syslinux/syslinux-4.04-cache_fix.patch

commit 0a0e0e41cad93cd16c323cf16f40264a21eedd6c
Author: H. Peter Anvin <hpa@zytor.com>
Date:   Thu Jul 19 07:29:55 2012 -0700

    Correct initialization of the cache doubly-linked list
    
    The initialization of the cache doubly-linked list had
    head->next->prev instead of head->prev->next; this entry is supposed
    to initialize the ->next entry of the last entry in the list (which
    points back to the head node.)
    
    For clarity, consistently use "head" to refer to the head node; the
    mixing of "head" and "dev->cache_head" needlessly obfuscated the code.
    
    The wild pointer reference caused crashes on some systems.
    
    Reported-by: Jan Safrata <jsafrata@centrum.cz>
    Signed-off-by: H. Peter Anvin <hpa@zytor.com>

Index: syslinux-4.04/core/fs/cache.c
===================================================================
--- syslinux-4.04.orig/core/fs/cache.c
+++ syslinux-4.04/core/fs/cache.c
@@ -37,10 +37,10 @@ void cache_init(struct device *dev, int
 
     dev->cache_head = head = (struct cache *)
 	(data + (dev->cache_entries << block_size_shift));
-    cache = dev->cache_head + 1; /* First cache descriptor */
+    cache = head + 1;		/* First cache descriptor */
 
     head->prev  = &cache[dev->cache_entries-1];
-    head->next->prev = dev->cache_head;
+    head->prev->next = head;
     head->block = -1;
     head->data  = NULL;