From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id BA3CAC433EF for ; Mon, 31 Jan 2022 11:46:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1376277AbiAaLqc (ORCPT ); Mon, 31 Jan 2022 06:46:32 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49152 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1379787AbiAaLal (ORCPT ); Mon, 31 Jan 2022 06:30:41 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3EDFCC06134A; Mon, 31 Jan 2022 03:21:28 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 00135B82A5D; Mon, 31 Jan 2022 11:21:26 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 365B7C340E8; Mon, 31 Jan 2022 11:21:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1643628085; bh=UfKq2GQHSIkuB4vaUkVCYOWOTluH1D8DYB+0KuYdy7Y=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Pwff8NbHSh+On/2NPWd3WeTgukBrw8cERLGiyI7h75XGhh98tHBZUhDZJrk9DqbkG l5oibF6BS1ca6WrqDWizdzTJwrnLbFXIYp+oTOCXlLLpdutnbRdVfu35Ewk2syEPi5 1ZR4zJ05NVuNl4dqst+jG0bJrOg8qXt4Rjtc9cCE= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Eric Dumazet , syzbot , Jakub Kicinski Subject: [PATCH 5.16 120/200] ipv6: annotate accesses to fn->fn_sernum Date: Mon, 31 Jan 2022 11:56:23 +0100 Message-Id: <20220131105237.605653484@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220131105233.561926043@linuxfoundation.org> References: <20220131105233.561926043@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Eric Dumazet commit aafc2e3285c2d7a79b7ee15221c19fbeca7b1509 upstream. struct fib6_node's fn_sernum field can be read while other threads change it. Add READ_ONCE()/WRITE_ONCE() annotations. Do not change existing smp barriers in fib6_get_cookie_safe() and __fib6_update_sernum_upto_root() syzbot reported: BUG: KCSAN: data-race in fib6_clean_node / inet6_csk_route_socket write to 0xffff88813df62e2c of 4 bytes by task 1920 on cpu 1: fib6_clean_node+0xc2/0x260 net/ipv6/ip6_fib.c:2178 fib6_walk_continue+0x38e/0x430 net/ipv6/ip6_fib.c:2112 fib6_walk net/ipv6/ip6_fib.c:2160 [inline] fib6_clean_tree net/ipv6/ip6_fib.c:2240 [inline] __fib6_clean_all+0x1a9/0x2e0 net/ipv6/ip6_fib.c:2256 fib6_flush_trees+0x6c/0x80 net/ipv6/ip6_fib.c:2281 rt_genid_bump_ipv6 include/net/net_namespace.h:488 [inline] addrconf_dad_completed+0x57f/0x870 net/ipv6/addrconf.c:4230 addrconf_dad_work+0x908/0x1170 process_one_work+0x3f6/0x960 kernel/workqueue.c:2307 worker_thread+0x616/0xa70 kernel/workqueue.c:2454 kthread+0x1bf/0x1e0 kernel/kthread.c:359 ret_from_fork+0x1f/0x30 read to 0xffff88813df62e2c of 4 bytes by task 15701 on cpu 0: fib6_get_cookie_safe include/net/ip6_fib.h:285 [inline] rt6_get_cookie include/net/ip6_fib.h:306 [inline] ip6_dst_store include/net/ip6_route.h:234 [inline] inet6_csk_route_socket+0x352/0x3c0 net/ipv6/inet6_connection_sock.c:109 inet6_csk_xmit+0x91/0x1e0 net/ipv6/inet6_connection_sock.c:121 __tcp_transmit_skb+0x1323/0x1840 net/ipv4/tcp_output.c:1402 tcp_transmit_skb net/ipv4/tcp_output.c:1420 [inline] tcp_write_xmit+0x1450/0x4460 net/ipv4/tcp_output.c:2680 __tcp_push_pending_frames+0x68/0x1c0 net/ipv4/tcp_output.c:2864 tcp_push+0x2d9/0x2f0 net/ipv4/tcp.c:725 mptcp_push_release net/mptcp/protocol.c:1491 [inline] __mptcp_push_pending+0x46c/0x490 net/mptcp/protocol.c:1578 mptcp_sendmsg+0x9ec/0xa50 net/mptcp/protocol.c:1764 inet6_sendmsg+0x5f/0x80 net/ipv6/af_inet6.c:643 sock_sendmsg_nosec net/socket.c:705 [inline] sock_sendmsg net/socket.c:725 [inline] kernel_sendmsg+0x97/0xd0 net/socket.c:745 sock_no_sendpage+0x84/0xb0 net/core/sock.c:3086 inet_sendpage+0x9d/0xc0 net/ipv4/af_inet.c:834 kernel_sendpage+0x187/0x200 net/socket.c:3492 sock_sendpage+0x5a/0x70 net/socket.c:1007 pipe_to_sendpage+0x128/0x160 fs/splice.c:364 splice_from_pipe_feed fs/splice.c:418 [inline] __splice_from_pipe+0x207/0x500 fs/splice.c:562 splice_from_pipe fs/splice.c:597 [inline] generic_splice_sendpage+0x94/0xd0 fs/splice.c:746 do_splice_from fs/splice.c:767 [inline] direct_splice_actor+0x80/0xa0 fs/splice.c:936 splice_direct_to_actor+0x345/0x650 fs/splice.c:891 do_splice_direct+0x106/0x190 fs/splice.c:979 do_sendfile+0x675/0xc40 fs/read_write.c:1245 __do_sys_sendfile64 fs/read_write.c:1310 [inline] __se_sys_sendfile64 fs/read_write.c:1296 [inline] __x64_sys_sendfile64+0x102/0x140 fs/read_write.c:1296 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae value changed: 0x0000026f -> 0x00000271 Reported by Kernel Concurrency Sanitizer on: CPU: 0 PID: 15701 Comm: syz-executor.2 Not tainted 5.16.