[PATCH] powerpc: check Cell SPU syscall number range _before_ using it

Signed-off-by: David Woodhouse <dwmw2@infradead.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: Paul Mackerras <paulus@samba.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

arch/powerpc/platforms/cell/spu_callbacks.c

@@ -339,13 +339,13 @@ long spu_sys_callback(struct spu_syscall_block *s)
 {
 	long (*syscall)(u64 a1, u64 a2, u64 a3, u64 a4, u64 a5, u64 a6);
 
-	syscall = spu_syscall_table[s->nr_ret];
-
 	if (s->nr_ret >= ARRAY_SIZE(spu_syscall_table)) {
 		pr_debug("%s: invalid syscall #%ld", __FUNCTION__, s->nr_ret);
 		return -ENOSYS;
 	}
 
+	syscall = spu_syscall_table[s->nr_ret];
+
 #ifdef DEBUG
 	print_symbol(KERN_DEBUG "SPU-syscall %s:", (unsigned long)syscall);
 	printk("syscall%ld(%lx, %lx, %lx, %lx, %lx, %lx)\n",