From: Alexei Starovoitov <ast@plumgrid.com>
To: Wang Nan <wangnan0@huawei.com>
Cc: lizefan@huawei.com, linux-kernel@vger.kernel.org, pi3orama@163.com
Subject: Re: [PATCH] bpf: fix a race between perf_event_fd and kprobe freeing
Date: Fri, 15 May 2015 08:59:04 -0700 [thread overview]
Message-ID: <555617C8.1070309@plumgrid.com> (raw)
In-Reply-To: <1431687144-130670-1-git-send-email-wangnan0@huawei.com>
On 5/15/15 3:52 AM, Wang Nan wrote:
> According to Alexei Starovoitov (http://lkml.org/lkml/2015/5/15/29),
> there is racing between perf_event_fd and kprobe freeing:
...
> And he suggest to call perf_event_free_bpf_prog() from __free_event()
> instead of free_event_rcu() will fix the race,
...
> @@ -3564,6 +3563,8 @@ static void __free_event(struct perf_event *event)
> module_put(event->pmu->module);
> }
>
> + perf_event_free_bpf_prog(event);
> +
> call_rcu(&event->rcu_head, free_event_rcu);
> }
I don't think that's the right place. It needs to be before destroy().
I will send a patch soon.
prev parent reply other threads:[~2015-05-15 15:59 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-05-15 10:52 [PATCH] bpf: fix a race between perf_event_fd and kprobe freeing Wang Nan
2015-05-15 15:59 ` Alexei Starovoitov [this message]
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