==================================================================
BUG: KCSAN: data-race in rwsem_down_write_slowpath / rwsem_down_write_slowpath

write to 0xffffc90002787878 of 1 bytes by task 15123 on cpu 0:
 rwsem_try_write_lock kernel/locking/rwsem.c:653 [inline]
 rwsem_down_write_slowpath+0x3eb/0xa80 kernel/locking/rwsem.c:1159
 __down_write_common kernel/locking/rwsem.c:1317 [inline]
 __down_write kernel/locking/rwsem.c:1326 [inline]
 down_write+0xab/0xc0 kernel/locking/rwsem.c:1591
 kernfs_remove_by_name_ns+0x5c/0xf0 fs/kernfs/dir.c:1717
 kernfs_remove_by_name include/linux/kernfs.h:633 [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
 device_remove_groups drivers/base/core.c:2843 [inline]
 device_remove_attrs+0x139/0x1a0 drivers/base/core.c:2976
 device_del+0x361/0x790 drivers/base/core.c:3877
 drop_partition block/partitions/core.c:278 [inline]
 bdev_disk_changed+0x1a3/0xcb0 block/partitions/core.c:674
 loop_reread_partitions drivers/block/loop.c:448 [inline]
 loop_set_status+0x692/0x750 drivers/block/loop.c:1293
 loop_set_status64 drivers/block/loop.c:1393 [inline]
 lo_ioctl+0x672/0x13a0 drivers/block/loop.c:1579
 blkdev_ioctl+0x387/0x460 block/ioctl.c:792
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:597 [inline]
 __se_sys_ioctl+0xce/0x140 fs/ioctl.c:583
 __x64_sys_ioctl+0x43/0x50 fs/ioctl.c:583
 x64_sys_call+0x14b0/0x3000 arch/x86/include/generated/asm/syscalls_64.h:17
 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 0xffffc90002787878 of 1 bytes by task 15139 on cpu 1:
 rwsem_down_write_slowpath+0x45e/0xa80 kernel/locking/rwsem.c:1177
 __down_write_common kernel/locking/rwsem.c:1317 [inline]
 __down_write kernel/locking/rwsem.c:1326 [inline]
 down_write+0xab/0xc0 kernel/locking/rwsem.c:1591
 kernfs_add_one+0x5a/0x280 fs/kernfs/dir.c:796
 kernfs_create_dir_ns+0x90/0xe0 fs/kernfs/dir.c:1098
 sysfs_create_dir_ns+0xd4/0x1d0 fs/sysfs/dir.c:59
 create_dir lib/kobject.c:73 [inline]
 kobject_add_internal+0x47a/0x780 lib/kobject.c:240
 kobject_add_varg lib/kobject.c:374 [inline]
 kobject_init_and_add+0x14a/0x1f0 lib/kobject.c:457
 rx_queue_add_kobject net/core/net-sysfs.c:1260 [inline]
 net_rx_queue_update_kobjects+0x18d/0x540 net/core/net-sysfs.c:1322
 register_queue_kobjects net/core/net-sysfs.c:2114 [inline]
 netdev_register_kobject+0x185/0x230 net/core/net-sysfs.c:2362
 register_netdevice+0x8df/0x1000 net/core/dev.c:11406
 __ip_tunnel_create+0x319/0x430 net/ipv4/ip_tunnel.c:268
 ip_tunnel_init_net+0x210/0x490 net/ipv4/ip_tunnel.c:1147
 ipip_init_net+0x35/0x40 net/ipv4/ipip.c:629
 ops_init+0x22a/0x2e0 net/core/net_namespace.c:137
 setup_net+0x9f/0x230 net/core/net_namespace.c:446
 copy_net_ns+0x308/0x450 net/core/net_namespace.c:581
 create_new_namespaces+0x20e/0x440 kernel/nsproxy.c:130
 unshare_nsproxy_namespaces+0xe6/0x120 kernel/nsproxy.c:226
 ksys_unshare+0x3cd/0x6d0 kernel/fork.c:3171
 __do_sys_unshare kernel/fork.c:3242 [inline]
 __se_sys_unshare kernel/fork.c:3240 [inline]
 __x64_sys_unshare+0x1f/0x30 kernel/fork.c:3240
 x64_sys_call+0x2ae6/0x3000 arch/x86/include/generated/asm/syscalls_64.h:273
 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: 0x00 -> 0x01

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 15139 Comm: syz.4.3523 Tainted: G        W           syzkaller #0 PREEMPT(voluntary) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
==================================================================