linux-stable/include/linux/kprobes.h
Masami Hiramatsu 97c753e62e tracing/kprobe: Fix to support kretprobe events on unloaded modules
Fix kprobe_on_func_entry() returns error code instead of false so that
register_kretprobe() can return an appropriate error code.

append_trace_kprobe() expects the kprobe registration returns -ENOENT
when the target symbol is not found, and it checks whether the target
module is unloaded or not. If the target module doesn't exist, it
defers to probe the target symbol until the module is loaded.

However, since register_kretprobe() returns -EINVAL instead of -ENOENT
in that case, it always fail on putting the kretprobe event on unloaded
modules. e.g.

Kprobe event:
/sys/kernel/debug/tracing # echo p xfs:xfs_end_io >> kprobe_events
[   16.515574] trace_kprobe: This probe might be able to register after target module is loaded. Continue.

Kretprobe event: (p -> r)
/sys/kernel/debug/tracing # echo r xfs:xfs_end_io >> kprobe_events
sh: write error: Invalid argument
/sys/kernel/debug/tracing # cat error_log
[   41.122514] trace_kprobe: error: Failed to register probe event
  Command: r xfs:xfs_end_io
             ^

To fix this bug, change kprobe_on_func_entry() to detect symbol lookup
failure and return -ENOENT in that case. Otherwise it returns -EINVAL
or 0 (succeeded, given address is on the entry).

Link: https://lkml.kernel.org/r/161176187132.1067016.8118042342894378981.stgit@devnote2

Cc: stable@vger.kernel.org
Fixes: 59158ec4ae ("tracing/kprobes: Check the probe on unloaded module correctly")
Reported-by: Jianlin Lv <Jianlin.Lv@arm.com>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2021-01-29 15:39:48 -05:00

