uses the alignment test

+   parameter.  */

+const static bool alignment_sensitive[last_allocation_function + 1] =

+  {

+    [with_aligned_alloc] = true,

+    [with_memalign] = true,

+    [with_posix_memalign] = true,

+  };

+

+/* Combined pointer/expected alignment result of an allocation

+   function.  */

+struct allocate_result {

+  void *pointer;

+  size_t alignment;

+};

+

+/* Call the allocation function specified by allocation_function, with

+   allocation_size and alignment (if applicable) as arguments.  No

+   alignment check.  */

+static struct allocate_result

+allocate_1 (void)

+{

+  switch (allocation_function)

+    {

+    case with_malloc:

+      return (struct allocate_result)

+        {malloc (allocation_size), __alignof__ (libc_max_align_t)};

+    case with_realloc:

+      {

+        void *p = realloc (NULL, 16);

+        void *q;

+        if (p == NULL)

+          q = NULL;

+        else

+          {

+            q = realloc (p, allocation_size);

+            if (q == NULL)

+              free (p);

+          }

+        return (struct allocate_result) {q, __alignof__ (libc_max_align_t)};

+      }

+    case with_aligned_alloc:

+      {

+        void *p = aligned_alloc (alignment, allocation_size);

+        return (struct allocate_result) {p, alignment};

+      }

+    case with_memalign:

+      {

+        void *p = memalign (alignment, allocation_size);

+        return (struct allocate_result) {p, alignment};

+      }

+    case with_posix_memalign:

+      {

+        void *p;

+        if (posix_memalign (&p, alignment, allocation_size))

+          {

+            if (errno == ENOMEM)

+              p = NULL;

+            else

+              {

+                printf ("error: posix_memalign (p, %zu, %zu): %m\n",

+                        alignment, allocation_size);

+                abort ();

+              }

+          }

+        return (struct allocate_result) {p, alignment};

+      }

+    case with_valloc:

+      {

+        void *p = valloc (allocation_size);

+        return (struct allocate_result) {p, page_size};

+      }

+    case with_pvalloc:

+      {

+        void *p = pvalloc (allocation_size);

+        return (struct allocate_result) {p, page_size};

+      }

+    case with_calloc:

+      {

+        char *p = allocate_zeroed (1, allocation_size);

+        /* Check for non-zero bytes.  */

+        if (p != NULL)

+          for (size_t i = 0; i < allocation_size; ++i)

+            if (p[i] != 0)

+              {

+                printf ("error: non-zero byte at offset %zu\n", i);

+                abort ();

+              }

+        return (struct allocate_result) {p, __alignof__ (libc_max_align_t)};

+      }

+    }

+  abort ();

+}

+

+/* Call allocate_1 and perform the alignment check on the result.  */

+static void *

+allocate (void)

+{

+  struct allocate_result r = allocate_1 ();

+#if __powerpc__ == 1 && __powerpc64__ == 0

+  /* Sourceware bug 6527 on 32-bit POWER.

+     Ignore 16-byte alignment requirement when using malloc, realloc, or

+     calloc, since these functions are known not to provide enough

+     alignment.  */

+  if ((((uintptr_t) r.pointer) & (r.alignment - 1)) != 0

+      && !(r.alignment == 16

+	   && (allocation_function == with_malloc

+	       || allocation_function == with_realloc

+	       || allocation_function == with_calloc)))

+#else

+  if ((((uintptr_t) r.pointer) & (r.alignment - 1)) != 0)

+#endif

+    {

+      printf ("error: allocation function %d, size %zu not aligned to %zu\n",

+              (int) allocation_function, allocation_size, r.alignment);

+      abort ();

+    }

+  return r.pointer;

+}

+

+/* Barriers to synchronize thread creation and termination.  */

+static pthread_barrier_t start_barrier;

+static pthread_barrier_t end_barrier;

+

+/* Thread function which performs the allocation test.  Called by

+   pthread_create and from the main thread.  */

+static void *

+allocate_thread (void *closure)

+{

+  /* Wait for the creation of all threads.  */

+  {

+    int ret = pthread_barrier_wait (&start_barrier);

