sysfs: cannot create duplicate filename '/devices/virtual/net/vcan10000000000'
==================================================================
BUG: KCSAN: data-race in data_push_tail / vsnprintf

write to 0xffffffff86ec22ec of 1 bytes by task 28684 on cpu 1:
 vsnprintf+0xdd0/0xe20
 va_format lib/vsprintf.c:1683 [inline]
 pointer+0x8a1/0xd10 lib/vsprintf.c:2450
 vsnprintf+0x861/0xe20 lib/vsprintf.c:2823
 vscnprintf+0x42/0x80 lib/vsprintf.c:2925
 printk_sprint+0x30/0x2d0 kernel/printk/printk.c:2124
 vprintk_store+0x56f/0x800 kernel/printk/printk.c:2238
 vprintk_emit+0xd0/0x5d0 kernel/printk/printk.c:2284
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2318
 vprintk+0x71/0x80 kernel/printk/printk_safe.c:45
 _printk+0x7a/0xa0 kernel/printk/printk.c:2328
 __ext4_msg+0x18a/0x1a0 fs/ext4/super.c:1006
 ext4_setup_super+0x1e0/0x560
 __ext4_fill_super fs/ext4/super.c:5502 [inline]
 ext4_fill_super+0x3051/0x39a0 fs/ext4/super.c:5711
 get_tree_bdev+0x272/0x300 fs/super.c:1598
 ext4_get_tree+0x1c/0x20 fs/ext4/super.c:5743
 vfs_get_tree+0x51/0x1b0 fs/super.c:1771
 do_new_mount+0x203/0x660 fs/namespace.c:3337
 path_mount+0x496/0xb30 fs/namespace.c:3664
 do_mount fs/namespace.c:3677 [inline]
 __do_sys_mount fs/namespace.c:3886 [inline]
 __se_sys_mount+0x27f/0x2d0 fs/namespace.c:3863
 __x64_sys_mount+0x67/0x80 fs/namespace.c:3863
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x44/0x110 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

read to 0xffffffff86ec22e8 of 8 bytes by task 28702 on cpu 0:
 data_make_reusable kernel/printk/printk_ringbuffer.c:590 [inline]
 data_push_tail+0x102/0x430 kernel/printk/printk_ringbuffer.c:675
 data_alloc+0xbe/0x2c0 kernel/printk/printk_ringbuffer.c:1046
 prb_reserve+0x893/0xbc0 kernel/printk/printk_ringbuffer.c:1555
 vprintk_store+0x53e/0x800 kernel/printk/printk.c:2228
 vprintk_emit+0xd0/0x5d0 kernel/printk/printk.c:2284
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2318
 vprintk+0x71/0x80 kernel/printk/printk_safe.c:45
 _printk+0x7a/0xa0 kernel/printk/printk.c:2328
 sysfs_warn_dup fs/sysfs/dir.c:29 [inline]
 sysfs_create_dir_ns+0x1a3/0x1d0 fs/sysfs/dir.c:63
 create_dir lib/kobject.c:73 [inline]
 kobject_add_internal+0x3eb/0x730 lib/kobject.c:238
 kobject_add_varg lib/kobject.c:372 [inline]
 kobject_add+0xdc/0x150 lib/kobject.c:424
 device_add+0x2f8/0x8b0 drivers/base/core.c:3563
 netdev_register_kobject+0xfc/0x230 net/core/net-sysfs.c:2044
 register_netdevice+0x65b/0xb20 net/core/dev.c:10164
 rtnl_newlink_create net/core/rtnetlink.c:3523 [inline]
 __rtnl_newlink net/core/rtnetlink.c:3741 [inline]
 rtnl_newlink+0x103d/0x1670 net/core/rtnetlink.c:3754
 rtnetlink_rcv_msg+0x807/0x8c0 net/core/rtnetlink.c:6558
 netlink_rcv_skb+0x126/0x220 net/netlink/af_netlink.c:2545
 rtnetlink_rcv+0x1c/0x20 net/core/rtnetlink.c:6576
 netlink_unicast_kernel net/netlink/af_netlink.c:1342 [inline]
 netlink_unicast+0x589/0x650 net/netlink/af_netlink.c:1368
 netlink_sendmsg+0x66e/0x770 net/netlink/af_netlink.c:1910
 sock_sendmsg_nosec net/socket.c:730 [inline]
 __sock_sendmsg net/socket.c:745 [inline]
 ____sys_sendmsg+0x37c/0x4d0 net/socket.c:2588
 ___sys_sendmsg net/socket.c:2642 [inline]
 __sys_sendmsg+0x1e9/0x270 net/socket.c:2671
 __do_sys_sendmsg net/socket.c:2680 [inline]
 __se_sys_sendmsg net/socket.c:2678 [inline]
 __x64_sys_sendmsg+0x46/0x50 net/socket.c:2678
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x44/0x110 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

