Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

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

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

include/linux/kernel.h

+3 −0
Original line number Diff line number Diff line
@@ -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);

kernel/extable.c

+16 −0
Original line number Diff line number Diff line
@@ -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;

}

kernel/notifier.c

+1 −9
Original line number Diff line number Diff line
@@ -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;

lib/vsprintf.c

+1 −1
Original line number Diff line number Diff line
@@ -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;