Re: [PATCH mptcp-net 0/2] mptcp: "fix suspicious RCU usage" warnings

[Paolo Abeni <pabeni@redhat.com>]

Hi,

On 10/16/24 21:05, Matthieu Baerts (NGI0) wrote:
> Enabling PROVE_RCU_LIST (and RCU_EXPERT) shows list_for_each_entry_rcu()
> from mptcp_sched_find() not being used with RCU read lock held.
> 
> The first patch is a fix for -net. The other one is for a commit that is
> only in our tree.
> 
> Link: https://lore.kernel.org/20241016011144.3058445-1-kuba@kernel.org
> Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
> ---
> Matthieu Baerts (NGI0) (2):
>        mptcp: init: protect sched with rcu_read_lock
>        Squash to "bpf: Add bpf_mptcp_sched_ops"
> 
>   net/mptcp/bpf.c      | 10 +++++++---
>   net/mptcp/protocol.c |  2 ++
>   2 files changed, 9 insertions(+), 3 deletions(-)
> ---
> base-commit: baccd7675477b1db387aa71b48c3312b5fb67a5d
> change-id: 20241016-mptcp-sched-find-rcu-649ce3399334
> 
> Best regards,

Only slightly related, but mptcp_get_available_schedulers() currently 
acquires both the rcu and the sched_list lock. I think the latter is not 
needed and should be dropped.

Cheers,

Paolo