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    Subject[PATCH 4.14 178/218] net: ipv6: unexport __init-annotated seg6_hmac_init()
    Date
    From: Masahiro Yamada <masahiroy@kernel.org>

    [ Upstream commit 5801f064e35181c71857a80ff18af4dbec3c5f5c ]

    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 caller (net/ipv6/seg6.c)
    and the callee (net/ipv6/seg6_hmac.c) belong to the same module.
    It seems an internal function call in ipv6.ko.

    Fixes: bf355b8d2c30 ("ipv6: sr: add core files for SR HMAC support")
    Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
    Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
    Signed-off-by: Jakub Kicinski <kuba@kernel.org>
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    net/ipv6/seg6_hmac.c | 1 -
    1 file changed, 1 deletion(-)

    diff --git a/net/ipv6/seg6_hmac.c b/net/ipv6/seg6_hmac.c
    index 558fe8cc6d43..ad5f8d521402 100644
    --- a/net/ipv6/seg6_hmac.c
    +++ b/net/ipv6/seg6_hmac.c
    @@ -405,7 +405,6 @@ int __init seg6_hmac_init(void)
    {
    return seg6_hmac_init_algo();
    }
    -EXPORT_SYMBOL(seg6_hmac_init);

    int __net_init seg6_hmac_net_init(struct net *net)
    {
    --
    2.35.1


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