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BUG: KCSAN: data-race in _prb_read_valid / prb_reserve

write to 0xffffffff868b04b0 of 8 bytes by task 28012 on cpu 1:
 prb_reserve+0x750/0xb80 kernel/printk/printk_ringbuffer.c:-1
 vprintk_store+0x552/0x860 kernel/printk/printk.c:2326
 vprintk_emit+0x1a0/0x6c0 kernel/printk/printk.c:2426
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2465
 vprintk+0x1d/0x30 kernel/printk/printk_safe.c:82
 _printk+0x7f/0xb0 kernel/printk/printk.c:2475
 siw_device_register drivers/infiniband/sw/siw/siw_main.c:73 [inline]
 siw_newlink+0x6b6/0x6d0 drivers/infiniband/sw/siw/siw_main.c:430
 nldev_newlink+0x36c/0x3f0 drivers/infiniband/core/nldev.c:1796
 rdma_nl_rcv_msg drivers/infiniband/core/netlink.c:195 [inline]
 rdma_nl_rcv_skb drivers/infiniband/core/netlink.c:239 [inline]
 rdma_nl_rcv+0x48a/0x5b0 drivers/infiniband/core/netlink.c:259
 netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline]
 netlink_unicast+0x605/0x6c0 net/netlink/af_netlink.c:1339
 netlink_sendmsg+0x609/0x720 net/netlink/af_netlink.c:1883
 sock_sendmsg_nosec net/socket.c:712 [inline]
 __sock_sendmsg+0x140/0x180 net/socket.c:727
 ____sys_sendmsg+0x350/0x4e0 net/socket.c:2566
 ___sys_sendmsg net/socket.c:2620 [inline]
 __sys_sendmsg+0x1a0/0x240 net/socket.c:2652
 __do_sys_sendmsg net/socket.c:2657 [inline]
 __se_sys_sendmsg net/socket.c:2655 [inline]
 __x64_sys_sendmsg+0x46/0x50 net/socket.c:2655
 x64_sys_call+0x26f3/0x2e10 arch/x86/include/generated/asm/syscalls_64.h:47
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffffffff868b04b0 of 8 bytes by task 28015 on cpu 0:
 desc_read kernel/printk/printk_ringbuffer.c:486 [inline]
 prb_first_seq kernel/printk/printk_ringbuffer.c:1957 [inline]
 _prb_read_valid+0x471/0x710 kernel/printk/printk_ringbuffer.c:2114
 prb_read_valid+0x42/0x70 kernel/printk/printk_ringbuffer.c:2185
 syslog_print+0xf2/0x540 kernel/printk/printk.c:1633
 do_syslog+0x3ae/0x810 kernel/printk/printk.c:1785
 __do_sys_syslog kernel/printk/printk.c:1877 [inline]
 __se_sys_syslog kernel/printk/printk.c:1875 [inline]
 __x64_sys_syslog+0x43/0x50 kernel/printk/printk.c:1875
 x64_sys_call+0x2b8f/0x2e10 arch/x86/include/generated/asm/syscalls_64.h:104
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x000000000000241e -> 0x000000000000441e

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 28015 Comm: syz.5.9104 Not tainted 6.14.0-syzkaller-13389-ga52a3c18cdf3 #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
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