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BUG: KCSAN: data-race in _prb_read_valid / prb_reserve

write to 0xffffffff86d06d38 of 88 bytes by task 17121 on cpu 1:
 prb_reserve+0x6e0/0xad0 kernel/printk/printk_ringbuffer.c:1693
 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:12946
 netdev_info+0xa6/0xd0 net/core/dev.c:12993
 __dev_set_promiscuity+0x1ee/0x3d0 net/core/dev.c:9615
 __dev_set_rx_mode+0x321/0x390 net/core/dev_addr_lists.c:1383
 dev_uc_del+0x144/0x160 net/core/dev_addr_lists.c:852
 macvlan_stop+0x1b3/0x260 drivers/net/macvlan.c:723
 __dev_close_many+0x250/0x450 net/core/dev.c:1776
 netif_close_many+0x101/0x2d0 net/core/dev.c:1801
 unregister_netdevice_many_notify+0x509/0x1650 net/core/dev.c:12388
 unregister_netdevice_many net/core/dev.c:12481 [inline]
 default_device_exit_batch+0x5e6/0x640 net/core/dev.c:13073
 ops_exit_list net/core/net_namespace.c:205 [inline]
 ops_undo_list+0x2ca/0x420 net/core/net_namespace.c:252
 cleanup_net+0x37c/0x5b0 net/core/net_namespace.c:702
 process_one_work kernel/workqueue.c:3302 [inline]
 process_scheduled_works+0x4f0/0x9c0 kernel/workqueue.c:3385
 worker_thread+0x58a/0x780 kernel/workqueue.c:3466
 kthread+0x22a/0x280 kernel/kthread.c:436
 ret_from_fork+0x146/0x330 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

read to 0xffffffff86d06d38 of 8 bytes by task 2973 on cpu 0:
 desc_read kernel/printk/printk_ringbuffer.c:500 [inline]
 desc_read_finalized_seq kernel/printk/printk_ringbuffer.c:1934 [inline]
 prb_read kernel/printk/printk_ringbuffer.c:1982 [inline]
 _prb_read_valid+0x1be/0x950 kernel/printk/printk_ringbuffer.c:2173
 prb_read_valid+0x3c/0x60 kernel/printk/printk_ringbuffer.c:2245
 syslog_print+0x164/0x560 kernel/printk/printk.c:1611
 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/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00000000000034d3 -> 0x00000000000054d3

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 2973 Comm: klogd Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
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