From 281297db9f4544c48a811442fce691dc91ca11a3 Mon Sep 17 00:00:00 2001
From: Nicholas Nethercote <njn@valgrind.org>
Date: Wed, 24 Aug 2005 22:38:00 +0000
Subject: [PATCH] Fix a problem I introduced in r4208 when reducing the space
 used by heap blocks.  The minimum size for redzones is now sizeof(void*), but
 I forgot to ensure this.  Massif was asking for 0 byte redzones, and this was
 screwing things up on 64-bit platforms, and Massif was dying very quickly. 
 This should fix bugs #111090 and #111285.

The fact that Massif was this badly broken but there were only 2 bug reports
indicates that not many people are using it, at least not on AMD64.

I also added a regtest that does some basic malloc/realloc/free testing
for Massif, which would have caught this problem.


git-svn-id: svn://svn.valgrind.org/valgrind/trunk@4492
---
 coregrind/m_mallocfree.c             | 11 +++++++---
 massif/tests/Makefile.am             |  6 ++++++
 massif/tests/basic_malloc.c          | 31 ++++++++++++++++++++++++++++
 massif/tests/basic_malloc.stderr.exp |  6 ++++++
 massif/tests/basic_malloc.vgtest     |  2 ++
 5 files changed, 53 insertions(+), 3 deletions(-)
 create mode 100644 massif/tests/basic_malloc.c
 create mode 100644 massif/tests/basic_malloc.stderr.exp
 create mode 100644 massif/tests/basic_malloc.vgtest

diff --git a/coregrind/m_mallocfree.c b/coregrind/m_mallocfree.c
index 9a4a6dd23e..0bd0136599 100644
--- a/coregrind/m_mallocfree.c
+++ b/coregrind/m_mallocfree.c
@@ -59,9 +59,9 @@ typedef UChar UByte;
 /* Layout of an in-use block:
 
       this block total szB     (sizeof(SizeT) bytes)
-      red zone bytes           (depends on Arena.rz_szB, but > sizeof(void*))
+      red zone bytes           (depends on Arena.rz_szB, but >= sizeof(void*))
       (payload bytes)
-      red zone bytes           (depends on Arena.rz_szB, but > sizeof(void*))
+      red zone bytes           (depends on Arena.rz_szB, but >= sizeof(void*))
       this block total szB     (sizeof(SizeT) bytes)
 
    Layout of a block on the free list:
@@ -375,7 +375,12 @@ void arena_init ( ArenaId aid, Char* name, SizeT rz_szB, SizeT min_sblock_szB )
    SizeT i;
    Arena* a = arenaId_to_ArenaP(aid);
    
-   vg_assert(rz_szB < 128);      // ensure reasonable size
+   // Ensure redzones are a reasonable size.  They must always be at least
+   // the size of a pointer, for holding the prev/next pointer (see the layout
+   // details at the top of this file).
+   vg_assert(rz_szB < 128);
+   if (rz_szB < sizeof(void*)) rz_szB = sizeof(void*);
+   
    vg_assert((min_sblock_szB % VKI_PAGE_SIZE) == 0);
    a->name      = name;
    a->clientmem = ( VG_AR_CLIENT == aid ? True : False );
diff --git a/massif/tests/Makefile.am b/massif/tests/Makefile.am
index 0616d78024..025acc0dd2 100644
--- a/massif/tests/Makefile.am
+++ b/massif/tests/Makefile.am
@@ -1,7 +1,13 @@
 noinst_SCRIPTS = filter_stderr
 
 EXTRA_DIST = $(noinst_SCRIPTS) \
+        basic_malloc.stderr.exp basic_malloc.vgtest \
         toobig-allocs.stderr.exp toobig-allocs.vgtest \
         true_html.stderr.exp true_html.vgtest \
         true_text.stderr.exp true_text.vgtest
 
+AM_CFLAGS   = $(WERROR) -Winline -Wall -Wshadow -g 
+
+check_PROGRAMS = \
+	basic_malloc
+
diff --git a/massif/tests/basic_malloc.c b/massif/tests/basic_malloc.c
new file mode 100644
index 0000000000..7cb452c0a9
--- /dev/null
+++ b/massif/tests/basic_malloc.c
@@ -0,0 +1,31 @@
+// In 3.0.0, Massif was badly broken on 64-bit platforms because it asked
+// zero-sized redzones, and the allocator was forgetting to round the size
+// up to sizeof(void*), which is the minimum.  This caused bugs #111090 and
+// #111285.  This test is just a gentle allocation exercise which was
+// failing.
+
+#include <stdlib.h>
+#include <stdio.h>
+
+#define NN  100
+
+int main(void)
+{ 
+   int i;
+   char* a[NN];
+
+   for (i = i; i < NN; i++) {
+      a[i] = malloc(i);
+   }
+   
+   for (i = i; i < NN; i++) {
+      a[i] = realloc(a[i], NN - i);
+   }
+   
+   for (i = i; i < NN; i++) {
+      free(a[i]);
+   }
+   
+   return 0;
+}
+
diff --git a/massif/tests/basic_malloc.stderr.exp b/massif/tests/basic_malloc.stderr.exp
new file mode 100644
index 0000000000..c3baf21931
--- /dev/null
+++ b/massif/tests/basic_malloc.stderr.exp
@@ -0,0 +1,6 @@
+
+
+Total spacetime:   
+heap:              
+heap admin:        
+stack(s):          
diff --git a/massif/tests/basic_malloc.vgtest b/massif/tests/basic_malloc.vgtest
new file mode 100644
index 0000000000..c63d4817d0
--- /dev/null
+++ b/massif/tests/basic_malloc.vgtest
@@ -0,0 +1,2 @@
+prog: basic_malloc
+cleanup: rm massif.*.*
-- 
2.47.3