[PATCH] x86_64: Fix overflow in NUMA hash function setup

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 26 insertions, 24 deletions

diff --git a/arch/x86_64/mm/numa.c b/arch/x86_64/mm/numa.c
index ac61c186eb02..70cb2904a90f 100644
--- a/arch/x86_64/mm/numa.c
+++ b/arch/x86_64/mm/numa.c
@@ -36,34 +36,36 @@ int numa_off __initdata;
 int __init compute_hash_shift(struct node *nodes, int numnodes)
 {
         int i; 
-        int shift = 24;
-        u64 addr;
+        int shift = 20;
+        unsigned long addr,maxend=0;
         
-        /* When in doubt use brute force. */
-        while (shift < 48) { 
-                memset(memnodemap,0xff,sizeof(*memnodemap) * NODEMAPSIZE); 
-                for (i = 0; i < numnodes; i++) {
-                        if (nodes[i].start == nodes[i].end) 
-                                continue;
-                        for (addr = nodes[i].start; 
-                             addr < nodes[i].end; 
-                             addr += (1UL << shift)) {
-                                if (memnodemap[addr >> shift] != 0xff && 
-                                    memnodemap[addr >> shift] != i) { 
-                                        printk(KERN_INFO 
-                                            "node %d shift %d addr %Lx conflict %d\n", 
-                                               i, shift, addr, memnodemap[addr>>shift]);
-                                        goto next; 
-                                } 
-                                memnodemap[addr >> shift] = i; 
+        for (i = 0; i < numnodes; i++)
+                if ((nodes[i].start != nodes[i].end) && (nodes[i].end > maxend))
+                                maxend = nodes[i].end;
+
+        while ((1UL << shift) <  (maxend / NODEMAPSIZE))
+                shift++;
+
+        printk (KERN_DEBUG"Using %d for the hash shift. Max adder is %lx \n",
+                        shift,maxend);
+        memset(memnodemap,0xff,sizeof(*memnodemap) * NODEMAPSIZE);
+        for (i = 0; i < numnodes; i++) {
+                if (nodes[i].start == nodes[i].end)
+                        continue;
+                for (addr = nodes[i].start;
+                     addr < nodes[i].end;
+                     addr += (1UL << shift)) {
+                        if (memnodemap[addr >> shift] != 0xff) {
+                                printk(KERN_INFO
+        "Your memory is not aligned you need to rebuild your kernel "
+        "with a bigger NODEMAPSIZE shift=%d adder=%lu\n",
+                                        shift,addr);
+                                return -1;
                         } 
+                        memnodemap[addr >> shift] = i;
                 } 
-                return shift; 
-        next:
-                shift++; 
         } 
-        memset(memnodemap,0,sizeof(*memnodemap) * NODEMAPSIZE); 
-        return -1; 
+        return shift;
 }
 
 #ifdef CONFIG_SPARSEMEM