syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 ================================================================== BUG: KCSAN: data-race in data_alloc / prb_reserve write to 0xffffffff86882bb0 of 8 bytes by task 19198 on cpu 1: data_alloc+0x280/0x2e0 kernel/printk/printk_ringbuffer.c:1102 prb_reserve+0x807/0xaf0 kernel/printk/printk_ringbuffer.c:1685 vprintk_store+0x56d/0x860 kernel/printk/printk.c:2299 vprintk_emit+0x10d/0x580 kernel/printk/printk.c:2399 vprintk_default+0x26/0x30 kernel/printk/printk.c:2438 vprintk+0x1d/0x30 kernel/printk/printk_safe.c:82 _printk+0x79/0xa0 kernel/printk/printk.c:2448 __netdev_printk+0x321/0x3e0 net/core/dev.c:12724 netdev_info+0x9b/0xd0 net/core/dev.c:12771 tun_net_xmit+0x4a0/0xa60 drivers/net/tun.c:1024 __netdev_start_xmit include/linux/netdevice.h:5248 [inline] netdev_start_xmit include/linux/netdevice.h:5257 [inline] xmit_one net/core/dev.c:3845 [inline] dev_hard_start_xmit+0x125/0x3e0 net/core/dev.c:3861 sch_direct_xmit+0x192/0x550 net/sched/sch_generic.c:344 __dev_xmit_skb net/core/dev.c:4152 [inline] __dev_queue_xmit+0xe9a/0x2000 net/core/dev.c:4729 dev_queue_xmit include/linux/netdevice.h:3365 [inline] neigh_hh_output include/net/neighbour.h:531 [inline] neigh_output include/net/neighbour.h:545 [inline] ip_finish_output2+0x77f/0x8b0 net/ipv4/ip_output.c:237 __ip_finish_output net/ipv4/ip_output.c:-1 [inline] ip_finish_output+0x114/0x2a0 net/ipv4/ip_output.c:325 NF_HOOK_COND include/linux/netfilter.h:307 [inline] ip_mc_output+0x25d/0x340 net/ipv4/ip_output.c:422 dst_output include/net/dst.h:464 [inline] ip_local_out net/ipv4/ip_output.c:131 [inline] ip_send_skb+0x151/0x160 net/ipv4/ip_output.c:1508 udp_send_skb+0x6e3/0xa40 net/ipv4/udp.c:1195 udp_sendmsg+0x1050/0x13c0 net/ipv4/udp.c:1484 inet_sendmsg+0xac/0xd0 net/ipv4/af_inet.c:853 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg+0x102/0x180 net/socket.c:742 ____sys_sendmsg+0x345/0x4e0 net/socket.c:2630 ___sys_sendmsg+0x17b/0x1d0 net/socket.c:2684 __sys_sendmmsg+0x178/0x300 net/socket.c:2773 __do_sys_sendmmsg net/socket.c:2800 [inline] __se_sys_sendmmsg net/socket.c:2797 [inline] __x64_sys_sendmmsg+0x57/0x70 net/socket.c:2797 x64_sys_call+0x1c4a/0x3000 arch/x86/include/generated/asm/syscalls_64.h:308 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 0xffffffff86882bb0 of 8 bytes by task 19120 on cpu 0: desc_read kernel/printk/printk_ringbuffer.c:479 [inline] desc_push_tail kernel/printk/printk_ringbuffer.c:775 [inline] desc_reserve kernel/printk/printk_ringbuffer.c:921 [inline] prb_reserve+0x220/0xaf0 kernel/printk/printk_ringbuffer.c:1635 vprintk_store+0x56d/0x860 kernel/printk/printk.c:2299 vprintk_emit+0x10d/0x580 kernel/printk/printk.c:2399 vprintk_default+0x26/0x30 kernel/printk/printk.c:2438 vprintk+0x1d/0x30 kernel/printk/printk_safe.c:82 _printk+0x79/0xa0 kernel/printk/printk.c:2448 __netdev_printk+0x321/0x3e0 net/core/dev.c:12724 netdev_info+0x9b/0xd0 net/core/dev.c:12771 tun_net_xmit+0x4a0/0xa60 drivers/net/tun.c:1024 __netdev_start_xmit include/linux/netdevice.h:5248 [inline] netdev_start_xmit include/linux/netdevice.h:5257 [inline] xmit_one net/core/dev.c:3845 [inline] dev_hard_start_xmit+0x125/0x3e0 net/core/dev.c:3861 sch_direct_xmit+0x192/0x550 net/sched/sch_generic.c:344 __dev_xmit_skb net/core/dev.c:4152 [inline] __dev_queue_xmit+0xe9a/0x2000 net/core/dev.c:4729 dev_queue_xmit include/linux/netdevice.h:3365 [inline] neigh_hh_output include/net/neighbour.h:531 [inline] neigh_output include/net/neighbour.h:545 [inline] ip_finish_output2+0x77f/0x8b0 net/ipv4/ip_output.c:237 __ip_finish_output net/ipv4/ip_output.c:-1 [inline] ip_finish_output+0x114/0x2a0 net/ipv4/ip_output.c:325 NF_HOOK_COND include/linux/netfilter.h:307 [inline] ip_mc_output+0x25d/0x340 net/ipv4/ip_output.c:422 dst_output include/net/dst.h:464 [inline] ip_local_out net/ipv4/ip_output.c:131 [inline] ip_send_skb+0x151/0x160 net/ipv4/ip_output.c:1508 udp_send_skb+0x6e3/0xa40 net/ipv4/udp.c:1195 udp_sendmsg+0x1050/0x13c0 net/ipv4/udp.c:1484 inet_sendmsg+0xac/0xd0 net/ipv4/af_inet.c:853 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg+0x102/0x180 net/socket.c:742 ____sys_sendmsg+0x345/0x4e0 net/socket.c:2630 ___sys_sendmsg+0x17b/0x1d0 net/socket.c:2684 __sys_sendmmsg+0x178/0x300 net/socket.c:2773 __do_sys_sendmmsg net/socket.c:2800 [inline] __se_sys_sendmmsg net/socket.c:2797 [inline] __x64_sys_sendmmsg+0x57/0x70 net/socket.c:2797 x64_sys_call+0x1c4a/0x3000 arch/x86/include/generated/asm/syscalls_64.h:308 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 value changed: 0x00000000002284b8 -> 0x000000000028c2b0 Reported by Kernel Concurrency Sanitizer on: CPU: 0 UID: 0 PID: 19120 Comm: syz.8.18085 Tainted: G W syzkaller #0 PREEMPT(voluntary) Tainted: [W]=WARN Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 ================================================================== syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42 syz_tun: tun_net_xmit 42