RE: [PATCH net-next 0/9] net/packet: KCSAN awareness

From: Willem de Bruijn <willemdebruijn.kernel@gmail.com>
To: Eric Dumazet <edumazet@google.com>,
	"David S . Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>
Cc: netdev@vger.kernel.org, Willem de Bruijn <willemb@google.com>,
	eric.dumazet@gmail.com, Eric Dumazet <edumazet@google.com>
Subject: RE: [PATCH net-next 0/9] net/packet: KCSAN awareness
Date: Thu, 16 Mar 2023 11:15:28 -0400	[thread overview]
Message-ID: <64133290485ad_3333c7208b2@willemb.c.googlers.com.notmuch> (raw)
In-Reply-To: <20230316011014.992179-1-edumazet@google.com>

Eric Dumazet wrote:
> This series is based on one syzbot report [1]
> 
> Seven 'flags/booleans' are converted to atomic bit variant.
> 
> po->xmit and po->tp_tstamp accesses get annotations.
> 
> [1]
> BUG: KCSAN: data-race in packet_rcv / packet_setsockopt
> 
> read-write to 0xffff88813dbe84e4 of 1 bytes by task 12312 on cpu 0:
> packet_setsockopt+0xb77/0xe60 net/packet/af_packet.c:3900
> __sys_setsockopt+0x212/0x2b0 net/socket.c:2252
> __do_sys_setsockopt net/socket.c:2263 [inline]
> __se_sys_setsockopt net/socket.c:2260 [inline]
> __x64_sys_setsockopt+0x62/0x70 net/socket.c:2260
> do_syscall_x64 arch/x86/entry/common.c:50 [inline]
> do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
> entry_SYSCALL_64_after_hwframe+0x63/0xcd
> 
> read to 0xffff88813dbe84e4 of 1 bytes by task 1911 on cpu 1:
> packet_rcv+0x4b1/0xa40 net/packet/af_packet.c:2187
> deliver_skb net/core/dev.c:2189 [inline]
> dev_queue_xmit_nit+0x3a9/0x620 net/core/dev.c:2259
> xmit_one+0x71/0x2a0 net/core/dev.c:3586
> dev_hard_start_xmit+0x72/0x120 net/core/dev.c:3606
> __dev_queue_xmit+0x91c/0x11c0 net/core/dev.c:4256
> dev_queue_xmit include/linux/netdevice.h:3008 [inline]
> neigh_hh_output include/net/neighbour.h:530 [inline]
> neigh_output include/net/neighbour.h:544 [inline]
> ip6_finish_output2+0x9e9/0xc30 net/ipv6/ip6_output.c:134
> __ip6_finish_output net/ipv6/ip6_output.c:195 [inline]
> ip6_finish_output+0x395/0x4f0 net/ipv6/ip6_output.c:206
> NF_HOOK_COND include/linux/netfilter.h:291 [inline]
> ip6_output+0x10e/0x210 net/ipv6/ip6_output.c:227
> dst_output include/net/dst.h:445 [inline]
> ip6_local_out+0x60/0x80 net/ipv6/output_core.c:161
> ip6tunnel_xmit include/net/ip6_tunnel.h:161 [inline]
> udp_tunnel6_xmit_skb+0x321/0x4a0 net/ipv6/ip6_udp_tunnel.c:109
> send6+0x2ed/0x3b0 drivers/net/wireguard/socket.c:152
> wg_socket_send_skb_to_peer+0xbb/0x120 drivers/net/wireguard/socket.c:178
> wg_packet_create_data_done drivers/net/wireguard/send.c:251 [inline]
> wg_packet_tx_worker+0x142/0x360 drivers/net/wireguard/send.c:276
> process_one_work+0x3d3/0x720 kernel/workqueue.c:2289
> worker_thread+0x618/0xa70 kernel/workqueue.c:2436
> kthread+0x1a9/0x1e0 kernel/kthread.c:376
> ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
> 
> value changed: 0x00 -> 0x01
> 
> Reported by Kernel Concurrency Sanitizer on:
> CPU: 1 PID: 1911 Comm: kworker/1:3 Not tainted 6.1.0-rc8-syzkaller-00164-g4cee37b3a4e6-dirty #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
> Workqueue: wg-crypt-wg0 wg_packet_tx_worker
> 
> Eric Dumazet (9):
>   net/packet: annotate accesses to po->xmit
>   net/packet: convert po->origdev to an atomic flag
>   net/packet: convert po->auxdata to an atomic flag
>   net/packet: annotate accesses to po->tp_tstamp
>   net/packet: convert po->tp_tx_has_off to an atomic flag
>   net/packet: convert po->tp_loss to an atomic flag
>   net/packet: convert po->has_vnet_hdr to an atomic flag
>   net/packet: convert po->running to an atomic flag
>   net/packet: convert po->pressure to an atomic flag
> 
>  net/packet/af_packet.c | 104 +++++++++++++++++++++--------------------
>  net/packet/diag.c      |  12 ++---
>  net/packet/internal.h  |  34 +++++++++++---
>  3 files changed, 87 insertions(+), 63 deletions(-)
> 
> -- 
> 2.40.0.rc2.332.ga46443480c-goog
> 

For the series:

Reviewed-by: Willem de Bruijn <willemb@google.com>