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KCSAN: data-race in dev_fetch_sw_netstats / wg_packet_rx_poll

Status: auto-closed as invalid on 2020/11/24 20:34
Subsystems: wireguard
[Documentation on labels]
First crash: 1276d, last: 1276d

Sample crash report:
batman_adv: batadv0: Interface activated: batadv_slave_1
==================================================================
BUG: KCSAN: data-race in dev_fetch_sw_netstats / wg_packet_rx_poll

read-write to 0xffffe8ffffc5f900 of 8 bytes by interrupt on cpu 0:
 update_rx_stats drivers/net/wireguard/receive.c:26 [inline]
 wg_packet_consume_data_done drivers/net/wireguard/receive.c:364 [inline]
 wg_packet_rx_poll+0xfd2/0x1280 drivers/net/wireguard/receive.c:482
 napi_poll+0x178/0x4c0 net/core/dev.c:6759
 net_rx_action+0x1ba/0x520 net/core/dev.c:6829
 __do_softirq+0x198/0x331 kernel/softirq.c:298
 asm_call_irq_on_stack+0xf/0x20
 __run_on_irqstack arch/x86/include/asm/irq_stack.h:26 [inline]
 run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:77 [inline]
 do_softirq_own_stack+0x5b/0x70 arch/x86/kernel/irq_64.c:77
 do_softirq+0x86/0xb0 kernel/softirq.c:343
 __local_bh_enable_ip+0x63/0x70 kernel/softirq.c:195
 __raw_spin_unlock_bh include/linux/spinlock_api_smp.h:176 [inline]
 _raw_spin_unlock_bh+0x33/0x40 kernel/locking/spinlock.c:207
 spin_unlock_bh include/linux/spinlock.h:399 [inline]
 ptr_ring_consume_bh include/linux/ptr_ring.h:367 [inline]
 wg_packet_decrypt_worker+0x6f2/0x730 drivers/net/wireguard/receive.c:507
 process_one_work+0x3e1/0x950 kernel/workqueue.c:2272
 worker_thread+0x635/0xb90 kernel/workqueue.c:2418
 kthread+0x1ff/0x220 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296

read to 0xffffe8ffffc5f900 of 8 bytes by task 25737 on cpu 1:
 dev_fetch_sw_netstats+0x9b/0x160 net/core/dev.c:10351
 ip_tunnel_get_stats64+0x38/0x40 net/ipv4/ip_tunnel_core.c:437
 dev_get_stats+0x63/0x160 net/core/dev.c:10318
 rtnl_fill_stats+0x45/0x320 net/core/rtnetlink.c:1209
 rtnl_fill_ifinfo+0xe92/0x2430 net/core/rtnetlink.c:1781
 rtmsg_ifinfo_build_skb+0xa2/0x130 net/core/rtnetlink.c:3808
 rtmsg_ifinfo_event net/core/rtnetlink.c:3840 [inline]
 rtmsg_ifinfo+0x55/0xc0 net/core/rtnetlink.c:3849
 __dev_notify_flags+0x63/0x3a0 net/core/dev.c:8453
 dev_change_flags+0xa2/0xc0 net/core/dev.c:8495
 do_setlink+0x73e/0x21d0 net/core/rtnetlink.c:2706
 __rtnl_newlink net/core/rtnetlink.c:3374 [inline]
 rtnl_newlink+0xec9/0x13a0 net/core/rtnetlink.c:3500
 rtnetlink_rcv_msg+0x722/0x7c0 net/core/rtnetlink.c:5563
 netlink_rcv_skb+0x13e/0x240 net/netlink/af_netlink.c:2494
 rtnetlink_rcv+0x18/0x20 net/core/rtnetlink.c:5581
 netlink_unicast_kernel net/netlink/af_netlink.c:1304 [inline]
 netlink_unicast+0x5df/0x6b0 net/netlink/af_netlink.c:1330
 netlink_sendmsg+0x6f8/0x7c0 net/netlink/af_netlink.c:1919
 sock_sendmsg_nosec net/socket.c:651 [inline]
 sock_sendmsg net/socket.c:671 [inline]
 __sys_sendto+0x2ae/0x380 net/socket.c:1992
 __do_sys_sendto net/socket.c:2004 [inline]
 __se_sys_sendto net/socket.c:2000 [inline]
 __x64_sys_sendto+0x74/0x90 net/socket.c:2000
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 25737 Comm: syz-executor.4 Not tainted 5.9.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2020/10/20 20:27 upstream 270315b8235e ff4a3345 .config console log report info ci2-upstream-kcsan-gce
* Struck through repros no longer work on HEAD.