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 D9CA919DFAB; Thu, 30 Jan 2025 14:15:54 +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=1738246554; cv=none; b=ZRPDmg7g8WmGVEFXCjF8onYp7B0KkAp38TcUmLnD6yLIGmCz74U1hLGDyrr/qvjbZabLs3SE6guvJT2wbichvLdWbkFuIKWSi6HpY6AqJNiY/mogeGng6zri57+NQCgd5qDji5zs4URle9pZ62TQLvUF2YpvY8ximF3ZqGj9ahM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738246554; c=relaxed/simple; bh=cf+63jA6mvjzQJpw72zDaZHKev77fLXGYXOfFdfKBuQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=VR9O4tizLDks6NNug4Yj8xOrboB82KYbQ9fxRYMJEe54m4cPTtA4qGvVd1oexY1rLDX9x19J5cCt8X2lWc6TgEiZyizRl2YAQwBfrAA9Q83e71Gsf2MPdJNA+i/rX+IojsI3i84d/0wvHVO6wnYzZQ7/IHKqCCjEdW2kOPbY6PA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=PnN4lDxC; 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="PnN4lDxC" Received: by smtp.kernel.org (Postfix) with ESMTPSA id F2D6CC4CEE2; Thu, 30 Jan 2025 14:15:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1738246554; bh=cf+63jA6mvjzQJpw72zDaZHKev77fLXGYXOfFdfKBuQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=PnN4lDxCceBMWOStoRApgu+i2PgM+tnT7/MTO8QT5Peh1s4C0IUYN9QCn/earpBjh CgcyHO+YXMKFXqGltOtXkTxq8dszifjzk6b/PUb8ws3YrKXT5WgumUlMD9m4urCUDl f+QSmJsD+SBPFGCtMCmRWhDiW94C2T7HsWNwRtvU= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Eric Dumazet , Ido Schimmel , Jakub Kicinski , Alva Lan Subject: [PATCH 6.6 32/43] ipv4: ip_tunnel: Fix suspicious RCU usage warning in ip_tunnel_find() Date: Thu, 30 Jan 2025 14:59:39 +0100 Message-ID: <20250130133500.194816590@linuxfoundation.org> X-Mailer: git-send-email 2.48.1 In-Reply-To: <20250130133458.903274626@linuxfoundation.org> References: <20250130133458.903274626@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev 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: Ido Schimmel commit 90e0569dd3d32f4f4d2ca691d3fa5a8a14a13c12 upstream. The per-netns IP tunnel hash table is protected by the RTNL mutex and ip_tunnel_find() is only called from the control path where the mutex is taken. Add a lockdep expression to hlist_for_each_entry_rcu() in ip_tunnel_find() in order to validate that the mutex is held and to silence the suspicious RCU usage warning [1]. [1] WARNING: suspicious RCU usage 6.12.0-rc3-custom-gd95d9a31aceb #139 Not tainted ----------------------------- net/ipv4/ip_tunnel.c:221 RCU-list traversed in non-reader section!! other info that might help us debug this: rcu_scheduler_active = 2, debug_locks = 1 1 lock held by ip/362: #0: ffffffff86fc7cb0 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x377/0xf60 stack backtrace: CPU: 12 UID: 0 PID: 362 Comm: ip Not tainted 6.12.0-rc3-custom-gd95d9a31aceb #139 Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 Call Trace: dump_stack_lvl+0xba/0x110 lockdep_rcu_suspicious.cold+0x4f/0xd6 ip_tunnel_find+0x435/0x4d0 ip_tunnel_newlink+0x517/0x7a0 ipgre_newlink+0x14c/0x170 __rtnl_newlink+0x1173/0x19c0 rtnl_newlink+0x6c/0xa0 rtnetlink_rcv_msg+0x3cc/0xf60 netlink_rcv_skb+0x171/0x450 netlink_unicast+0x539/0x7f0 netlink_sendmsg+0x8c1/0xd80 ____sys_sendmsg+0x8f9/0xc20 ___sys_sendmsg+0x197/0x1e0 __sys_sendmsg+0x122/0x1f0 do_syscall_64+0xbb/0x1d0 entry_SYSCALL_64_after_hwframe+0x77/0x7f Fixes: c54419321455 ("GRE: Refactor GRE tunneling code.") Suggested-by: Eric Dumazet Signed-off-by: Ido Schimmel Reviewed-by: Eric Dumazet Link: https://patch.msgid.link/20241023123009.749764-1-idosch@nvidia.com Signed-off-by: Jakub Kicinski Signed-off-by: Alva Lan Signed-off-by: Greg Kroah-Hartman --- net/ipv4/ip_tunnel.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/net/ipv4/ip_tunnel.c +++ b/net/ipv4/ip_tunnel.c @@ -218,7 +218,7 @@ static struct ip_tunnel *ip_tunnel_find( struct ip_tunnel *t = NULL; struct hlist_head *head = ip_bucket(itn, parms); - hlist_for_each_entry_rcu(t, head, hash_node) { + hlist_for_each_entry_rcu(t, head, hash_node, lockdep_rtnl_is_held()) { if (local == t->parms.iph.saddr && remote == t->parms.iph.daddr && link == READ_ONCE(t->parms.link) &&