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BUG: KCSAN: data-race in _prb_read_valid / prb_reserve

write to 0xffffffff868f3d50 of 88 bytes by task 20997 on cpu 1:
 prb_reserve+0x76a/0xb60 kernel/printk/printk_ringbuffer.c:1690
 vprintk_store+0x56d/0x860 kernel/printk/printk.c:2302
 vprintk_emit+0x15a/0x610 kernel/printk/printk.c:2402
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2441
 vprintk+0x1d/0x30 kernel/printk/printk_safe.c:82
 _printk+0x79/0xa0 kernel/printk/printk.c:2451
 __netdev_printk+0x310/0x370 net/core/dev.c:12909
 netdev_info+0x9b/0xd0 net/core/dev.c:12956
 team_port_del+0x667/0x6f0 drivers/net/team/team_core.c:1335
 team_del_slave drivers/net/team/team_core.c:1936 [inline]
 team_device_event+0x13c/0x380 drivers/net/team/team_core.c:2929
 notifier_call_chain kernel/notifier.c:85 [inline]
 raw_notifier_call_chain+0x6f/0x1b0 kernel/notifier.c:453
 call_netdevice_notifiers_info net/core/dev.c:2230 [inline]
 call_netdevice_notifiers_extack net/core/dev.c:2268 [inline]
 call_netdevice_notifiers net/core/dev.c:2282 [inline]
 unregister_netdevice_many_notify+0xea0/0x16d0 net/core/dev.c:12381
 unregister_netdevice_many net/core/dev.c:12444 [inline]
 default_device_exit_batch+0x5cb/0x620 net/core/dev.c:13036
 ops_exit_list net/core/net_namespace.c:205 [inline]
 ops_undo_list+0x2c0/0x410 net/core/net_namespace.c:252
 cleanup_net+0x2f4/0x520 net/core/net_namespace.c:696
 process_one_work kernel/workqueue.c:3257 [inline]
 process_scheduled_works+0x4ce/0x9d0 kernel/workqueue.c:3340
 worker_thread+0x582/0x770 kernel/workqueue.c:3421
 kthread+0x489/0x510 kernel/kthread.c:463
 ret_from_fork+0x149/0x290 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246

read to 0xffffffff868f3d50 of 8 bytes by task 32682 on cpu 0:
 desc_read kernel/printk/printk_ringbuffer.c:500 [inline]
 desc_read_finalized_seq kernel/printk/printk_ringbuffer.c:1931 [inline]
 prb_read kernel/printk/printk_ringbuffer.c:1979 [inline]
 _prb_read_valid+0x1c4/0x920 kernel/printk/printk_ringbuffer.c:2170
 prb_read_valid+0x3c/0x60 kernel/printk/printk_ringbuffer.c:2242
 __console_flush_and_unlock kernel/printk/printk.c:3338 [inline]
 console_unlock+0x164/0x2e0 kernel/printk/printk.c:3359
 class_console_lock_destructor include/linux/console.h:737 [inline]
 do_con_write+0x28df/0x2940 drivers/tty/vt/vt.c:3243
 con_write+0x24/0x40 drivers/tty/vt/vt.c:3565
 process_output_block drivers/tty/n_tty.c:557 [inline]
 n_tty_write+0x82d/0xbf0 drivers/tty/n_tty.c:2366
 iterate_tty_write drivers/tty/tty_io.c:1006 [inline]
 file_tty_write+0x378/0x690 drivers/tty/tty_io.c:1081
 tty_write+0x25/0x30 drivers/tty/tty_io.c:1102
 do_iter_readv_writev+0x4a1/0x540 fs/read_write.c:-1
 vfs_writev+0x2df/0x8b0 fs/read_write.c:1057
 do_writev+0xe7/0x210 fs/read_write.c:1103
 __do_sys_writev fs/read_write.c:1171 [inline]
 __se_sys_writev fs/read_write.c:1168 [inline]
 __x64_sys_writev+0x45/0x50 fs/read_write.c:1168
 x64_sys_call+0x1ba5/0x3000 arch/x86/include/generated/asm/syscalls_64.h:21
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd8/0x2c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00000000000030aa -> 0x00000000000050aa

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 32682 Comm: syz.2.10460 Not tainted syzkaller #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
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