SELinux: syz.4.15369 (30158) wrote to /sys/fs/selinux/user! This will not be supported in the future; please update your userspace.
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BUG: KCSAN: data-race in data_push_tail / string

write to 0xffffffff88e60210 of 1 bytes by task 19926 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
 br_set_state+0x28c/0x390 net/bridge/br_stp.c:57
 br_init_port net/bridge/br_stp_if.c:39 [inline]
 br_stp_enable_port+0x5e/0x110 net/bridge/br_stp_if.c:93
 br_port_carrier_check+0x200/0x230 net/bridge/br_if.c:89
 br_device_event+0x3ce/0x5f0 net/bridge/br.c:96
 notifier_call_chain kernel/notifier.c:85 [inline]
 raw_notifier_call_chain+0x6c/0x1b0 kernel/notifier.c:453
 call_netdevice_notifiers_info+0xae/0x100 net/core/dev.c:2229
 netif_state_change+0x16d/0x1f0 net/core/dev.c:1583
 linkwatch_do_dev+0xb9/0xf0 net/core/link_watch.c:186
 __linkwatch_run_queue+0x582/0x850 net/core/link_watch.c:244
 linkwatch_event+0x40/0x50 net/core/link_watch.c:304
 process_one_work kernel/workqueue.c:3263 [inline]
 process_scheduled_works+0x4cb/0x9d0 kernel/workqueue.c:3346
 worker_thread+0x582/0x770 kernel/workqueue.c:3427
 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

read to 0xffffffff88e60210 of 8 bytes by task 30158 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
 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
 sel_write_user+0x288/0x450 security/selinux/selinuxfs.c:1072
 selinux_transaction_write+0xc3/0x110 security/selinux/selinuxfs.c:835
 vfs_write+0x269/0x960 fs/read_write.c:684
 ksys_write+0xda/0x1a0 fs/read_write.c:738
 __do_sys_write fs/read_write.c:749 [inline]
 __se_sys_write fs/read_write.c:746 [inline]
 __x64_sys_write+0x40/0x50 fs/read_write.c:746
 x64_sys_call+0x2802/0x3000 arch/x86/include/generated/asm/syscalls_64.h:2
 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: 0x000000010000405a -> 0x28322074726f7020

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 30158 Comm: syz.4.15369 Tainted: G        W           syzkaller #0 PREEMPT(voluntary) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
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