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    Subject[PATCH 5.16 0437/1039] netfilter: egress: avoid a lockdep splat
    Date
    From: Florian Westphal <fw@strlen.de>

    [ Upstream commit 6316136ec6e3dd1c302f7e7289a9ee46ecc610ae ]

    include/linux/netfilter_netdev.h:97 suspicious rcu_dereference_check() usage!
    2 locks held by sd-resolve/1100:
    0: ..(rcu_read_lock_bh){1:3}, at: ip_finish_output2
    1: ..(rcu_read_lock_bh){1:3}, at: __dev_queue_xmit
    __dev_queue_xmit+0 ..

    The helper has two callers, one uses rcu_read_lock, the other
    rcu_read_lock_bh(). Annotate the dereference to reflect this.

    Fixes: 42df6e1d221dd ("netfilter: Introduce egress hook")
    Signed-off-by: Florian Westphal <fw@strlen.de>
    Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    include/linux/netfilter_netdev.h | 2 +-
    1 file changed, 1 insertion(+), 1 deletion(-)

    diff --git a/include/linux/netfilter_netdev.h b/include/linux/netfilter_netdev.h
    index b71b57a83bb4f..b4dd96e4dc8dc 100644
    --- a/include/linux/netfilter_netdev.h
    +++ b/include/linux/netfilter_netdev.h
    @@ -94,7 +94,7 @@ static inline struct sk_buff *nf_hook_egress(struct sk_buff *skb, int *rc,
    return skb;
    #endif

    - e = rcu_dereference(dev->nf_hooks_egress);
    + e = rcu_dereference_check(dev->nf_hooks_egress, rcu_read_lock_bh_held());
    if (!e)
    return skb;

    --
    2.34.1


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