Building the Linux kernel with Clang and LLVM
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From: Yabin Cui <yabinc@google.com>
To: Steffen Klassert <steffen.klassert@secunet.com>,
	Herbert Xu <herbert@gondor.apana.org.au>,
	 "David S. Miller" <davem@davemloft.net>,
	Eric Dumazet <edumazet@google.com>,
	 Jakub Kicinski <kuba@kernel.org>,
	Paolo Abeni <pabeni@redhat.com>,
	 Nathan Chancellor <nathan@kernel.org>,
	Nick Desaulniers <ndesaulniers@google.com>,
	 Bill Wendling <morbo@google.com>,
	Justin Stitt <justinstitt@google.com>
Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
	llvm@lists.linux.dev,  Yabin Cui <yabinc@google.com>
Subject: [PATCH] Fix initializing a static union variable
Date: Thu, 20 Jun 2024 11:17:36 -0700	[thread overview]
Message-ID: <20240620181736.1270455-1-yabinc@google.com> (raw)

saddr_wildcard is a static union variable initialized with {}.
But c11 standard doesn't guarantee initializing all fields as
zero for this case. As in https://godbolt.org/z/rWvdv6aEx,
clang only initializes the first field as zero, but the bits
corresponding to other (larger) members are undefined.

Signed-off-by: Yabin Cui <yabinc@google.com>
---
 net/xfrm/xfrm_state.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/xfrm/xfrm_state.c b/net/xfrm/xfrm_state.c
index 649bb739df0d..9bc69d703e5c 100644
--- a/net/xfrm/xfrm_state.c
+++ b/net/xfrm/xfrm_state.c
@@ -1139,7 +1139,7 @@ xfrm_state_find(const xfrm_address_t *daddr, const xfrm_address_t *saddr,
 		struct xfrm_policy *pol, int *err,
 		unsigned short family, u32 if_id)
 {
-	static xfrm_address_t saddr_wildcard = { };
+	static const xfrm_address_t saddr_wildcard;
 	struct net *net = xp_net(pol);
 	unsigned int h, h_wildcard;
 	struct xfrm_state *x, *x0, *to_put;
-- 
2.45.2.741.gdbec12cfda-goog


             reply	other threads:[~2024-06-20 18:17 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-06-20 18:17 Yabin Cui [this message]
2024-06-20 19:31 ` [PATCH] Fix initializing a static union variable Nick Desaulniers
2024-06-20 19:47   ` Nick Desaulniers
2024-06-20 19:54     ` Nick Desaulniers
2024-06-21 11:24       ` Ballman, Aaron
2024-06-21 20:49         ` Yabin Cui
2024-06-21 11:07   ` Herbert Xu
2024-06-23 16:51     ` Linus Torvalds
2024-06-23 17:05       ` Linus Torvalds
2024-06-24 18:04         ` Yabin Cui
2024-06-21 11:01 ` Przemek Kitszel

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