[Commits] r24956 - in /fsf/glibc-2_16-branch/libc: ChangeLog NEWS malloc/malloc.c

[eglibc@xxxxxxxxxx]

Author: eglibc
Date: Sun Jan  5 00:10:09 2014
New Revision: 24956

Log:
Import glibc-2.16 for 2014-01-05

Modified:
    fsf/glibc-2_16-branch/libc/ChangeLog
    fsf/glibc-2_16-branch/libc/NEWS
    fsf/glibc-2_16-branch/libc/malloc/malloc.c

Modified: fsf/glibc-2_16-branch/libc/ChangeLog
==============================================================================
--- fsf/glibc-2_16-branch/libc/ChangeLog (original)
+++ fsf/glibc-2_16-branch/libc/ChangeLog Sun Jan  5 00:10:09 2014
@@ -1,3 +1,10 @@
+2014-01-04  Maxim Kuvyrkov  <maxim@xxxxxxxxxxxxxx>
+	    OndÃÂej BÃÂlka  <neleai@xxxxxxxxx>
+
+	[BZ #15073]
+	* malloc/malloc.c (_int_free): Perform sanity check only if we
+        have_lock.
+
 2012-11-20  Thomas Schwinge  <thomas@xxxxxxxxxxxxxxxx>
 
 	* sysdeps/sh/dl-machine.h (ELF_MACHINE_RUNTIME_FIXUP_PARAMS): New

Modified: fsf/glibc-2_16-branch/libc/NEWS
==============================================================================
--- fsf/glibc-2_16-branch/libc/NEWS (original)
+++ fsf/glibc-2_16-branch/libc/NEWS Sun Jan  5 00:10:09 2014
@@ -9,7 +9,7 @@
 
 * The following bugs are resolved with this release:
 
-  6530, 14195, 14459, 14476, 14562, 14621, 14648, 14756, 14831
+  6530, 14195, 14459, 14476, 14562, 14621, 14648, 14756, 14831, 15073
 
 Version 2.16
 

Modified: fsf/glibc-2_16-branch/libc/malloc/malloc.c
==============================================================================
--- fsf/glibc-2_16-branch/libc/malloc/malloc.c (original)
+++ fsf/glibc-2_16-branch/libc/malloc/malloc.c Sun Jan  5 00:10:09 2014
@@ -3868,25 +3868,29 @@
     unsigned int idx = fastbin_index(size);
     fb = &fastbin (av, idx);
 
-    mchunkptr fd;
-    mchunkptr old = *fb;
+    /* Atomically link P to its fastbin: P->FD = *FB; *FB = P;  */
+    mchunkptr old = *fb, old2;
     unsigned int old_idx = ~0u;
     do
       {
-	/* Another simple check: make sure the top of the bin is not the
-	   record we are going to add (i.e., double free).  */
+	/* Check that the top of the bin is not the record we are going to add
+	   (i.e., double free).  */
 	if (__builtin_expect (old == p, 0))
 	  {
 	    errstr = "double free or corruption (fasttop)";
 	    goto errout;
 	  }
-	if (old != NULL)
+	/* Check that size of fastbin chunk at the top is the same as
+	   size of the chunk that we are adding.  We can dereference OLD
+	   only if we have the lock, otherwise it might have already been
+	   deallocated.  See use of OLD_IDX below for the actual check.  */
+	if (have_lock && old != NULL)
 	  old_idx = fastbin_index(chunksize(old));
-	p->fd = fd = old;
+	p->fd = old2 = old;
       }
-    while ((old = catomic_compare_and_exchange_val_rel (fb, p, fd)) != fd);
-
-    if (fd != NULL && __builtin_expect (old_idx != idx, 0))
+    while ((old = catomic_compare_and_exchange_val_rel (fb, p, old2)) != old2);
+
+    if (have_lock && old != NULL && __builtin_expect (old_idx != idx, 0))
       {
 	errstr = "invalid fastbin entry (free)";
 	goto errout;

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