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BUG: KCSAN: data-race in rwsem_down_write_slowpath / rwsem_down_write_slowpath

write to 0xffffc9000142fb68 of 1 bytes by task 5662 on cpu 0:
 rwsem_try_write_lock kernel/locking/rwsem.c:676 [inline]
 rwsem_down_write_slowpath+0x3eb/0xab0 kernel/locking/rwsem.c:1189
 __down_write_common kernel/locking/rwsem.c:1347 [inline]
 __down_write kernel/locking/rwsem.c:1356 [inline]
 down_write+0xab/0xc0 kernel/locking/rwsem.c:1632
 kernfs_add_one+0x5a/0x290 fs/kernfs/dir.c:825
 __kernfs_create_file+0x145/0x180 fs/kernfs/file.c:1079
 sysfs_add_file_mode_ns+0x132/0x1b0 fs/sysfs/file.c:316
 create_files fs/sysfs/group.c:82 [inline]
 internal_create_group+0x43e/0x9e0 fs/sysfs/group.c:189
 internal_create_groups fs/sysfs/group.c:229 [inline]
 sysfs_create_groups+0x3f/0xf0 fs/sysfs/group.c:255
 device_add_groups drivers/base/core.c:2907 [inline]
 device_add_attrs+0xf2/0x3f0 drivers/base/core.c:2982
 device_add+0x37a/0x790 drivers/base/core.c:3711
 netdev_register_kobject+0x108/0x220 net/core/net-sysfs.c:2337
 register_netdevice+0xaf7/0x11a0 net/core/dev.c:11446
 bond_newlink+0x2f/0xb0 drivers/net/bonding/bond_netlink.c:625
 rtnl_newlink_create+0x1e7/0x650 net/core/rtnetlink.c:3913
 __rtnl_newlink net/core/rtnetlink.c:4044 [inline]
 rtnl_newlink+0x1181/0x1400 net/core/rtnetlink.c:4159
 rtnetlink_rcv_msg+0x64b/0x720 net/core/rtnetlink.c:7076
 netlink_rcv_skb+0x11e/0x220 net/netlink/af_netlink.c:2556
 rtnetlink_rcv+0x1c/0x30 net/core/rtnetlink.c:7103
 netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline]
 netlink_unicast+0x5a7/0x680 net/netlink/af_netlink.c:1345
 netlink_sendmsg+0x5be/0x6f0 net/netlink/af_netlink.c:1900
 sock_sendmsg_nosec net/socket.c:775 [inline]
 __sock_sendmsg net/socket.c:790 [inline]
 ____sys_sendmsg+0x532/0x580 net/socket.c:2684
 ___sys_sendmsg+0x195/0x1e0 net/socket.c:2738
 __sys_sendmsg net/socket.c:2770 [inline]
 __do_sys_sendmsg net/socket.c:2775 [inline]
 __se_sys_sendmsg net/socket.c:2773 [inline]
 __x64_sys_sendmsg+0xd4/0x160 net/socket.c:2773
 x64_sys_call+0x194c/0x3020 arch/x86/include/generated/asm/syscalls_64.h:47
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x136/0x3c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffffc9000142fb68 of 1 bytes by task 3303 on cpu 1:
 rwsem_down_write_slowpath+0x462/0xab0 kernel/locking/rwsem.c:1207
 __down_write_common kernel/locking/rwsem.c:1347 [inline]
 __down_write kernel/locking/rwsem.c:1356 [inline]
 down_write+0xab/0xc0 kernel/locking/rwsem.c:1632
 kernfs_remove_by_name_ns+0x6b/0x110 fs/kernfs/dir.c:1792
 kernfs_remove_by_name include/linux/kernfs.h:644 [inline]
 remove_files fs/sysfs/group.c:28 [inline]
 sysfs_remove_group+0xa5/0x170 fs/sysfs/group.c:328
 sysfs_remove_groups+0x3a/0x80 fs/sysfs/group.c:352
 __kobject_del+0x4b/0x190 lib/kobject.c:595
 kobject_del+0x2e/0x50 lib/kobject.c:627
 ext4_unregister_sysfs+0x84/0xa0 fs/ext4/sysfs.c:654
 ext4_put_super+0x4c/0x7c0 fs/ext4/super.c:1299
 generic_shutdown_super+0xee/0x220 fs/super.c:647
 kill_block_super+0x2a/0x70 fs/super.c:1671
 ext4_kill_sb+0x42/0x80 fs/ext4/super.c:7499
 deactivate_locked_super+0x75/0x1c0 fs/super.c:477
 deactivate_super+0x97/0xa0 fs/super.c:510
 cleanup_mnt+0x2c3/0x340 fs/namespace.c:1317
 __cleanup_mnt+0x19/0x20 fs/namespace.c:1324
 task_work_run+0x130/0x1a0 kernel/task_work.c:233
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 __exit_to_user_mode_loop kernel/entry/common.c:70 [inline]
 exit_to_user_mode_loop+0x1e4/0x8c0 kernel/entry/common.c:101
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline]
 do_syscall_64+0x23c/0x3c0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00 -> 0x01

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 3303 Comm: syz-executor Tainted: G        W           syzkaller #0 PREEMPT(lazy) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
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EXT4-fs (loop2): unmounting filesystem 00000000-0000-0000-0000-000000000000.