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BUG: KCSAN: data-race in _prb_read_valid / data_alloc

write to 0xffffffff86c76ff8 of 8 bytes by task 20334 on cpu 0:
 data_alloc+0x310/0x390 kernel/printk/printk_ringbuffer.c:1129
 prb_reserve+0x8d7/0xae0 kernel/printk/printk_ringbuffer.c:1724
 vprintk_store+0x54a/0x910 kernel/printk/printk.c:2354
 vprintk_emit+0x1a4/0x600 kernel/printk/printk.c:2455
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2494
 vprintk+0x1d/0x30 kernel/printk/printk_safe.c:82
 _printk+0x79/0xa0 kernel/printk/printk.c:2504
 __netdev_printk+0x310/0x370 net/core/dev.c:12929
 netdev_info+0xa6/0xd0 net/core/dev.c:12976
 __dev_set_promiscuity+0x1fb/0x3f0 net/core/dev.c:9563
 netif_set_promiscuity+0x39/0x90 net/core/dev.c:9598
 dev_set_promiscuity+0xc1/0x170 net/core/dev_api.c:287
 rlb_teach_disabled_mac_on_primary drivers/net/bonding/bond_alb.c:366 [inline]
 rlb_clear_slave+0x2bd/0x3d0 drivers/net/bonding/bond_alb.c:421
 bond_alb_deinit_slave+0x325/0x360 drivers/net/bonding/bond_alb.c:1673
 __bond_release_one+0x539/0x9f0 drivers/net/bonding/bond_main.c:2455
 bond_uninit+0x1b4/0x330 drivers/net/bonding/bond_main.c:5996
 unregister_netdevice_many_notify+0x128a/0x1710 net/core/dev.c:12422
 unregister_netdevice_many+0x19/0x20 net/core/dev.c:12464
 ops_exit_rtnl_list net/core/net_namespace.c:187 [inline]
 ops_undo_list+0x21d/0x420 net/core/net_namespace.c:248
 cleanup_net+0x37c/0x5b0 net/core/net_namespace.c:704
 process_one_work kernel/workqueue.c:3275 [inline]
 process_scheduled_works+0x4de/0x9e0 kernel/workqueue.c:3358
 worker_thread+0x581/0x770 kernel/workqueue.c:3439
 kthread+0x22a/0x280 kernel/kthread.c:467
 ret_from_fork+0x150/0x360 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

read to 0xffffffff86c76ff8 of 16 bytes by task 2990 on cpu 1:
 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/0x950 kernel/printk/printk_ringbuffer.c:2170
 prb_read_valid+0x3c/0x60 kernel/printk/printk_ringbuffer.c:2242
 syslog_print+0x258/0x560 kernel/printk/printk.c:1628
 do_syslog+0x52b/0x7f0 kernel/printk/printk.c:1763
 __do_sys_syslog kernel/printk/printk.c:1855 [inline]
 __se_sys_syslog kernel/printk/printk.c:1853 [inline]
 __x64_sys_syslog+0x41/0x50 kernel/printk/printk.c:1853
 x64_sys_call+0x2b9e/0x3020 arch/x86/include/generated/asm/syscalls_64.h:104
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x12c/0x370 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 2990 Comm: klogd Tainted: G        W           syzkaller #0 PREEMPT(full) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
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