+    if (ret != 0 && ret != PTHREAD_BARRIER_SERIAL_THREAD)

+      {

+        errno = ret;

+        printf ("error: pthread_barrier_wait: %m\n");

+        abort ();

+      }

+  }

+

+  /* Allocate until we run out of memory, creating a single-linked

+     list.  */

+  struct list {

+    struct list *next;

+  };

+  struct list *head = NULL;

+  while (true)

+    {

+      struct list *e = allocate ();

+      if (e == NULL)

+        break;

+

+      e->next = head;

+      head = e;

+    }

+

+  /* Wait for the allocation of all available memory.  */

+  {

+    int ret = pthread_barrier_wait (&end_barrier);

+    if (ret != 0 && ret != PTHREAD_BARRIER_SERIAL_THREAD)

+      {

+        errno = ret;

+        printf ("error: pthread_barrier_wait: %m\n");

+        abort ();

+      }

+  }

+

+  /* Free the allocated memory.  */

+  while (head != NULL)

+    {

+      struct list *next = head->next;

+      free (head);

+      head = next;

+    }

+

+  return NULL;

+}

+

+/* Number of threads (plus the main thread.  */

+enum { thread_count = 8 };

+

+/* Thread attribute to request creation of threads with a non-default

+   stack size which is rather small.  This avoids interfering with the

+   configured address space limit.  */

+static pthread_attr_t small_stack;

+

+/* Runs one test in multiple threads, all in a subprocess so that

+   subsequent tests do not interfere with each other.  */

+static void

+run_one (void)

+{

+  /* Isolate the tests in a subprocess, so that we can start over

+     from scratch.  */

+  pid_t pid = fork ();

+  if (pid == 0)

+    {

+      /* In the child process.  Create the allocation threads.  */

+      pthread_t threads[thread_count];

+

+      for (unsigned i = 0; i < thread_count; ++i)

+        {

+          int ret = pthread_create (threads + i, &small_stack, allocate_thread, NULL);

+          if (ret != 0)

+            {

+              errno = ret;

+              printf ("error: pthread_create: %m\n");

+              abort ();

+            }

+        }

+

+      /* Also run the test on the main thread.  */

+      allocate_thread (NULL);

+

+      for (unsigned i = 0; i < thread_count; ++i)

+        {

+          int ret = pthread_join (threads[i], NULL);

+          if (ret != 0)

+            {

+              errno = ret;

+              printf ("error: pthread_join: %m\n");

+              abort ();

+            }

+        }

+      _exit (0);

+    }

+  else if (pid < 0)

+    {

+      printf ("error: fork: %m\n");

+      abort ();

+    }

+

+  /* In the parent process.  Wait for the child process to exit.  */

+  int status;

+  if (waitpid (pid, &status, 0) < 0)

+    {

+      printf ("error: waitpid: %m\n");

+      abort ();

+    }

+  if (status != 0)

+    {

+      printf ("error: exit status %d from child process\n", status);

+      exit (1);

+    }

+}

+

+/* Run all applicable allocation functions for the current test

+   parameters.  */

+static void

+run_allocation_functions (void)

+{

+  for (int af = 0; af <= last_allocation_function; ++af)

+    {

+      /* Run alignment-sensitive functions for non-default

+         alignments.  */

+      if (alignment_sensitive[af] != (alignment != 0))

+        continue;

+      allocation_function = af;

+      run_one ();

+    }

+}

+

+int

+do_test (void)

+{

+  /* Limit the number of malloc arenas.  We use a very low number so

+     that despute the address space limit configured below, all

+     requested arenas a can be created.  */

+  if (mallopt (M_ARENA_MAX, 2) == 0)

+    {

+      printf ("error: mallopt (M_ARENA_MAX) failed\n");

+      return 1;

+    }

+

+  /* Determine the page size.  */

+  {

+    long ret = sysconf (_SC_PAGE_SIZE);

+    if (ret < 0)

+      {

+        printf ("error: sysconf (_SC_PAGE_SIZE): %m\n");

+        return 1;

+      }

+    page_size = ret;

