From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from Chamillionaire.breakpoint.cc (Chamillionaire.breakpoint.cc [91.216.245.30]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D0CE038C2BD; Wed, 4 Mar 2026 11:49:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.216.245.30 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772624990; cv=none; b=Ka890A5LIki4cxNHJFsVUmK0a0eD2bZYMOitQfV/J8jGm2/4e/R5BfoOGBEbU/v8r3PVBOrY7hzTl0lGDxm1U/9XMlzwqquxovKcvYNl9N9Z6coGZ1oXdJjMXA0MI4w9RPDO7/tkvy7hwDrWdqXTEAEPk4J25PM/pSUK1hlL/FI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772624990; c=relaxed/simple; bh=TuCsOZUN1adO9zguBW3T0kou2cWHPkKd9L0iAyqKmq8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=D1P8oAqRGvrajDZd5SiXr13bYBtZbwnKk4rRVfqfGgOf8DMuzeoP3pVxz1JJX7LQpE3ICfSO2C+Iy6xfC9u+Afg3e8HcH/ZWWQQHnR+7B+en8qK+lZOLRdMO9ypl9iSFNI6TaOeOmBaDfD6eOPaFtAgT1AysbOmv6FjKQE5Lt+0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=strlen.de; spf=pass smtp.mailfrom=Chamillionaire.breakpoint.cc; arc=none smtp.client-ip=91.216.245.30 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=strlen.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=Chamillionaire.breakpoint.cc Received: by Chamillionaire.breakpoint.cc (Postfix, from userid 1003) id 6A82A6026E; Wed, 04 Mar 2026 12:49:47 +0100 (CET) From: Florian Westphal To: Cc: Paolo Abeni , "David S. Miller" , Eric Dumazet , Jakub Kicinski , , pablo@netfilter.org Subject: [PATCH net-next 04/14] netfilter: nf_log_syslog: no longer acquire sk_callback_lock in nf_log_dump_sk_uid_gid() Date: Wed, 4 Mar 2026 12:49:11 +0100 Message-ID: <20260304114921.31042-5-fw@strlen.de> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20260304114921.31042-1-fw@strlen.de> References: <20260304114921.31042-1-fw@strlen.de> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Eric Dumazet After commit 983512f3a87f ("net: Drop the lock in skb_may_tx_timestamp()") from Sebastian Andrzej Siewior, apply the same logic in nf_log_dump_sk_uid_gid() to avoid touching sk_callback_lock. Signed-off-by: Eric Dumazet Signed-off-by: Florian Westphal --- net/netfilter/nf_log_syslog.c | 16 ++++++++++++---- 1 file changed, 12 insertions(+), 4 deletions(-) diff --git a/net/netfilter/nf_log_syslog.c b/net/netfilter/nf_log_syslog.c index 41503847d9d7..0507d67cad27 100644 --- a/net/netfilter/nf_log_syslog.c +++ b/net/netfilter/nf_log_syslog.c @@ -165,18 +165,26 @@ static struct nf_logger nf_arp_logger __read_mostly = { static void nf_log_dump_sk_uid_gid(struct net *net, struct nf_log_buf *m, struct sock *sk) { + const struct socket *sock; + const struct file *file; + if (!sk || !sk_fullsock(sk) || !net_eq(net, sock_net(sk))) return; - read_lock_bh(&sk->sk_callback_lock); - if (sk->sk_socket && sk->sk_socket->file) { - const struct cred *cred = sk->sk_socket->file->f_cred; + /* The sk pointer remains valid as long as the skb is. The sk_socket and + * file pointer may become NULL if the socket is closed. Both structures + * (including file->cred) are RCU freed which means they can be accessed + * within a RCU read section. + */ + sock = READ_ONCE(sk->sk_socket); + file = sock ? READ_ONCE(sock->file) : NULL; + if (file) { + const struct cred *cred = file->f_cred; nf_log_buf_add(m, "UID=%u GID=%u ", from_kuid_munged(&init_user_ns, cred->fsuid), from_kgid_munged(&init_user_ns, cred->fsgid)); } - read_unlock_bh(&sk->sk_callback_lock); } static noinline_for_stack int -- 2.52.0