From: Masahiro Yamada <masahiroy@kernel.org>
To: "David S . Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>,
netdev@vger.kernel.org
Cc: Eric Dumazet <edumazet@google.com>,
Paolo Abeni <pabeni@redhat.com>,
Masahiro Yamada <masahiroy@kernel.org>,
Stephen Rothwell <sfr@canb.auug.org.au>,
David Ahern <dsahern@kernel.org>,
David Lebrun <david.lebrun@uclouvain.be>,
Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>,
linux-kernel@vger.kernel.org
Subject: [PATCH 3/3] net: ipv6: unexport __init-annotated seg6_hmac_init()
Date: Mon, 6 Jun 2022 13:53:55 +0900 [thread overview]
Message-ID: <20220606045355.4160711-4-masahiroy@kernel.org> (raw)
In-Reply-To: <20220606045355.4160711-1-masahiroy@kernel.org>
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>
---
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 29bc4e7c3046..6de01185cc68 100644
--- a/net/ipv6/seg6_hmac.c
+++ b/net/ipv6/seg6_hmac.c
@@ -399,7 +399,6 @@ 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)
{
--
2.32.0
next prev parent reply other threads:[~2022-06-06 5:29 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-06-06 4:53 [PATCH 0/3] net: unexport some symbols that are annotated __init Masahiro Yamada
2022-06-06 4:53 ` [PATCH 1/3] net: mdio: unexport __init-annotated mdio_bus_init() Masahiro Yamada
2022-06-06 8:09 ` Florian Fainelli
2022-06-06 8:25 ` Russell King (Oracle)
2022-06-06 4:53 ` [PATCH 2/3] net: xfrm: unexport __init-annotated xfrm4_protocol_init() Masahiro Yamada
2022-06-07 11:18 ` Paolo Abeni
2022-06-08 5:39 ` Steffen Klassert
2022-06-06 4:53 ` Masahiro Yamada [this message]
2022-06-08 17:20 ` [PATCH 0/3] net: unexport some symbols that are annotated __init patchwork-bot+netdevbpf
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