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 RIP: 0033:0x7f67ff2deec9 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 ================================================================== BUG: KCSAN: data-race in data_alloc / data_push_tail write to 0xffffffff88e44eb0 of 8 bytes by task 8162 on cpu 0: data_alloc+0x1d5/0x2e0 kernel/printk/printk_ringbuffer.c:1088 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 ip_vs_scheduler_err+0x190/0x1a0 net/netfilter/ipvs/ip_vs_sched.c:-1 ip_vs_sh_schedule+0x4ef/0x5b0 net/netfilter/ipvs/ip_vs_sh.c:332 ip_vs_schedule+0x5b4/0xe20 net/netfilter/ipvs/ip_vs_core.c:528 udp_conn_schedule+0x230/0x3b0 net/netfilter/ipvs/ip_vs_proto_udp.c:78 ip_vs_try_to_schedule net/netfilter/ipvs/ip_vs_core.c:1479 [inline] ip_vs_in_hook+0x5bb/0x1220 net/netfilter/ipvs/ip_vs_core.c:2051 nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline] nf_hook_slow+0x78/0x180 net/netfilter/core.c:623 nf_hook include/linux/netfilter.h:273 [inline] __ip_local_out+0x2cb/0x2f0 net/ipv4/ip_output.c:120 ip_local_out net/ipv4/ip_output.c:129 [inline] ip_send_skb+0x34/0x160 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 0xffffffff88e44eb0 of 8 bytes by task 8161 on cpu 1: data_make_reusable kernel/printk/printk_ringbuffer.c:591 [inline] data_push_tail+0xfd/0x420 kernel/printk/printk_ringbuffer.c:676 data_alloc+0xfb/0x2e0 kernel/printk/printk_ringbuffer.c:1061 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 show_opcodes+0xfe/0x120 arch/x86/kernel/dumpstack.c:121 show_iret_regs+0x12/0x40 arch/x86/kernel/dumpstack.c:147 __show_regs+0x2a/0x440 arch/x86/kernel/process_64.c:77 show_regs_if_on_stack arch/x86/kernel/dumpstack.c:165 [inline] show_trace_log_lvl+0x423/0x560 arch/x86/kernel/dumpstack.c:298 __dump_stack+0x1d/0x30 lib/dump_stack.c:94 dump_stack_lvl+0xe8/0x140 lib/dump_stack.c:120 dump_stack+0x15/0x1b lib/dump_stack.c:129 fail_dump lib/fault-inject.c:73 [inline] should_fail_ex+0x265/0x280 lib/fault-inject.c:174 should_failslab+0x8c/0xb0 mm/failslab.c:46 slab_pre_alloc_hook mm/slub.c:4900 [inline] slab_alloc_node mm/slub.c:5222 [inline] kmem_cache_alloc_noprof+0x50/0x480 mm/slub.c:5253 skb_clone+0x151/0x1f0 net/core/skbuff.c:2050 __netlink_deliver_tap_skb net/netlink/af_netlink.c:300 [inline] __netlink_deliver_tap+0x2c9/0x500 net/netlink/af_netlink.c:325 netlink_deliver_tap net/netlink/af_netlink.c:338 [inline] netlink_deliver_tap_kernel net/netlink/af_netlink.c:347 [inline] netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline] netlink_unicast+0x66b/0x690 net/netlink/af_netlink.c:1346 netlink_sendmsg+0x58b/0x6b0 net/netlink/af_netlink.c:1896 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg+0x145/0x180 net/socket.c:742 ____sys_sendmsg+0x31e/0x4e0 net/socket.c:2630 ___sys_sendmsg+0x17b/0x1d0 net/socket.c:2684 __sys_sendmsg net/socket.c:2716 [inline] __do_sys_sendmsg net/socket.c:2721 [inline] __se_sys_sendmsg net/socket.c:2719 [inline] __x64_sys_sendmsg+0xd4/0x160 net/socket.c:2719 x64_sys_call+0x191e/0x3000 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 value changed: 0x00000000ffffe72a -> 0x00000000fffff360 Reported by Kernel Concurrency Sanitizer on: CPU: 1 UID: 0 PID: 8161 Comm: syz.1.1405 Not tainted syzkaller #0 PREEMPT(voluntary) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 ================================================================== RSP: 002b:00007f67fdd3f038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007f67ff535fa0 RCX: 00007f67ff2deec9 RDX: 0000000000004054 RSI: 00002000000002c0 RDI: 0000000000000003 RBP: 00007f67fdd3f090 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 R13: 00007f67ff536038 R14: 00007f67ff535fa0 R15: 00007fffe10a2078