529 lines
14 KiB
C

/* SPDX-License-Identifier: GPL-2.0-or-later */
#ifndef _LINUX_KPROBES_H
#define _LINUX_KPROBES_H
/*
* Kernel Probes (KProbes)
* include/linux/kprobes.h
*
* Copyright (C) IBM Corporation, 2002, 2004
*
* 2002-Oct Created by Vamsi Krishna S <vamsi_krishna@in.ibm.com> Kernel
* Probes initial implementation ( includes suggestions from
* Rusty Russell).
* 2004-July Suparna Bhattacharya <suparna@in.ibm.com> added jumper probes
* interface to access function arguments.
* 2005-May Hien Nguyen <hien@us.ibm.com> and Jim Keniston
* <jkenisto@us.ibm.com> and Prasanna S Panchamukhi
* <prasanna@in.ibm.com> added function-return probes.
*/
#include <linux/compiler.h>
#include <linux/linkage.h>
#include <linux/list.h>
#include <linux/notifier.h>
#include <linux/smp.h>
#include <linux/bug.h>
#include <linux/percpu.h>
#include <linux/spinlock.h>
#include <linux/rcupdate.h>
#include <linux/mutex.h>
#include <linux/ftrace.h>
#include <linux/refcount.h>
#include <linux/freelist.h>
#include <asm/kprobes.h>
#ifdef CONFIG_KPROBES
/* kprobe_status settings */
#define KPROBE_HIT_ACTIVE 0x00000001
#define KPROBE_HIT_SS 0x00000002
#define KPROBE_REENTER 0x00000004
#define KPROBE_HIT_SSDONE 0x00000008
#else /* CONFIG_KPROBES */
#include <asm-generic/kprobes.h>
typedef int kprobe_opcode_t;
struct arch_specific_insn {
int dummy;
};
#endif /* CONFIG_KPROBES */
struct kprobe;
struct pt_regs;
struct kretprobe;
struct kretprobe_instance;
typedef int (*kprobe_pre_handler_t) (struct kprobe *, struct pt_regs *);
typedef void (*kprobe_post_handler_t) (struct kprobe *, struct pt_regs *,
unsigned long flags);
typedef int (*kprobe_fault_handler_t) (struct kprobe *, struct pt_regs *,
int trapnr);
typedef int (*kretprobe_handler_t) (struct kretprobe_instance *,
struct pt_regs *);
struct kprobe {
struct hlist_node hlist;
/* list of kprobes for multi-handler support */
struct list_head list;
/*count the number of times this probe was temporarily disarmed */
unsigned long nmissed;
/* location of the probe point */
kprobe_opcode_t *addr;
/* Allow user to indicate symbol name of the probe point */
const char *symbol_name;
/* Offset into the symbol */
unsigned int offset;
/* Called before addr is executed. */
kprobe_pre_handler_t pre_handler;
/* Called after addr is executed, unless... */
kprobe_post_handler_t post_handler;
/*
* ... called if executing addr causes a fault (eg. page fault).
* Return 1 if it handled fault, otherwise kernel will see it.
*/
kprobe_fault_handler_t fault_handler;
/* Saved opcode (which has been replaced with breakpoint) */
kprobe_opcode_t opcode;
/* copy of the original instruction */
struct arch_specific_insn ainsn;
/*
* Indicates various status flags.
* Protected by kprobe_mutex after this kprobe is registered.
*/
u32 flags;
};
/* Kprobe status flags */
#define KPROBE_FLAG_GONE 1 /* breakpoint has already gone */
#define KPROBE_FLAG_DISABLED 2 /* probe is temporarily disabled */
#define KPROBE_FLAG_OPTIMIZED 4 /*
* probe is really optimized.
* NOTE:
* this flag is only for optimized_kprobe.
*/
#define KPROBE_FLAG_FTRACE 8 /* probe is using ftrace */
/* Has this kprobe gone ? */
static inline int kprobe_gone(struct kprobe *p)
{
return p->flags & KPROBE_FLAG_GONE;
}
/* Is this kprobe disabled ? */
static inline int kprobe_disabled(struct kprobe *p)
{
return p->flags & (KPROBE_FLAG_DISABLED | KPROBE_FLAG_GONE);
}
/* Is this kprobe really running optimized path ? */
static inline int kprobe_optimized(struct kprobe *p)
{
return p->flags & KPROBE_FLAG_OPTIMIZED;
}
/* Is this kprobe uses ftrace ? */
static inline int kprobe_ftrace(struct kprobe *p)
{
return p->flags & KPROBE_FLAG_FTRACE;
}
/*
* Function-return probe -
* Note:
* User needs to provide a handler function, and initialize maxactive.
* maxactive - The maximum number of instances of the probed function that
* can be active concurrently.
* nmissed - tracks the number of times the probed function's return was
* ignored, due to maxactive being too low.
*
*/
struct kretprobe_holder {
struct kretprobe *rp;
refcount_t ref;
};
struct kretprobe {
struct kprobe kp;
kretprobe_handler_t handler;
kretprobe_handler_t entry_handler;
int maxactive;
int nmissed;
size_t data_size;
struct freelist_head freelist;
struct kretprobe_holder *rph;
};
struct kretprobe_instance {
union {
struct freelist_node freelist;
struct rcu_head rcu;
};
struct llist_node llist;
struct kretprobe_holder *rph;
kprobe_opcode_t *ret_addr;
void *fp;
char data[];
};
struct kretprobe_blackpoint {
const char *name;
void *addr;
};
struct kprobe_blacklist_entry {
struct list_head list;
unsigned long start_addr;
unsigned long end_addr;
};
#ifdef CONFIG_KPROBES
