syzbot

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BUG: KCSAN: data-race in _prb_read_valid / prb_reserve

write to 0xffffffff86b1c5e0 of 88 bytes by task 17505 on cpu 0:
 prb_reserve+0x6e6/0xae0 kernel/printk/printk_ringbuffer.c:1690
 vprintk_store+0x54a/0x910 kernel/printk/printk.c:2302
 vprintk_emit+0x1a4/0x600 kernel/printk/printk.c:2402
 dev_vprintk_emit+0x242/0x2a0 drivers/base/core.c:4914
 dev_printk_emit+0x84/0xb0 drivers/base/core.c:4925
 __dev_printk+0xf3/0x110 drivers/base/core.c:4937
 _dev_info+0xa6/0xd0 drivers/base/core.c:4983
 attach_store+0x495/0x680 drivers/usb/usbip/vhci_sysfs.c:416
 dev_attr_store+0x4a/0x70 drivers/base/core.c:2437
 sysfs_kf_write+0xfe/0x120 fs/sysfs/file.c:142
 kernfs_fop_write_iter+0x1eb/0x300 fs/kernfs/file.c:352
 new_sync_write fs/read_write.c:593 [inline]
 vfs_write+0x5a6/0x9f0 fs/read_write.c:686
 ksys_write+0xdc/0x1a0 fs/read_write.c:738
 __do_sys_write fs/read_write.c:749 [inline]
 __se_sys_write fs/read_write.c:746 [inline]
 __x64_sys_write+0x40/0x50 fs/read_write.c:746
 x64_sys_call+0x2847/0x3000 arch/x86/include/generated/asm/syscalls_64.h:2
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xc0/0x2a0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffffffff86b1c5e0 of 8 bytes by task 17499 on cpu 1:
 desc_read kernel/printk/printk_ringbuffer.c:500 [inline]
 desc_read_finalized_seq kernel/printk/printk_ringbuffer.c:1931 [inline]
 prb_read kernel/printk/printk_ringbuffer.c:1979 [inline]
 _prb_read_valid+0x1c4/0x950 kernel/printk/printk_ringbuffer.c:2170
 prb_read_valid+0x3c/0x60 kernel/printk/printk_ringbuffer.c:2242
 __console_flush_and_unlock kernel/printk/printk.c:3338 [inline]
 console_unlock+0x146/0x280 kernel/printk/printk.c:3359
 vprintk_emit+0x3e4/0x600 kernel/printk/printk.c:2426
 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
 chnl_net_open+0x4eb/0x550 net/caif/chnl_net.c:-1
 __dev_open+0x321/0x560 net/core/dev.c:1696
 __dev_change_flags+0x13e/0x400 net/core/dev.c:9749
 netif_change_flags+0x5a/0xd0 net/core/dev.c:9812
 do_setlink+0x905/0x2940 net/core/rtnetlink.c:3158
 rtnl_group_changelink net/core/rtnetlink.c:3790 [inline]
 __rtnl_newlink net/core/rtnetlink.c:3944 [inline]
 rtnl_newlink+0xdb5/0x1370 net/core/rtnetlink.c:4072
 rtnetlink_rcv_msg+0x64b/0x720 net/core/rtnetlink.c:6958
 netlink_rcv_skb+0x123/0x220 net/netlink/af_netlink.c:2550
 rtnetlink_rcv+0x1c/0x30 net/core/rtnetlink.c:6985
 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
 netlink_unicast+0x5c0/0x690 net/netlink/af_netlink.c:1344
 netlink_sendmsg+0x5c8/0x6f0 net/netlink/af_netlink.c:1894
 sock_sendmsg_nosec net/socket.c:727 [inline]
 __sock_sendmsg net/socket.c:742 [inline]
 ____sys_sendmsg+0x5af/0x600 net/socket.c:2592
 ___sys_sendmsg+0x195/0x1e0 net/socket.c:2646
 __sys_sendmsg net/socket.c:2678 [inline]
 __do_sys_sendmsg net/socket.c:2683 [inline]
 __se_sys_sendmsg net/socket.c:2681 [inline]
 __x64_sys_sendmsg+0xd4/0x160 net/socket.c:2681
 x64_sys_call+0x17ba/0x3000 arch/x86/include/generated/asm/syscalls_64.h:47
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xc0/0x2a0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x0000000000003808 -> 0x0000000000005808

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 17499 Comm: syz.6.13074 Tainted: G        W           syzkaller #0 PREEMPT(voluntary) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
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A link change request failed with some changes committed already. Interface caif0 may have been left with an inconsistent configuration, please check.