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Date: Mon, 6 Jun 2022 13:53:54 +0900
From: Masahiro Yamada <masahiroy@...nel.org>
To: "David S . Miller" <davem@...emloft.net>,
Jakub Kicinski <kuba@...nel.org>, netdev@...r.kernel.org
Cc: Eric Dumazet <edumazet@...gle.com>,
Paolo Abeni <pabeni@...hat.com>,
Masahiro Yamada <masahiroy@...nel.org>,
Stephen Rothwell <sfr@...b.auug.org.au>,
David Ahern <dsahern@...nel.org>,
Herbert Xu <herbert@...dor.apana.org.au>,
Hideaki YOSHIFUJI <yoshfuji@...ux-ipv6.org>,
Steffen Klassert <steffen.klassert@...unet.com>,
linux-kernel@...r.kernel.org
Subject: [PATCH 2/3] net: xfrm: unexport __init-annotated xfrm4_protocol_init()
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@...b.auug.org.au>
Signed-off-by: Masahiro Yamada <masahiroy@...nel.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 2fe5860c21d6..b146ce88c5d0 100644
--- a/net/ipv4/xfrm4_protocol.c
+++ b/net/ipv4/xfrm4_protocol.c
@@ -304,4 +304,3 @@ void __init xfrm4_protocol_init(void)
{
xfrm_input_register_afinfo(&xfrm4_input_afinfo);
}
-EXPORT_SYMBOL(xfrm4_protocol_init);
--
2.32.0
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