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BUG: KCSAN: data-race in _prb_read_valid / data_alloc

write to 0xffffffff86880af8 of 8 bytes by task 14194 on cpu 1:
 data_alloc+0x310/0x390 kernel/printk/printk_ringbuffer.c:1129
 prb_reserve+0x964/0xb60 kernel/printk/printk_ringbuffer.c:1724
 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
 __dev_set_promiscuity+0x1fb/0x3f0 net/core/dev.c:9546
 netif_set_promiscuity+0x39/0x90 net/core/dev.c:9581
 dev_set_promiscuity+0xc1/0x170 net/core/dev_api.c:287
 bond_set_promiscuity drivers/net/bonding/bond_main.c:849 [inline]
 bond_change_rx_flags+0x15d/0x340 drivers/net/bonding/bond_main.c:4573
 dev_change_rx_flags net/core/dev.c:9517 [inline]
 __dev_set_promiscuity+0x373/0x3f0 net/core/dev.c:9561
 netif_set_promiscuity+0x39/0x90 net/core/dev.c:9581
 dev_set_promiscuity+0xc1/0x170 net/core/dev_api.c:287
 macvlan_stop+0x198/0x260 drivers/net/macvlan.c:707
 __dev_close_many+0x23e/0x440 net/core/dev.c:1756
 netif_close_many+0x101/0x2d0 net/core/dev.c:1781
 unregister_netdevice_many_notify+0x4f4/0x16d0 net/core/dev.c:12351
 unregister_netdevice_many+0x19/0x20 net/core/dev.c:12444
 macvlan_device_event+0x4b0/0x4f0 drivers/net/macvlan.c:1834
 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+0x19/0x20 net/core/dev.c:12444
 ops_exit_rtnl_list net/core/net_namespace.c:187 [inline]
 ops_undo_list+0x213/0x410 net/core/net_namespace.c:248
 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 0xffffffff86880af8 of 16 bytes by task 2994 on cpu 0:
 desc_read kernel/printk/printk_ringbuffer.c:496 [inline]
 desc_read_finalized_seq kernel/printk/printk_ringbuffer.c:1931 [inline]
 prb_read kernel/printk/printk_ringbuffer.c:1979 [inline]
 _prb_read_valid+0x1bc/0x920 kernel/printk/printk_ringbuffer.c:2170
 prb_read_valid+0x3c/0x60 kernel/printk/printk_ringbuffer.c:2242
 syslog_print+0x23a/0x540 kernel/printk/printk.c:1626
 do_syslog+0x52b/0x7e0 kernel/printk/printk.c:1761
 __do_sys_syslog kernel/printk/printk.c:1853 [inline]
 __se_sys_syslog kernel/printk/printk.c:1851 [inline]
 __x64_sys_syslog+0x41/0x50 kernel/printk/printk.c:1851
 x64_sys_call+0x27ce/0x3000 arch/x86/include/generated/asm/syscalls_64.h:104
 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

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 2994 Comm: klogd Not tainted syzkaller #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
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