--- drivers/oprofile/cpu_buffer.c.orig	2007-10-03 21:36:08.000000000 +0200
+++ drivers/oprofile/cpu_buffer.c	2007-10-11 12:41:57.000000000 +0200
@@ -241,7 +241,7 @@
 void oprofile_add_sample(struct pt_regs * const regs, unsigned long event)
 {
 	int is_kernel = !user_mode(regs);
-	unsigned long pc = profile_pc(regs);
+	unsigned long pc = instruction_pointer(regs);
 
 	oprofile_add_ext_sample(pc, regs, event, is_kernel);
 }
--- drivers/oprofile/buffer_sync.c.orig	2007-10-04 10:15:27.000000000 +0200
+++ drivers/oprofile/buffer_sync.c	2007-10-11 12:49:22.000000000 +0200
@@ -530,11 +530,30 @@
 				/* userspace context switch */
 				new = (struct task_struct *)s->event;
 
-				release_mm(oldmm);
-				mm = take_tasks_mm(new);
-				if (mm != oldmm)
-					cookie = get_exec_dcookie(mm);
-				add_user_ctx_switch(new, cookie);
+				/* Ugly, let says task pointer can't be
+				   in the last page nor in the first page */
+				if (s->event + 0x1000 > 0x2000) {
+					release_mm(oldmm);
+					mm = take_tasks_mm(new);
+					if (mm != oldmm)
+						cookie = get_exec_dcookie(mm);
+					add_user_ctx_switch(new, cookie);
+				} else {
+					static int show_it = 0;
+					if (show_it++ < 5) {
+						printk(KERN_INFO
+						       "oprofile: Invalid "
+						       "event %lu, head %lu, "
+						       "tail %lu, eip %lu, "
+						       "available %lu, i %u "
+						       "state %d %d\n",
+						       s->event,
+						       cpu_buf->head_pos,
+						       cpu_buf->tail_pos,
+						       s->eip, available, i,
+						       state, in_kernel);
+					}
+				}
 			}
 		} else {
 			if (state >= sb_bt_start &&