syzbot

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BUG: KCSAN: data-race in _prb_read_valid / prb_reserve

write to 0xffffffff85b279e8 of 8 bytes by task 17193 on cpu 0:
 prb_reserve+0x733/0xbd0
 vprintk_store+0x51c/0xb50 kernel/printk/printk.c:2326
 vprintk_emit+0xcc/0x4e0 kernel/printk/printk.c:2382
 dev_vprintk_emit+0x1c9/0x1ed drivers/base/core.c:4604
 dev_printk_emit+0x7e/0xa2 drivers/base/core.c:4615
 __netdev_printk+0x245/0x2c0 net/core/dev.c:11200
 netdev_warn+0x9d/0xc1 net/core/dev.c:11253
 ieee802154_subif_start_xmit+0x91/0xa0 net/mac802154/tx.c:125
 __netdev_start_xmit include/linux/netdevice.h:4805 [inline]
 netdev_start_xmit include/linux/netdevice.h:4819 [inline]
 xmit_one+0xc0/0x2a0 net/core/dev.c:3588
 dev_hard_start_xmit+0x72/0x120 net/core/dev.c:3604
 sch_direct_xmit+0x1ac/0x580 net/sched/sch_generic.c:342
 __dev_xmit_skb+0x808/0xdb0 net/core/dev.c:3815
 __dev_queue_xmit+0x59f/0xfe0 net/core/dev.c:4219
 dev_queue_xmit include/linux/netdevice.h:2994 [inline]
 raw_sendmsg+0x2ad/0x420 net/ieee802154/socket.c:294
 ieee802154_sock_sendmsg+0x47/0x50 net/ieee802154/socket.c:96
 sock_sendmsg_nosec net/socket.c:714 [inline]
 sock_sendmsg net/socket.c:734 [inline]
 ____sys_sendmsg+0x38f/0x500 net/socket.c:2492
 ___sys_sendmsg net/socket.c:2546 [inline]
 __sys_sendmmsg+0x27c/0x4a0 net/socket.c:2632
 __do_sys_sendmmsg net/socket.c:2661 [inline]
 __se_sys_sendmmsg net/socket.c:2658 [inline]
 __x64_sys_sendmmsg+0x53/0x60 net/socket.c:2658
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x46/0xb0

read to 0xffffffff85b279e8 of 8 bytes by task 14 on cpu 1:
 desc_read kernel/printk/printk_ringbuffer.c:482 [inline]
 prb_first_seq kernel/printk/printk_ringbuffer.c:1846 [inline]
 _prb_read_valid+0x2e3/0x950 kernel/printk/printk_ringbuffer.c:1892
 prb_read_valid+0x39/0x60 kernel/printk/printk_ringbuffer.c:1940
 __console_emit_next_record+0xca/0x690 kernel/printk/printk.c:2869
 console_emit_next_record kernel/printk/printk.c:3721 [inline]
 printk_kthread_func+0x862/0xb60 kernel/printk/printk.c:3837
 kthread+0x1a9/0x1e0 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30

value changed: 0x0000000000001cc5 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 14 Comm: pr/ttyS0 Not tainted 5.18.0-syzkaller-10037-g7e284070abe5-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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