================================================================== BUG: KCSAN: data-race in _prb_read_valid / prb_reserve write to 0xffffffff868e1210 of 88 bytes by task 10 on cpu 0: prb_reserve+0x696/0xaf0 kernel/printk/printk_ringbuffer.c:1635 vprintk_store+0x56d/0x860 kernel/printk/printk.c:2326 vprintk_emit+0x178/0x650 kernel/printk/printk.c:2426 vprintk_default+0x26/0x30 kernel/printk/printk.c:2465 vprintk+0x1d/0x30 kernel/printk/printk_safe.c:82 _printk+0x79/0xa0 kernel/printk/printk.c:2475 ip6_tnl_xmit_ctl+0x3b0/0x3d0 net/ipv6/ip6_tunnel.c:-1 ip6gre_tunnel_xmit+0x14d/0xb30 net/ipv6/ip6_gre.c:917 __netdev_start_xmit include/linux/netdevice.h:5203 [inline] netdev_start_xmit include/linux/netdevice.h:5212 [inline] xmit_one net/core/dev.c:3776 [inline] dev_hard_start_xmit+0x12c/0x3d0 net/core/dev.c:3792 sch_direct_xmit+0x192/0x550 net/sched/sch_generic.c:343 __dev_xmit_skb net/core/dev.c:4018 [inline] __dev_queue_xmit+0xe4f/0x1fb0 net/core/dev.c:4595 dev_queue_xmit include/linux/netdevice.h:3350 [inline] neigh_hh_output include/net/neighbour.h:523 [inline] neigh_output include/net/neighbour.h:537 [inline] ip6_finish_output2+0xa3c/0xd30 net/ipv6/ip6_output.c:141 __ip6_finish_output net/ipv6/ip6_output.c:-1 [inline] ip6_finish_output+0x3a2/0x530 net/ipv6/ip6_output.c:226 NF_HOOK_COND include/linux/netfilter.h:303 [inline] ip6_output+0xfd/0x240 net/ipv6/ip6_output.c:247 dst_output include/net/dst.h:459 [inline] NF_HOOK include/linux/netfilter.h:314 [inline] mld_sendpack+0x427/0x6e0 net/ipv6/mcast.c:1868 mld_send_cr net/ipv6/mcast.c:2169 [inline] mld_ifc_work+0x55c/0x840 net/ipv6/mcast.c:2702 process_one_work kernel/workqueue.c:3238 [inline] process_scheduled_works+0x4cb/0x9d0 kernel/workqueue.c:3319 worker_thread+0x582/0x770 kernel/workqueue.c:3400 kthread+0x486/0x510 kernel/kthread.c:464 ret_from_fork+0x4b/0x60 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 read to 0xffffffff868e1210 of 8 bytes by task 28986 on cpu 1: desc_read kernel/printk/printk_ringbuffer.c:486 [inline] prb_first_seq kernel/printk/printk_ringbuffer.c:1957 [inline] _prb_read_valid+0x383/0x920 kernel/printk/printk_ringbuffer.c:2114 desc_update_last_finalized kernel/printk/printk_ringbuffer.c:1515 [inline] prb_final_commit+0x136/0x1e0 kernel/printk/printk_ringbuffer.c:1782 vprintk_store+0x741/0x860 kernel/printk/printk.c:2352 vprintk_emit+0x178/0x650 kernel/printk/printk.c:2426 vprintk_default+0x26/0x30 kernel/printk/printk.c:2465 vprintk+0x1d/0x30 kernel/printk/printk_safe.c:82 _printk+0x79/0xa0 kernel/printk/printk.c:2475 caif_disconnect_client+0x13d/0x150 net/caif/cfcnfg.c:194 chnl_net_open+0x4c6/0x560 net/caif/chnl_net.c:326 __dev_open+0x2d2/0x530 net/core/dev.c:1629 __dev_change_flags+0x163/0x400 net/core/dev.c:9366 netif_change_flags+0x5a/0xd0 net/core/dev.c:9429 do_setlink+0x90e/0x27f0 net/core/rtnetlink.c:3152 rtnl_group_changelink net/core/rtnetlink.c:3783 [inline] __rtnl_newlink net/core/rtnetlink.c:3937 [inline] rtnl_newlink+0xd8b/0x12d0 net/core/rtnetlink.c:4065 rtnetlink_rcv_msg+0x5fb/0x6d0 net/core/rtnetlink.c:6955 netlink_rcv_skb+0x120/0x220 net/netlink/af_netlink.c:2534 rtnetlink_rcv+0x1c/0x30 net/core/rtnetlink.c:6982 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+0x142/0x180 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+0xd0/0x1a0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f value changed: 0x0000000000002d5e -> 0x0000000000004d5e Reported by Kernel Concurrency Sanitizer on: CPU: 1 UID: 0 PID: 28986 Comm: syz.4.8845 Not tainted 6.15.0-rc4-syzkaller-00021-gca91b9500108 #0 PREEMPT(voluntary) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025 ================================================================== A link change request failed with some changes committed already. Interface caif0 may have been left with an inconsistent configuration, please check.