kprobes: remove dependency on CONFIG_MODULES

kprobes depended on CONFIG_MODULES because it has to allocate memory for
code.

Since code allocations are now implemented with execmem, kprobes can be
enabled in non-modular kernels.

Add #ifdef CONFIG_MODULE guards for the code dealing with kprobes inside
modules, make CONFIG_KPROBES select CONFIG_EXECMEM and drop the
dependency of CONFIG_KPROBES on CONFIG_MODULES.

Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
[mcgrof: rebase in light of NEED_TASKS_RCU ]
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
This commit is contained in:
Mike Rapoport (IBM) 2024-05-05 19:06:27 +03:00 committed by Luis Chamberlain
parent 0a956d52e6
commit 7582b7be16
4 changed files with 63 additions and 23 deletions

View File

@ -60,9 +60,9 @@ config GENERIC_ENTRY
config KPROBES
bool "Kprobes"
depends on MODULES
depends on HAVE_KPROBES
select KALLSYMS
select EXECMEM
select NEED_TASKS_RCU
help
Kprobes allows you to trap at almost any kernel address and

View File

@ -605,6 +605,11 @@ static inline bool module_is_live(struct module *mod)
return mod->state != MODULE_STATE_GOING;
}
static inline bool module_is_coming(struct module *mod)
{
return mod->state == MODULE_STATE_COMING;
}
struct module *__module_text_address(unsigned long addr);
struct module *__module_address(unsigned long addr);
bool is_module_address(unsigned long addr);
@ -857,6 +862,10 @@ void *dereference_module_function_descriptor(struct module *mod, void *ptr)
return ptr;
}
static inline bool module_is_coming(struct module *mod)
{
return false;
}
#endif /* CONFIG_MODULES */
#ifdef CONFIG_SYSFS

View File

@ -1588,7 +1588,7 @@ static int check_kprobe_address_safe(struct kprobe *p,
}
/* Get module refcount and reject __init functions for loaded modules. */
if (*probed_mod) {
if (IS_ENABLED(CONFIG_MODULES) && *probed_mod) {
/*
* We must hold a refcount of the probed module while updating
* its code to prohibit unexpected unloading.
@ -1603,12 +1603,13 @@ static int check_kprobe_address_safe(struct kprobe *p,
* kprobes in there.
*/
if (within_module_init((unsigned long)p->addr, *probed_mod) &&
(*probed_mod)->state != MODULE_STATE_COMING) {
!module_is_coming(*probed_mod)) {
module_put(*probed_mod);
*probed_mod = NULL;
ret = -ENOENT;
}
}
out:
preempt_enable();
jump_label_unlock();
@ -2488,24 +2489,6 @@ int kprobe_add_area_blacklist(unsigned long start, unsigned long end)
return 0;
}
/* Remove all symbols in given area from kprobe blacklist */
static void kprobe_remove_area_blacklist(unsigned long start, unsigned long end)
{
struct kprobe_blacklist_entry *ent, *n;
list_for_each_entry_safe(ent, n, &kprobe_blacklist, list) {
if (ent->start_addr < start || ent->start_addr >= end)
continue;
list_del(&ent->list);
kfree(ent);
}
}
static void kprobe_remove_ksym_blacklist(unsigned long entry)
{
kprobe_remove_area_blacklist(entry, entry + 1);
}
int __weak arch_kprobe_get_kallsym(unsigned int *symnum, unsigned long *value,
char *type, char *sym)
{
@ -2570,6 +2553,25 @@ static int __init populate_kprobe_blacklist(unsigned long *start,
return ret ? : arch_populate_kprobe_blacklist();
}
#ifdef CONFIG_MODULES
/* Remove all symbols in given area from kprobe blacklist */
static void kprobe_remove_area_blacklist(unsigned long start, unsigned long end)
{
struct kprobe_blacklist_entry *ent, *n;
list_for_each_entry_safe(ent, n, &kprobe_blacklist, list) {
if (ent->start_addr < start || ent->start_addr >= end)
continue;
list_del(&ent->list);
kfree(ent);
}
}
static void kprobe_remove_ksym_blacklist(unsigned long entry)
{
kprobe_remove_area_blacklist(entry, entry + 1);
}
static void add_module_kprobe_blacklist(struct module *mod)
{
unsigned long start, end;
@ -2672,6 +2674,17 @@ static struct notifier_block kprobe_module_nb = {
.priority = 0
};
static int kprobe_register_module_notifier(void)
{
return register_module_notifier(&kprobe_module_nb);
}
#else
static int kprobe_register_module_notifier(void)
{
return 0;
}
#endif /* CONFIG_MODULES */
void kprobe_free_init_mem(void)
{
void *start = (void *)(&__init_begin);
@ -2731,7 +2744,7 @@ static int __init init_kprobes(void)
if (!err)
err = register_die_notifier(&kprobe_exceptions_nb);
if (!err)
err = register_module_notifier(&kprobe_module_nb);
err = kprobe_register_module_notifier();
kprobes_initialized = (err == 0);
kprobe_sysctls_init();

View File

@ -111,6 +111,7 @@ static nokprobe_inline bool trace_kprobe_within_module(struct trace_kprobe *tk,
return strncmp(module_name(mod), name, len) == 0 && name[len] == ':';
}
#ifdef CONFIG_MODULES
static nokprobe_inline bool trace_kprobe_module_exist(struct trace_kprobe *tk)
{
char *p;
@ -129,6 +130,12 @@ static nokprobe_inline bool trace_kprobe_module_exist(struct trace_kprobe *tk)
return ret;
}
#else
static inline bool trace_kprobe_module_exist(struct trace_kprobe *tk)
{
return false;
}
#endif
static bool trace_kprobe_is_busy(struct dyn_event *ev)
{
@ -670,6 +677,7 @@ end:
return ret;
}
#ifdef CONFIG_MODULES
/* Module notifier call back, checking event on the module */
static int trace_kprobe_module_callback(struct notifier_block *nb,
unsigned long val, void *data)
@ -704,6 +712,16 @@ static struct notifier_block trace_kprobe_module_nb = {
.notifier_call = trace_kprobe_module_callback,
.priority = 1 /* Invoked after kprobe module callback */
};
static int trace_kprobe_register_module_notifier(void)
{
return register_module_notifier(&trace_kprobe_module_nb);
}
#else
static int trace_kprobe_register_module_notifier(void)
{
return 0;
}
#endif /* CONFIG_MODULES */
static int count_symbols(void *data, unsigned long unused)
{
@ -1933,7 +1951,7 @@ static __init int init_kprobe_trace_early(void)
if (ret)
return ret;
if (register_module_notifier(&trace_kprobe_module_nb))
if (trace_kprobe_register_module_notifier())
return -EINVAL;
return 0;