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kprobes: Fix build errors with CONFIG_KRETPROBES=n

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Max Filippov reported:

When building kernel with CONFIG_KRETPROBES=n kernel/kprobes.c
compilation fails with the following messages:

  kernel/kprobes.c: In function ‘recycle_rp_inst’:
  kernel/kprobes.c:1273:32: error: implicit declaration of function
                                   ‘get_kretprobe’

  kernel/kprobes.c: In function ‘kprobe_flush_task’:
  kernel/kprobes.c:1299:35: error: ‘struct task_struct’ has no member
                                   named ‘kretprobe_instances’

This came from the commit d741bf41d7 ("kprobes: Remove
kretprobe hash") which introduced get_kretprobe() and
kretprobe_instances member in task_struct when CONFIG_KRETPROBES=y,
but did not make recycle_rp_inst() and kprobe_flush_task()
depending on CONFIG_KRETPORBES.

Since those functions are only used for kretprobe, move those
functions into #ifdef CONFIG_KRETPROBE area.

Link: https://lkml.kernel.org/r/165163539094.74407.3838114721073251225.stgit@devnote2

Reported-by: Max Filippov <jcmvbkbc@gmail.com>
Fixes: d741bf41d7 ("kprobes: Remove kretprobe hash")
Cc: "Naveen N . Rao" <naveen.n.rao@linux.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: "David S . Miller" <davem@davemloft.net>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: stable@vger.kernel.org
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Tested-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
This commit is contained in:
Masami Hiramatsu 2022-05-04 12:36:31 +09:00 committed by Steven Rostedt (Google)
parent b27f266f74
commit 4399404918
2 changed files with 72 additions and 74 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
include/linux/kprobes.h
View File

@ -424,7 +424,7 @@ void unregister_kretprobe(struct kretprobe *rp);
int register_kretprobes(struct kretprobe **rps, int num);
void unregister_kretprobes(struct kretprobe **rps, int num);
#ifdef CONFIG_KRETPROBE_ON_RETHOOK
#if defined(CONFIG_KRETPROBE_ON_RETHOOK) || !defined(CONFIG_KRETPROBES)
#define kprobe_flush_task(tk) do {} while (0)
#else
void kprobe_flush_task(struct task_struct *tk);

144
kernel/kprobes.c
View File

@ -1257,79 +1257,6 @@ void kprobe_busy_end(void)
preempt_enable();
}
#if !defined(CONFIG_KRETPROBE_ON_RETHOOK)
static void free_rp_inst_rcu(struct rcu_head *head)
{
struct kretprobe_instance *ri = container_of(head, struct kretprobe_instance, rcu);
if (refcount_dec_and_test(&ri->rph->ref))
kfree(ri->rph);
kfree(ri);
}
NOKPROBE_SYMBOL(free_rp_inst_rcu);
static void recycle_rp_inst(struct kretprobe_instance *ri)
{
struct kretprobe *rp = get_kretprobe(ri);
if (likely(rp))
freelist_add(&ri->freelist, &rp->freelist);
else
call_rcu(&ri->rcu, free_rp_inst_rcu);
}
NOKPROBE_SYMBOL(recycle_rp_inst);
/*
* This function is called from delayed_put_task_struct() when a task is
* dead and cleaned up to recycle any kretprobe instances associated with
* this task. These left over instances represent probed functions that
* have been called but will never return.
*/
void kprobe_flush_task(struct task_struct *tk)
{
struct kretprobe_instance *ri;
struct llist_node *node;
/* Early boot, not yet initialized. */
if (unlikely(!kprobes_initialized))
return;
kprobe_busy_begin();
node = __llist_del_all(&tk->kretprobe_instances);
while (node) {
ri = container_of(node, struct kretprobe_instance, llist);
node = node->next;
recycle_rp_inst(ri);
}
kprobe_busy_end();
}
NOKPROBE_SYMBOL(kprobe_flush_task);
static inline void free_rp_inst(struct kretprobe *rp)
{
struct kretprobe_instance *ri;
struct freelist_node *node;
int count = 0;
node = rp->freelist.head;
while (node) {
ri = container_of(node, struct kretprobe_instance, freelist);
node = node->next;
kfree(ri);
count++;
}
if (refcount_sub_and_test(count, &rp->rph->ref)) {
kfree(rp->rph);
rp->rph = NULL;
}
}
#endif /* !CONFIG_KRETPROBE_ON_RETHOOK */
/* Add the new probe to 'ap->list'. */
static int add_new_kprobe(struct kprobe *ap, struct kprobe *p)
{
@ -1928,6 +1855,77 @@ static struct notifier_block kprobe_exceptions_nb = {
#ifdef CONFIG_KRETPROBES
#if !defined(CONFIG_KRETPROBE_ON_RETHOOK)
static void free_rp_inst_rcu(struct rcu_head *head)
{
struct kretprobe_instance *ri = container_of(head, struct kretprobe_instance, rcu);
if (refcount_dec_and_test(&ri->rph->ref))
kfree(ri->rph);
kfree(ri);
}
NOKPROBE_SYMBOL(free_rp_inst_rcu);
static void recycle_rp_inst(struct kretprobe_instance *ri)
{
struct kretprobe *rp = get_kretprobe(ri);
if (likely(rp))
freelist_add(&ri->freelist, &rp->freelist);
else
call_rcu(&ri->rcu, free_rp_inst_rcu);
}
NOKPROBE_SYMBOL(recycle_rp_inst);
/*
* This function is called from delayed_put_task_struct() when a task is
* dead and cleaned up to recycle any kretprobe instances associated with
* this task. These left over instances represent probed functions that
* have been called but will never return.
*/
void kprobe_flush_task(struct task_struct *tk)
{
struct kretprobe_instance *ri;
struct llist_node *node;
/* Early boot, not yet initialized. */
if (unlikely(!kprobes_initialized))
return;
kprobe_busy_begin();
node = __llist_del_all(&tk->kretprobe_instances);
while (node) {
ri = container_of(node, struct kretprobe_instance, llist);
node = node->next;
recycle_rp_inst(ri);
}
kprobe_busy_end();
}
NOKPROBE_SYMBOL(kprobe_flush_task);
static inline void free_rp_inst(struct kretprobe *rp)
{
struct kretprobe_instance *ri;
struct freelist_node *node;
int count = 0;
node = rp->freelist.head;
while (node) {
ri = container_of(node, struct kretprobe_instance, freelist);
node = node->next;
kfree(ri);
count++;
}
if (refcount_sub_and_test(count, &rp->rph->ref)) {
kfree(rp->rph);
rp->rph = NULL;
}
}
/* This assumes the 'tsk' is the current task or the is not running. */
static kprobe_opcode_t *__kretprobe_find_ret_addr(struct task_struct *tsk,
struct llist_node **cur)