+  }

+

+  /* Limit the size of the process, so that memory allocation in

+     allocate_thread will eventually fail, without impacting the

+     entire system.  */

+  {

+    struct rlimit limit;

+    if (getrlimit (RLIMIT_AS, &limit) != 0)

+      {

+        printf ("getrlimit (RLIMIT_AS) failed: %m\n");

+        return 1;

+      }

+    long target = 200 * 1024 * 1024;

+    if (limit.rlim_cur == RLIM_INFINITY || limit.rlim_cur > target)

+      {

+        limit.rlim_cur = target;

+        if (setrlimit (RLIMIT_AS, &limit) != 0)

+          {

+            printf ("setrlimit (RLIMIT_AS) failed: %m\n");

+            return 1;

+          }

+      }

+  }

+

+  /* Initialize thread attribute with a reduced stack size.  */

+  {

+    int ret = pthread_attr_init (&small_stack);

+    if (ret != 0)

+      {

+        errno = ret;

+        printf ("error: pthread_attr_init: %m\n");

+        abort ();

+      }

+    unsigned long stack_size = ((256 * 1024) / page_size) * page_size;

+    if (stack_size < 4 * page_size)

+      stack_size = 8 * page_size;

+    ret = pthread_attr_setstacksize (&small_stack, stack_size);

+    if (ret != 0)

+      {

+        errno = ret;

+        printf ("error: pthread_attr_setstacksize: %m\n");

+        abort ();

+      }

+  }

+

+  /* Initialize the barriers.  We run thread_count threads, plus 1 for

+     the main thread.  */

+  {

+    int ret = pthread_barrier_init (&start_barrier, NULL, thread_count + 1);

+    if (ret != 0)

+      {

+        errno = ret;

+        printf ("error: pthread_barrier_init: %m\n");

+        abort ();

+      }

+

+    ret = pthread_barrier_init (&end_barrier, NULL, thread_count + 1);

+    if (ret != 0)

+      {

+        errno = ret;

+        printf ("error: pthread_barrier_init: %m\n");

+        abort ();

+      }

+  }

+

+  allocation_size = 144;

+  run_allocation_functions ();

+  allocation_size = page_size;

+  run_allocation_functions ();

+

+  alignment = 128;

+  allocation_size = 512;

+  run_allocation_functions ();

+

+  allocation_size = page_size;

+  run_allocation_functions ();

+

+  allocation_size = 17 * page_size;

+  run_allocation_functions ();

+

+  /* Deallocation the barriers and the thread attribute.  */

+  {

+    int ret = pthread_barrier_destroy (&end_barrier);

+    if (ret != 0)

+      {

+        errno = ret;

+        printf ("error: pthread_barrier_destroy: %m\n");

+        return 1;

+      }

+    ret = pthread_barrier_destroy (&start_barrier);

+    if (ret != 0)

+      {

+        errno = ret;

+        printf ("error: pthread_barrier_destroy: %m\n");

+        return 1;

+      }

+    ret = pthread_attr_destroy (&small_stack);

+    if (ret != 0)

+      {

+        errno = ret;

+        printf ("error: pthread_attr_destroy: %m\n");

+        return 1;

+      }

+  }

+

+  return 0;

+}

+

+/* The repeated allocations take some time on slow machines.  */

+#define TIMEOUT 20

+

+/* No malloc perturbation should be used. We are testing that

+   default 0 perturbation values work.  */

+#define MALLOC_PERTURB 0

+

+#define TEST_FUNCTION do_test ()

+#include "../test-skeleton.c"

Index: glibc-2.17-c758a686/test-skeleton.c

===================================================================

--- glibc-2.17-c758a686.orig/test-skeleton.c

+++ glibc-2.17-c758a686/test-skeleton.c

@@ -233,7 +233,10 @@ main (int argc, char *argv[])

   pid_t termpid;

   /* Make uses of freed and uninitialized memory known.  */

-  mallopt (M_PERTURB, 42);

+#ifndef MALLOC_PERTURB

+# define MALLOC_PERTURB 42

+#endif

+  mallopt (M_PERTURB, MALLOC_PERTURB);

 #ifdef STDOUT_UNBUFFERED

   setbuf (stdout, NULL);