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 The Fixes tag I chose is probably arbitrary, I do not think we need to backport this patch to older kernels. Fixes: c5cff8561d2d ("ipv6: add rcu grace period before freeing fib6_node") Signed-off-by: Eric Dumazet Reported-by: syzbot Link: https://lore.kernel.org/r/20220120174112.1126644-1-eric.dumazet@gmail.com Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman --- include/net/ip6_fib.h | 2 +- net/ipv6/ip6_fib.c | 23 +++++++++++++---------- net/ipv6/route.c | 2 +- 3 files changed, 15 insertions(+), 12 deletions(-) --- a/include/net/ip6_fib.h +++ b/include/net/ip6_fib.h @@ -281,7 +281,7 @@ static inline bool fib6_get_cookie_safe( fn = rcu_dereference(f6i->fib6_node); if (fn) { - *cookie = fn->fn_sernum; + *cookie = READ_ONCE(fn->fn_sernum); /* pairs with smp_wmb() in __fib6_update_sernum_upto_root() */ smp_rmb(); status = true; --- a/net/ipv6/ip6_fib.c +++ b/net/ipv6/ip6_fib.c @@ -111,7 +111,7 @@ void fib6_update_sernum(struct net *net, fn = rcu_dereference_protected(f6i->fib6_node, lockdep_is_held(&f6i->fib6_table->tb6_lock)); if (fn) - fn->fn_sernum = fib6_new_sernum(net); + WRITE_ONCE(fn->fn_sernum, fib6_new_sernum(net)); } /* @@ -589,12 +589,13 @@ static int fib6_dump_table(struct fib6_t spin_unlock_bh(&table->tb6_lock); if (res > 0) { cb->args[4] = 1; - cb->args[5] = w->root->fn_sernum; + cb->args[5] = READ_ONCE(w->root->fn_sernum); } } else { - if (cb->args[5] != w->root->fn_sernum) { + int sernum = READ_ONCE(w->root->fn_sernum); + if (cb->args[5] != sernum) { /* Begin at the root if the tree changed */ - cb->args[5] = w->root->fn_sernum; + cb->args[5] = sernum; w->state = FWS_INIT; w->node = w->root; w->skip = w->count; @@ -1344,7 +1345,7 @@ static void __fib6_update_sernum_upto_ro /* paired with smp_rmb() in fib6_get_cookie_safe() */ smp_wmb(); while (fn) { - fn->fn_sernum = sernum; + WRITE_ONCE(fn->fn_sernum, sernum); fn = rcu_dereference_protected(fn->parent, lockdep_is_held(&rt->fib6_table->tb6_lock)); } @@ -2173,8 +2174,8 @@ static int fib6_clean_node(struct fib6_w }; if (c->sernum != FIB6_NO_SERNUM_CHANGE && - w->node->fn_sernum != c->sernum) - w->node->fn_sernum = c->sernum; + READ_ONCE(w->node->fn_sernum) != c->sernum) + WRITE_ONCE(w->node->fn_sernum, c->sernum); if (!c->func) { WARN_ON_ONCE(c->sernum == FIB6_NO_SERNUM_CHANGE); @@ -2542,7 +2543,7 @@ static void ipv6_route_seq_setup_walk(st iter->w.state = FWS_INIT; iter->w.node = iter->w.root; iter->w.args = iter; - iter->sernum = iter->w.root->fn_sernum; + iter->sernum = READ_ONCE(iter->w.root->fn_sernum); INIT_LIST_HEAD(&iter->w.lh); fib6_walker_link(net, &iter->w); } @@ -2570,8 +2571,10 @@ static struct fib6_table *ipv6_route_seq static void ipv6_route_check_sernum(struct ipv6_route_iter *iter) { - if (iter->sernum != iter->w.root->fn_sernum) { - iter->sernum = iter->w.root->fn_sernum; + int sernum = READ_ONCE(iter->w.root->fn_sernum); + + if (iter->sernum != sernum) { + iter->sernum = sernum; iter->w.state = FWS_INIT; iter->w.node = iter->w.root; WARN_ON(iter->w.skip); --- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -2802,7 +2802,7 @@ static void ip6_link_failure(struct sk_b if (from) { fn = rcu_dereference(from->fib6_node); if (fn && (rt->rt6i_flags & RTF_DEFAULT)) - fn->fn_sernum = -1; + WRITE_ONCE(fn->fn_sernum, -1); } } rcu_read_unlock();