From: Masami Hiramatsu mhiramat@kernel.org
commit 43994049180704fd1faf78623fabd9a5cd443708 upstream.
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 d741bf41d7c7 ("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@devno...
Reported-by: Max Filippov jcmvbkbc@gmail.com Fixes: d741bf41d7c7 ("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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- include/linux/kprobes.h | 2 kernel/kprobes.c | 144 +++++++++++++++++++++++------------------------- 2 files changed, 72 insertions(+), 74 deletions(-)
--- a/include/linux/kprobes.h +++ b/include/linux/kprobes.h @@ -424,7 +424,7 @@ void unregister_kretprobe(struct kretpro 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); --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -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_exce #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)