Commit ab7476cf authored by Arjan van de Ven's avatar Arjan van de Ven Committed by Ingo Molnar

debug: add notifier chain debugging, v2

- unbreak ia64 (and powerpc) where function pointers dont
  point at code but at data (reported by Tony Luck)

[ mingo@elte.hu: various cleanups ]
Signed-off-by: default avatarArjan van de Ven <arjan@linux.intel.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent fb822db4
......@@ -187,6 +187,9 @@ extern unsigned long long memparse(char *ptr, char **retptr);
extern int core_kernel_text(unsigned long addr);
extern int __kernel_text_address(unsigned long addr);
extern int kernel_text_address(unsigned long addr);
extern int func_ptr_is_kernel_text(void *ptr);
extern void *dereference_function_descriptor(void *ptr);
struct pid;
extern struct pid *session_of_pgrp(struct pid *pgrp);
......
......@@ -66,3 +66,19 @@ int kernel_text_address(unsigned long addr)
return 1;
return module_text_address(addr) != NULL;
}
/*
* On some architectures (PPC64, IA64) function pointers
* are actually only tokens to some data that then holds the
* real function address. As a result, to find if a function
* pointer is part of the kernel text, we need to do some
* special dereferencing first.
*/
int func_ptr_is_kernel_text(void *ptr)
{
unsigned long addr;
addr = (unsigned long) dereference_function_descriptor(ptr);
if (core_kernel_text(addr))
return 1;
return module_text_address(addr) != NULL;
}
......@@ -21,10 +21,6 @@ BLOCKING_NOTIFIER_HEAD(reboot_notifier_list);
static int notifier_chain_register(struct notifier_block **nl,
struct notifier_block *n)
{
if (!kernel_text_address((unsigned long)n->notifier_call)) {
WARN(1, "Invalid notifier registered!");
return 0;
}
while ((*nl) != NULL) {
if (n->priority > (*nl)->priority)
break;
......@@ -38,10 +34,6 @@ static int notifier_chain_register(struct notifier_block **nl,
static int notifier_chain_cond_register(struct notifier_block **nl,
struct notifier_block *n)
{
if (!kernel_text_address((unsigned long)n->notifier_call)) {
WARN(1, "Invalid notifier registered!");
return 0;
}
while ((*nl) != NULL) {
if ((*nl) == n)
return 0;
......@@ -92,7 +84,7 @@ static int __kprobes notifier_call_chain(struct notifier_block **nl,
next_nb = rcu_dereference(nb->next);
#ifdef CONFIG_DEBUG_NOTIFIERS
if (!kernel_text_address((unsigned long)nb->notifier_call)) {
if (unlikely(!func_ptr_is_kernel_text(nb->notifier_call))) {
WARN(1, "Invalid notifier called!");
nb = next_nb;
continue;
......
......@@ -513,7 +513,7 @@ static char *string(char *buf, char *end, char *s, int field_width, int precisio
return buf;
}
static inline void *dereference_function_descriptor(void *ptr)
void *dereference_function_descriptor(void *ptr)
{
#if defined(CONFIG_IA64) || defined(CONFIG_PPC64)
void *p;
......
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