On Sun, 11 Nov 2018 11:43:49 -0800
"Paul E. McKenney" <paul...@linux.ibm.com> wrote:

> Now that synchronize_rcu() waits for preempt-disable regions of code
> as well as RCU read-side critical sections, synchronize_sched() can be
> replaced by synchronize_rcu().  This commit therefore makes this change.

Would you mean synchronize_rcu() can ensure that any interrupt handler
(which should run under preempt-disable state) run out (even on non-preemptive
kernel)?
If so, I agree with these changes.

Thank you,

> 
> Signed-off-by: Paul E. McKenney <paul...@linux.ibm.com>
> Cc: "Naveen N. Rao" <naveen.n....@linux.ibm.com>
> Cc: Anil S Keshavamurthy <anil.s.keshavamur...@intel.com>
> Cc: "David S. Miller" <da...@davemloft.net>
> Cc: Masami Hiramatsu <mhira...@kernel.org>
> ---
>  kernel/kprobes.c | 10 +++++-----
>  1 file changed, 5 insertions(+), 5 deletions(-)
> 
> diff --git a/kernel/kprobes.c b/kernel/kprobes.c
> index 90e98e233647..08e31d863191 100644
> --- a/kernel/kprobes.c
> +++ b/kernel/kprobes.c
> @@ -229,7 +229,7 @@ static int collect_garbage_slots(struct kprobe_insn_cache 
> *c)
>       struct kprobe_insn_page *kip, *next;
>  
>       /* Ensure no-one is interrupted on the garbages */
> -     synchronize_sched();
> +     synchronize_rcu();
>  
>       list_for_each_entry_safe(kip, next, &c->pages, list) {
>               int i;
> @@ -1382,7 +1382,7 @@ static int register_aggr_kprobe(struct kprobe *orig_p, 
> struct kprobe *p)
>                       if (ret) {
>                               ap->flags |= KPROBE_FLAG_DISABLED;
>                               list_del_rcu(&p->list);
> -                             synchronize_sched();
> +                             synchronize_rcu();
>                       }
>               }
>       }
> @@ -1597,7 +1597,7 @@ int register_kprobe(struct kprobe *p)
>               ret = arm_kprobe(p);
>               if (ret) {
>                       hlist_del_rcu(&p->hlist);
> -                     synchronize_sched();
> +                     synchronize_rcu();
>                       goto out;
>               }
>       }
> @@ -1776,7 +1776,7 @@ void unregister_kprobes(struct kprobe **kps, int num)
>                       kps[i]->addr = NULL;
>       mutex_unlock(&kprobe_mutex);
>  
> -     synchronize_sched();
> +     synchronize_rcu();
>       for (i = 0; i < num; i++)
>               if (kps[i]->addr)
>                       __unregister_kprobe_bottom(kps[i]);
> @@ -1966,7 +1966,7 @@ void unregister_kretprobes(struct kretprobe **rps, int 
> num)
>                       rps[i]->kp.addr = NULL;
>       mutex_unlock(&kprobe_mutex);
>  
> -     synchronize_sched();
> +     synchronize_rcu();
>       for (i = 0; i < num; i++) {
>               if (rps[i]->kp.addr) {
>                       __unregister_kprobe_bottom(&rps[i]->kp);
> -- 
> 2.17.1
> 


-- 
Masami Hiramatsu <mhira...@kernel.org>

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