From: Jakub Kicinski <kuba@kernel.org>
To: Jakub Sitnicki <jakub@cloudflare.com>
Cc: netdev@vger.kernel.org, kernel-team@cloudflare.com,
"David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Paolo Abeni <pabeni@redhat.com>,
Haowei Yan <g1042620637@gmail.com>,
Tom Parkin <tparkin@katalix.com>
Subject: Re: [PATCH net v2] l2tp: Serialize access to sk_user_data with sock lock
Date: Tue, 16 Aug 2022 18:41:50 -0700 [thread overview]
Message-ID: <20220816184150.78d6e3e3@kernel.org> (raw)
In-Reply-To: <20220815130107.149345-1-jakub@cloudflare.com>
On Mon, 15 Aug 2022 15:01:07 +0200 Jakub Sitnicki wrote:
> sk->sk_user_data has multiple users, which are not compatible with each
> other. To synchronize the users, any check-if-unused-and-set access to the
> pointer has to happen with sock lock held.
>
> l2tp currently fails to grab the lock when modifying the underlying tunnel
> socket. Fix it by adding appropriate locking.
>
> We don't to grab the lock when l2tp clears sk_user_data, because it happens
> only in sk->sk_destruct, when the sock is going away.
Note to other netdev maintainers that based on the discussion about
the reuseport locking it's unclear whether we shouldn't also take
the callback lock...
next prev parent reply other threads:[~2022-08-17 1:41 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-15 13:01 [PATCH net v2] l2tp: Serialize access to sk_user_data with sock lock Jakub Sitnicki
2022-08-15 13:21 ` Tom Parkin
2022-08-15 13:26 ` Jakub Sitnicki
2022-08-15 13:39 ` Tom Parkin
2022-08-17 1:41 ` Jakub Kicinski [this message]
2022-08-17 14:33 ` Jakub Sitnicki
2022-08-17 15:51 ` Jakub Kicinski
2022-08-17 15:56 ` Jakub Sitnicki
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