DECLARE_PER_CPU(struct kprobe *, current_kprobe);
DECLARE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
/*
* For #ifdef avoidance:
*/
static inline int kprobes_built_in(void)
{
return 1;
}
extern void kprobe_busy_begin(void);
extern void kprobe_busy_end(void);
#ifdef CONFIG_KRETPROBES
extern void arch_prepare_kretprobe(struct kretprobe_instance *ri,
struct pt_regs *regs);
extern int arch_trampoline_kprobe(struct kprobe *p);
/* If the trampoline handler called from a kprobe, use this version */
unsigned long __kretprobe_trampoline_handler(struct pt_regs *regs,
void *trampoline_address,
void *frame_pointer);
static nokprobe_inline
unsigned long kretprobe_trampoline_handler(struct pt_regs *regs,
void *trampoline_address,
void *frame_pointer)
{
unsigned long ret;
/*
* Set a dummy kprobe for avoiding kretprobe recursion.
* Since kretprobe never runs in kprobe handler, no kprobe must
* be running at this point.
*/
kprobe_busy_begin();
ret = __kretprobe_trampoline_handler(regs, trampoline_address, frame_pointer);
kprobe_busy_end();
return ret;
}
static nokprobe_inline struct kretprobe *get_kretprobe(struct kretprobe_instance *ri)
{
RCU_LOCKDEP_WARN(!rcu_read_lock_any_held(),
"Kretprobe is accessed from instance under preemptive context");
return READ_ONCE(ri->rph->rp);
}
#else /* CONFIG_KRETPROBES */
static inline void arch_prepare_kretprobe(struct kretprobe *rp,
struct pt_regs *regs)
{
}
static inline int arch_trampoline_kprobe(struct kprobe *p)
{
return 0;
}
#endif /* CONFIG_KRETPROBES */
extern struct kretprobe_blackpoint kretprobe_blacklist[];
#ifdef CONFIG_KPROBES_SANITY_TEST
extern int init_test_probes(void);
#else
static inline int init_test_probes(void)
{
return 0;
}
#endif /* CONFIG_KPROBES_SANITY_TEST */
extern int arch_prepare_kprobe(struct kprobe *p);
extern void arch_arm_kprobe(struct kprobe *p);
extern void arch_disarm_kprobe(struct kprobe *p);
extern int arch_init_kprobes(void);
extern void kprobes_inc_nmissed_count(struct kprobe *p);
extern bool arch_within_kprobe_blacklist(unsigned long addr);
extern int arch_populate_kprobe_blacklist(void);
extern bool arch_kprobe_on_func_entry(unsigned long offset);
extern int kprobe_on_func_entry(kprobe_opcode_t *addr, const char *sym, unsigned long offset);
extern bool within_kprobe_blacklist(unsigned long addr);
extern int kprobe_add_ksym_blacklist(unsigned long entry);
extern int kprobe_add_area_blacklist(unsigned long start, unsigned long end);
struct kprobe_insn_cache {
struct mutex mutex;
void *(*alloc)(void); /* allocate insn page */
void (*free)(void *); /* free insn page */
const char *sym; /* symbol for insn pages */
struct list_head pages; /* list of kprobe_insn_page */
size_t insn_size; /* size of instruction slot */
int nr_garbage;
};
#ifdef __ARCH_WANT_KPROBES_INSN_SLOT
extern kprobe_opcode_t *__get_insn_slot(struct kprobe_insn_cache *c);
extern void __free_insn_slot(struct kprobe_insn_cache *c,
kprobe_opcode_t *slot, int dirty);
/* sleep-less address checking routine */
extern bool __is_insn_slot_addr(struct kprobe_insn_cache *c,
unsigned long addr);
#define DEFINE_INSN_CACHE_OPS(__name) \
extern struct kprobe_insn_cache kprobe_##__name##_slots; \
\
static inline kprobe_opcode_t *get_##__name##_slot(void) \
{ \
return __get_insn_slot(&kprobe_##__name##_slots); \
} \
\
static inline void free_##__name##_slot(kprobe_opcode_t *slot, int dirty)\
{ \
__free_insn_slot(&kprobe_##__name##_slots, slot, dirty); \
} \
\
static inline bool is_kprobe_##__name##_slot(unsigned long addr) \
{ \
return __is_insn_slot_addr(&kprobe_##__name##_slots, addr); \
}
#define KPROBE_INSN_PAGE_SYM "kprobe_insn_page"
#define KPROBE_OPTINSN_PAGE_SYM "kprobe_optinsn_page"
int kprobe_cache_get_kallsym(struct kprobe_insn_cache *c, unsigned int *symnum,
unsigned long *value, char *type, char *sym);
#else /* __ARCH_WANT_KPROBES_INSN_SLOT */
#define DEFINE_INSN_CACHE_OPS(__name) \
static inline bool is_kprobe_##__name##_slot(unsigned long addr) \
{ \
return 0; \
}
#endif
DEFINE_INSN_CACHE_OPS(insn);
#ifdef CONFIG_OPTPROBES
/*
* Internal structure for direct jump optimized probe
*/
struct optimized_kprobe {
struct kprobe kp;
struct list_head list; /* list for optimizing queue */
struct arch_optimized_insn optinsn;
};
/* Architecture dependent functions for direct jump optimization */
extern int arch_prepared_optinsn(struct arch_optimized_insn *optinsn);
extern int arch_check_optimized_kprobe(struct optimized_kprobe *op);
extern int arch_prepare_optimized_kprobe(struct optimized_kprobe *op,
struct kprobe *orig);
extern void arch_remove_optimized_kprobe(struct optimized_kprobe *op);
extern void arch_optimize_kprobes(struct list_head *oplist);
