From: Cong Wang <xiyou.wangcong@gmail.com>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: David Miller <davem@davemloft.net>,
Linux Kernel Network Developers <netdev@vger.kernel.org>,
Andrey Konovalov <andreyknvl@google.com>,
Eric Dumazet <edumazet@google.com>
Subject: Re: [Patch net] ipv4: restore rt->fi for reference counting
Date: Wed, 10 May 2017 09:32:12 -0700 [thread overview]
Message-ID: <CAM_iQpVFoyDCemfr_fVD7+zN6-Cb5sv_c9XRqA7Oa9sx5cj2fg@mail.gmail.com> (raw)
In-Reply-To: <1494373805.7796.98.camel@edumazet-glaptop3.roam.corp.google.com>
On Tue, May 9, 2017 at 4:50 PM, Eric Dumazet <eric.dumazet@gmail.com> wrote:
> On Tue, 2017-05-09 at 16:35 -0700, Cong Wang wrote:
>
>> All of them take RCU read lock, so, as I explained in the code comment,
>> they all should be fine because of synchronize_net() on unregister path.
>> Do you see anything otherwise?
>
> They might take rcu lock, but compiler is still allowed to read
> fi->fib_dev multiple times, and crashes might happen.
>
> You will need to audit all code and fix it, using proper
> rcu_dereference() or similar code ensuring compiler wont do stupid
> things.
>
Point taken. But without my patch, nh_dev is supposed to be protected
by RCU too, it is freed in a rcu callback and dereferenced like:
struct in_device *in_dev = __in_dev_get_rcu(nh->nh_dev);
next prev parent reply other threads:[~2017-05-10 16:32 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-05-04 21:54 [Patch net] ipv4: restore rt->fi for reference counting Cong Wang
2017-05-07 18:53 ` Eric Dumazet
2017-05-08 18:35 ` David Miller
2017-05-09 0:01 ` Eric Dumazet
2017-05-09 1:22 ` David Miller
2017-05-09 2:18 ` Eric Dumazet
2017-05-09 2:35 ` David Miller
2017-05-09 16:44 ` Cong Wang
2017-05-09 16:56 ` Eric Dumazet
2017-05-09 20:56 ` Cong Wang
2017-05-09 22:07 ` Cong Wang
2017-05-09 22:52 ` Eric Dumazet
2017-05-09 22:54 ` Eric Dumazet
2017-05-09 23:09 ` Eric Dumazet
2017-05-09 23:35 ` Cong Wang
2017-05-09 23:50 ` Eric Dumazet
2017-05-10 16:32 ` Cong Wang [this message]
2017-05-09 23:51 ` Eric Dumazet
2017-05-10 16:40 ` Cong Wang
2017-05-10 7:38 ` Julian Anastasov
2017-05-10 17:00 ` Cong Wang
2017-05-10 19:51 ` Julian Anastasov
2017-05-12 0:07 ` Cong Wang
2017-05-12 1:22 ` Cong Wang
2017-05-12 4:55 ` Eric Dumazet
2017-05-12 17:49 ` Cong Wang
2017-05-12 6:39 ` Julian Anastasov
2017-05-12 17:27 ` Cong Wang
2017-05-12 20:58 ` Cong Wang
2017-05-12 21:13 ` Cong Wang
2017-05-12 21:27 ` Julian Anastasov
2017-05-15 18:34 ` Cong Wang
2017-05-15 20:37 ` Julian Anastasov
2017-05-15 22:13 ` Cong Wang
2017-05-16 7:46 ` Julian Anastasov
2017-05-16 17:53 ` Cong Wang
2017-05-16 18:16 ` Cong Wang
[not found] ` <1495572267.6465.79.camel@edumazet-glaptop3.roam.corp.google.com>
[not found] ` <CAM_iQpX0X3h4Sf+bHUXdJgBqUTxNat0FBT0PeRpLYWju9ci59Q@mail.gmail.com>
[not found] ` <CANn89i+mPR+7-AVO2Dsd=KfO=COOVY42AKjwEs=0=GUCML6HUQ@mail.gmail.com>
[not found] ` <CAM_iQpUfLmN3yWsCfpx4ZTptBnuYFNuY5CjBKdwoDpvH5K8P=w@mail.gmail.com>
[not found] ` <1495665921.6465.95.camel@edumazet-glaptop3.roam.corp.google.com>
2017-05-25 21:27 ` [PATCH net] ipv4: add reference counting to metrics Eric Dumazet
2017-05-25 22:25 ` Julian Anastasov
2017-05-26 17:08 ` Cong Wang
2017-05-26 17:13 ` Eric Dumazet
2017-05-26 17:26 ` Cong Wang
2017-05-26 18:58 ` David Miller
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