syzbot


KCSAN: data-race in __dev_change_flags / can_send

Status: auto-obsoleted due to no activity on 2025/07/30 07:42
Subsystems: net
[Documentation on labels]
First crash: 83d, last: 83d

Sample crash report:
==================================================================
BUG: KCSAN: data-race in __dev_change_flags / can_send

read-write to 0xffff8881364500b0 of 4 bytes by task 31666 on cpu 0:
 __dev_change_flags+0x9a/0x400 net/core/dev.c:9432
 netif_change_flags+0x5a/0xd0 net/core/dev.c:9521
 do_setlink+0x9d2/0x2810 net/core/rtnetlink.c:3141
 rtnl_changelink net/core/rtnetlink.c:3759 [inline]
 __rtnl_newlink net/core/rtnetlink.c:3918 [inline]
 rtnl_newlink+0xe75/0x12d0 net/core/rtnetlink.c:4055
 rtnetlink_rcv_msg+0x5fe/0x6d0 net/core/rtnetlink.c:6944
 netlink_rcv_skb+0x123/0x220 net/netlink/af_netlink.c:2534
 rtnetlink_rcv+0x1c/0x30 net/core/rtnetlink.c:6971
 netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline]
 netlink_unicast+0x59e/0x670 net/netlink/af_netlink.c:1339
 netlink_sendmsg+0x58b/0x6b0 net/netlink/af_netlink.c:1883
 sock_sendmsg_nosec net/socket.c:712 [inline]
 __sock_sendmsg+0x145/0x180 net/socket.c:727
 ____sys_sendmsg+0x31e/0x4e0 net/socket.c:2566
 ___sys_sendmsg+0x17b/0x1d0 net/socket.c:2620
 __sys_sendmsg net/socket.c:2652 [inline]
 __do_sys_sendmsg net/socket.c:2657 [inline]
 __se_sys_sendmsg net/socket.c:2655 [inline]
 __x64_sys_sendmsg+0xd4/0x160 net/socket.c:2655
 x64_sys_call+0x2999/0x2fb0 arch/x86/include/generated/asm/syscalls_64.h:47
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff8881364500b0 of 4 bytes by interrupt on cpu 1:
 can_send+0x361/0x690 net/can/af_can.c:259
 j1939_send_one+0x1ab/0x1e0 net/can/j1939/main.c:353
 j1939_tp_tx_dat net/can/j1939/transport.c:647 [inline]
 j1939_session_tx_dat net/can/j1939/transport.c:839 [inline]
 j1939_xtp_txnext_transmiter net/can/j1939/transport.c:901 [inline]
 j1939_tp_txtimer+0xce9/0x1800 net/can/j1939/transport.c:1161
 __run_hrtimer kernel/time/hrtimer.c:1761 [inline]
 __hrtimer_run_queues+0x20c/0x5a0 kernel/time/hrtimer.c:1825
 hrtimer_run_softirq+0xe0/0x2c0 kernel/time/hrtimer.c:1842
 handle_softirqs+0xb7/0x290 kernel/softirq.c:579
 do_softirq+0x5d/0x90 kernel/softirq.c:480
 __local_bh_enable_ip+0x70/0x80 kernel/softirq.c:407
 __raw_spin_unlock_bh include/linux/spinlock_api_smp.h:167 [inline]
 _raw_spin_unlock_bh+0x36/0x40 kernel/locking/spinlock.c:210
 spin_unlock_bh include/linux/spinlock.h:396 [inline]
 batadv_nc_purge_paths+0x22b/0x270 net/batman-adv/network-coding.c:471
 batadv_nc_worker+0x3ff/0xae0 net/batman-adv/network-coding.c:722
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0x4cb/0x9d0 kernel/workqueue.c:3321
 worker_thread+0x582/0x770 kernel/workqueue.c:3402
 kthread+0x486/0x510 kernel/kthread.c:464
 ret_from_fork+0xda/0x150 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

value changed: 0x00000081 -> 0x0000f0a1

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 13819 Comm: kworker/u8:30 Not tainted 6.15.0-syzkaller-11796-g5abc7438f1e9 #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Workqueue: bat_events batadv_nc_worker
==================================================================
vcan0: j1939_session_tx_dat: 0xffff888111e5aa00: queue data error: -100
vcan0: j1939_xtp_rx_dpo: no connection found
vcan0: j1939_xtp_rx_dpo: no connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found
vcan0: j1939_xtp_rx_dat: no tx connection found
vcan0: j1939_xtp_rx_dat: no rx connection found

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/06/04 07:37 upstream 5abc7438f1e9 a30356b7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __dev_change_flags / can_send
* Struck through repros no longer work on HEAD.