value changed: 0x00000001000047cb -> 0x000000016465646e

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 28702 Comm: syz-executor.4 Not tainted 6.6.0-syzkaller-14500-g1c41041124bd #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/09/2023
==================================================================
CPU: 0 PID: 28702 Comm: syz-executor.4 Not tainted 6.6.0-syzkaller-14500-g1c41041124bd #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/09/2023
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xda/0x130 lib/dump_stack.c:106
 dump_stack+0x15/0x20 lib/dump_stack.c:113
 sysfs_warn_dup fs/sysfs/dir.c:30 [inline]
 sysfs_create_dir_ns+0x1a8/0x1d0 fs/sysfs/dir.c:63
 create_dir lib/kobject.c:73 [inline]
 kobject_add_internal+0x3eb/0x730 lib/kobject.c:238
 kobject_add_varg lib/kobject.c:372 [inline]
 kobject_add+0xdc/0x150 lib/kobject.c:424
 device_add+0x2f8/0x8b0 drivers/base/core.c:3563
 netdev_register_kobject+0xfc/0x230 net/core/net-sysfs.c:2044
 register_netdevice+0x65b/0xb20 net/core/dev.c:10164
 rtnl_newlink_create net/core/rtnetlink.c:3523 [inline]
 __rtnl_newlink net/core/rtnetlink.c:3741 [inline]
 rtnl_newlink+0x103d/0x1670 net/core/rtnetlink.c:3754
 rtnetlink_rcv_msg+0x807/0x8c0 net/core/rtnetlink.c:6558
 netlink_rcv_skb+0x126/0x220 net/netlink/af_netlink.c:2545
 rtnetlink_rcv+0x1c/0x20 net/core/rtnetlink.c:6576
 netlink_unicast_kernel net/netlink/af_netlink.c:1342 [inline]
 netlink_unicast+0x589/0x650 net/netlink/af_netlink.c:1368
 netlink_sendmsg+0x66e/0x770 net/netlink/af_netlink.c:1910
 sock_sendmsg_nosec net/socket.c:730 [inline]
 __sock_sendmsg net/socket.c:745 [inline]
 ____sys_sendmsg+0x37c/0x4d0 net/socket.c:2588
 ___sys_sendmsg net/socket.c:2642 [inline]
 __sys_sendmsg+0x1e9/0x270 net/socket.c:2671
 __do_sys_sendmsg net/socket.c:2680 [inline]
 __se_sys_sendmsg net/socket.c:2678 [inline]
 __x64_sys_sendmsg+0x46/0x50 net/socket.c:2678
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x44/0x110 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x63/0x6b
RIP: 0033:0x7f6c4c1d3ae9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f6c4b5560c8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f6c4c2f2f80 RCX: 00007f6c4c1d3ae9
RDX: 0000000000000000 RSI: 0000000020000300 RDI: 0000000000000004
RBP: 00007f6c4c21f47a R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007f6c4c2f2f80 R15: 00007ffc1a45b3b8
 </TASK>
kobject: kobject_add_internal failed for vcan10000000000 with -EEXIST, don't try to register things with the same name in the same directory.
syz-executor.4 (28702) used greatest stack depth: 8952 bytes left