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    Subject[PATCH 5.4 358/411] net: xfrm: unexport __init-annotated xfrm4_protocol_init()
    Date
    From: Masahiro Yamada <masahiroy@kernel.org>

    [ Upstream commit 4a388f08d8784af48f352193d2b72aaf167a57a1 ]

    EXPORT_SYMBOL and __init is a bad combination because the .init.text
    section is freed up after the initialization. Hence, modules cannot
    use symbols annotated __init. The access to a freed symbol may end up
    with kernel panic.

    modpost used to detect it, but it has been broken for a decade.

    Recently, I fixed modpost so it started to warn it again, then this
    showed up in linux-next builds.

    There are two ways to fix it:

    - Remove __init
    - Remove EXPORT_SYMBOL

    I chose the latter for this case because the only in-tree call-site,
    net/ipv4/xfrm4_policy.c is never compiled as modular.
    (CONFIG_XFRM is boolean)

    Fixes: 2f32b51b609f ("xfrm: Introduce xfrm_input_afinfo to access the the callbacks properly")
    Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
    Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
    Acked-by: Steffen Klassert <steffen.klassert@secunet.com>
    Signed-off-by: Jakub Kicinski <kuba@kernel.org>
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    net/ipv4/xfrm4_protocol.c | 1 -
    1 file changed, 1 deletion(-)

    diff --git a/net/ipv4/xfrm4_protocol.c b/net/ipv4/xfrm4_protocol.c
    index 8a4285712808..9031b7732fec 100644
    --- a/net/ipv4/xfrm4_protocol.c
    +++ b/net/ipv4/xfrm4_protocol.c
    @@ -298,4 +298,3 @@ void __init xfrm4_protocol_init(void)
    {
    xfrm_input_register_afinfo(&xfrm4_input_afinfo);
    }
    -EXPORT_SYMBOL(xfrm4_protocol_init);
    --
    2.35.1


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