extern void arch_unoptimize_kprobes(struct list_head *oplist,
struct list_head *done_list);
extern void arch_unoptimize_kprobe(struct optimized_kprobe *op);
extern int arch_within_optimized_kprobe(struct optimized_kprobe *op,
unsigned long addr);
extern void opt_pre_handler(struct kprobe *p, struct pt_regs *regs);
DEFINE_INSN_CACHE_OPS(optinsn);
#ifdef CONFIG_SYSCTL
extern int sysctl_kprobes_optimization;
extern int proc_kprobes_optimization_handler(struct ctl_table *table,
int write, void *buffer,
size_t *length, loff_t *ppos);
#endif
extern void wait_for_kprobe_optimizer(void);
#else
static inline void wait_for_kprobe_optimizer(void) { }
#endif /* CONFIG_OPTPROBES */
#ifdef CONFIG_KPROBES_ON_FTRACE
extern void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip,
struct ftrace_ops *ops, struct ftrace_regs *fregs);
extern int arch_prepare_kprobe_ftrace(struct kprobe *p);
#endif
int arch_check_ftrace_location(struct kprobe *p);
/* Get the kprobe at this addr (if any) - called with preemption disabled */
struct kprobe *get_kprobe(void *addr);
/* kprobe_running() will just return the current_kprobe on this CPU */
static inline struct kprobe *kprobe_running(void)
{
return (__this_cpu_read(current_kprobe));
}
static inline void reset_current_kprobe(void)
{
__this_cpu_write(current_kprobe, NULL);
}
static inline struct kprobe_ctlblk *get_kprobe_ctlblk(void)
{
return this_cpu_ptr(&kprobe_ctlblk);
}
kprobe_opcode_t *kprobe_lookup_name(const char *name, unsigned int offset);
int register_kprobe(struct kprobe *p);
void unregister_kprobe(struct kprobe *p);
int register_kprobes(struct kprobe **kps, int num);
void unregister_kprobes(struct kprobe **kps, int num);
unsigned long arch_deref_entry_point(void *);
int register_kretprobe(struct kretprobe *rp);
void unregister_kretprobe(struct kretprobe *rp);
int register_kretprobes(struct kretprobe **rps, int num);
void unregister_kretprobes(struct kretprobe **rps, int num);
void kprobe_flush_task(struct task_struct *tk);
void kprobe_free_init_mem(void);
int disable_kprobe(struct kprobe *kp);
int enable_kprobe(struct kprobe *kp);
void dump_kprobe(struct kprobe *kp);
void *alloc_insn_page(void);
void free_insn_page(void *page);
int kprobe_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
char *sym);
int arch_kprobe_get_kallsym(unsigned int *symnum, unsigned long *value,
char *type, char *sym);
#else /* !CONFIG_KPROBES: */
static inline int kprobes_built_in(void)
{
return 0;
}
static inline int kprobe_fault_handler(struct pt_regs *regs, int trapnr)
{
return 0;
}
static inline struct kprobe *get_kprobe(void *addr)
{
return NULL;
}
static inline struct kprobe *kprobe_running(void)
{
return NULL;
}
static inline int register_kprobe(struct kprobe *p)
{
return -ENOSYS;
}
static inline int register_kprobes(struct kprobe **kps, int num)
{
return -ENOSYS;
}
static inline void unregister_kprobe(struct kprobe *p)
{
}
static inline void unregister_kprobes(struct kprobe **kps, int num)
{
}
static inline int register_kretprobe(struct kretprobe *rp)
{
return -ENOSYS;
}
static inline int register_kretprobes(struct kretprobe **rps, int num)
{
return -ENOSYS;
}
static inline void unregister_kretprobe(struct kretprobe *rp)
{
}
static inline void unregister_kretprobes(struct kretprobe **rps, int num)
{
}
static inline void kprobe_flush_task(struct task_struct *tk)
{
}
static inline void kprobe_free_init_mem(void)
{
}
static inline int disable_kprobe(struct kprobe *kp)
{
return -ENOSYS;
}
static inline int enable_kprobe(struct kprobe *kp)
{
return -ENOSYS;
}
static inline bool within_kprobe_blacklist(unsigned long addr)
{
return true;
}
static inline int kprobe_get_kallsym(unsigned int symnum, unsigned long *value,
char *type, char *sym)
{
return -ERANGE;
}
#endif /* CONFIG_KPROBES */
static inline int disable_kretprobe(struct kretprobe *rp)
{
return disable_kprobe(&rp->kp);
}
static inline int enable_kretprobe(struct kretprobe *rp)
{
return enable_kprobe(&rp->kp);
}
#ifndef CONFIG_KPROBES
static inline bool is_kprobe_insn_slot(unsigned long addr)
{
return false;
}
#endif
#ifndef CONFIG_OPTPROBES
static inline bool is_kprobe_optinsn_slot(unsigned long addr)
{
return false;
}
#endif
/* Returns true if kprobes handled the fault */
static nokprobe_inline bool kprobe_page_fault(struct pt_regs *regs,
unsigned int trap)
{
if (!kprobes_built_in())
return false;
if (user_mode(regs))
return false;
/*
* To be potentially processing a kprobe fault and to be allowed
* to call kprobe_running(), we have to be non-preemptible.
*/
if (preemptible())
return false;
if (!kprobe_running())
return false;
return kprobe_fault_handler(regs, trap);
}
#endif /* _LINUX_KPROBES_H */