From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 979D71F5849; Wed, 19 Mar 2025 14:39:29 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742395169; cv=none; b=UbhVrbXA81Xuq+hRfi0kl8MRXla6TUjiX4uPDtzCHN0W56bAO2E8LoHX+8VeXLqHqgp5SuF+fn4hoONIafchDVY6JCKnOalJ6PAK60SQj5BWvsvN6/lugT7YDftqXnaTD9xBMj0s5IGbkdsYvzs+a/eOcBYDmfdQDr4JRHFCivM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742395169; c=relaxed/simple; bh=dXHAuZRBX9+uth8zGPq9sFh+mLHTogGQ+3qWvcSfqZ0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Ftc4VOfMIJCrREOuS4VaVnfX0A1UP5FKORRo0c9ax00a1AzSAM0HpyNtAGsKm5WAshbGgrgVtCw8vqTTykGzUXGqSljmPoHPk4p2quhWiTJ06zwAsdQo8VSvGgGBtuGPQRa22DeOMl+/m0HBDUAM5JiOSTtk/1IdeQaZMBVPKGE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=skM/F585; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="skM/F585" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 698B9C4CEE4; Wed, 19 Mar 2025 14:39:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1742395169; bh=dXHAuZRBX9+uth8zGPq9sFh+mLHTogGQ+3qWvcSfqZ0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=skM/F585QLShIP2xIVp1WXq26sbiw8ZnBg+iKoi6X8P14xGLjxB6VhBYiKEqd0Ty/ BZ1iWilcSiXzV2FHkPSrkfr6A/Nil27KKlU0gJGeXESHD4yPDba1/F3kzQNifYHZyd FejiWR+CPnFoULG598z+ds7eZerMwRkAN4ZVUihw= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Breno Leitao , Simon Horman , Jakub Kicinski , Sasha Levin Subject: [PATCH 6.6 020/166] netpoll: hold rcu read lock in __netpoll_send_skb() Date: Wed, 19 Mar 2025 07:29:51 -0700 Message-ID: <20250319143020.530562722@linuxfoundation.org> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20250319143019.983527953@linuxfoundation.org> References: <20250319143019.983527953@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Breno Leitao [ Upstream commit 505ead7ab77f289f12d8a68ac83da068e4d4408b ] The function __netpoll_send_skb() is being invoked without holding the RCU read lock. This oversight triggers a warning message when CONFIG_PROVE_RCU_LIST is enabled: net/core/netpoll.c:330 suspicious rcu_dereference_check() usage! netpoll_send_skb netpoll_send_udp write_ext_msg console_flush_all console_unlock vprintk_emit To prevent npinfo from disappearing unexpectedly, ensure that __netpoll_send_skb() is protected with the RCU read lock. Fixes: 2899656b494dcd1 ("netpoll: take rcu_read_lock_bh() in netpoll_send_skb_on_dev()") Signed-off-by: Breno Leitao Reviewed-by: Simon Horman Link: https://patch.msgid.link/20250306-netpoll_rcu_v2-v2-1-bc4f5c51742a@debian.org Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- net/core/netpoll.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/net/core/netpoll.c b/net/core/netpoll.c index 1791462f1600a..1a4d2a61b060b 100644 --- a/net/core/netpoll.c +++ b/net/core/netpoll.c @@ -326,6 +326,7 @@ static int netpoll_owner_active(struct net_device *dev) static netdev_tx_t __netpoll_send_skb(struct netpoll *np, struct sk_buff *skb) { netdev_tx_t status = NETDEV_TX_BUSY; + netdev_tx_t ret = NET_XMIT_DROP; struct net_device *dev; unsigned long tries; /* It is up to the caller to keep npinfo alive. */ @@ -334,11 +335,12 @@ static netdev_tx_t __netpoll_send_skb(struct netpoll *np, struct sk_buff *skb) lockdep_assert_irqs_disabled(); dev = np->dev; + rcu_read_lock(); npinfo = rcu_dereference_bh(dev->npinfo); if (!npinfo || !netif_running(dev) || !netif_device_present(dev)) { dev_kfree_skb_irq(skb); - return NET_XMIT_DROP; + goto out; } /* don't get messages out of order, and no recursion */ @@ -377,7 +379,10 @@ static netdev_tx_t __netpoll_send_skb(struct netpoll *np, struct sk_buff *skb) skb_queue_tail(&npinfo->txq, skb); schedule_delayed_work(&npinfo->tx_work,0); } - return NETDEV_TX_OK; + ret = NETDEV_TX_OK; +out: + rcu_read_unlock(); + return ret; } netdev_tx_t netpoll_send_skb(struct netpoll *np, struct sk_buff *skb) -- 2.39.5