netdevsim netdevsim6 eth2: set [1, 0] type 2 family 0 port 6081 - 0
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BUG: KCSAN: data-race in data_push_tail / string

write to 0xffffffff88e28450 of 1 bytes by task 10219 on cpu 0:
 string_nocheck lib/vsprintf.c:657 [inline]
 string+0x187/0x220 lib/vsprintf.c:735
 vsnprintf+0x532/0x890 lib/vsprintf.c:2926
 vscnprintf+0x41/0x90 lib/vsprintf.c:2991
 printk_sprint+0x30/0x2d0 kernel/printk/printk.c:2216
 vprintk_store+0x599/0x860 kernel/printk/printk.c:2336
 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
 dump_stack_print_info+0xee/0x1b0 lib/dump_stack.c:57
 __dump_stack+0x11/0x30 lib/dump_stack.c:93
 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:4144 [inline]
 slab_alloc_node mm/slub.c:4220 [inline]
 kmem_cache_alloc_noprof+0x50/0x310 mm/slub.c:4247
 audit_buffer_alloc kernel/audit.c:1791 [inline]
 audit_log_start+0x365/0x6c0 kernel/audit.c:1913
 audit_seccomp+0x48/0x100 kernel/auditsc.c:3001
 seccomp_log kernel/seccomp.c:1033 [inline]
 __seccomp_filter+0x69d/0x10d0 kernel/seccomp.c:1328
 __secure_computing+0x82/0x150 kernel/seccomp.c:1388
 syscall_trace_enter+0xcf/0x1e0 kernel/entry/syscall-common.c:44
 syscall_enter_from_user_mode_work include/linux/entry-common.h:95 [inline]
 syscall_enter_from_user_mode include/linux/entry-common.h:125 [inline]
 do_syscall_64+0xac/0x200 arch/x86/entry/syscall_64.c:90
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffffffff88e28450 of 8 bytes by task 3804 on cpu 1:
 data_make_reusable kernel/printk/printk_ringbuffer.c:594 [inline]
 data_push_tail+0xfd/0x420 kernel/printk/printk_ringbuffer.c:679
 data_alloc+0xbf/0x2b0 kernel/printk/printk_ringbuffer.c:1054
 prb_reserve+0x808/0xaf0 kernel/printk/printk_ringbuffer.c:1669
 vprintk_store+0x56d/0x860 kernel/printk/printk.c:2326
 vprintk_emit+0x178/0x650 kernel/printk/printk.c:2426
 dev_vprintk_emit+0x242/0x2a0 drivers/base/core.c:4914
 dev_printk_emit+0x84/0xb0 drivers/base/core.c:4925
 __netdev_printk+0x35c/0x3e0 net/core/dev.c:12598
 netdev_info+0x9b/0xd0 net/core/dev.c:12653
 nsim_udp_tunnel_set_port+0x13b/0x160 drivers/net/netdevsim/udp_tunnels.c:31
 udp_tunnel_nic_device_sync_one net/ipv4/udp_tunnel_nic.c:-1 [inline]
 udp_tunnel_nic_device_sync_by_port net/ipv4/udp_tunnel_nic.c:249 [inline]
 __udp_tunnel_nic_device_sync+0x564/0x9c0 net/ipv4/udp_tunnel_nic.c:292
 udp_tunnel_nic_device_sync_work+0x5d/0x5f0 net/ipv4/udp_tunnel_nic.c:740
 process_one_work kernel/workqueue.c:3236 [inline]
 process_scheduled_works+0x4cb/0x9d0 kernel/workqueue.c:3319
 worker_thread+0x582/0x770 kernel/workqueue.c:3400
 kthread+0x489/0x510 kernel/kthread.c:463
 ret_from_fork+0x11f/0x1b0 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

value changed: 0x00000000ffffef50 -> 0x617420746f4e2031

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 3804 Comm: kworker/u8:11 Not tainted syzkaller #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Workqueue: udp_tunnel_nic udp_tunnel_nic_device_sync_work
==================================================================
netdevsim netdevsim6 eth3: set [1, 0] type 2 family 0 port 6081 - 0