EXT4-fs (loop0): unmounting filesystem 00000000-0000-0000-0000-000000000000.
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BUG: KCSAN: data-race in rwsem_down_write_slowpath / rwsem_down_write_slowpath

write to 0xffffc900001fbc10 of 1 bytes by task 32454 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+0xad/0xc0 kernel/locking/rwsem.c:1632
 kernfs_activate+0x50/0x220 fs/kernfs/dir.c:1462
 kernfs_add_one+0x2cf/0x350 fs/kernfs/dir.c:868
 __kernfs_create_file+0x145/0x180 fs/kernfs/file.c:1079
 sysfs_add_file_mode_ns+0x132/0x1b0 fs/sysfs/file.c:316
 sysfs_merge_group+0xed/0x1c0 fs/sysfs/group.c:382
 dpm_sysfs_add+0xaf/0x1e0 drivers/base/power/sysfs.c:704
 device_add+0x3bc/0x790 drivers/base/core.c:3721
 netdev_register_kobject+0x127/0x240 net/core/net-sysfs.c:2340
 register_netdevice+0xaf7/0x11a0 net/core/dev.c:11503
 __ip_tunnel_create+0x31d/0x420 net/ipv4/ip_tunnel.c:268
 ip_tunnel_init_net+0x208/0x490 net/ipv4/ip_tunnel.c:1137
 ipip_init_net+0x35/0x40 net/ipv4/ipip.c:642
 ops_init+0x22a/0x2e0 net/core/net_namespace.c:137
 setup_net+0x9f/0x230 net/core/net_namespace.c:443
 copy_net_ns+0x333/0x490 net/core/net_namespace.c:582
 create_new_namespaces+0x1f6/0x420 kernel/nsproxy.c:132
 unshare_nsproxy_namespaces+0x115/0x150 kernel/nsproxy.c:234
 ksys_unshare+0x42b/0x710 kernel/fork.c:3292
 __do_sys_unshare kernel/fork.c:3356 [inline]
 __se_sys_unshare kernel/fork.c:3354 [inline]
 __x64_sys_unshare+0x1f/0x30 kernel/fork.c:3354
 x64_sys_call+0x1e33/0x2550 arch/x86/include/generated/asm/syscalls_64.h:273
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x112/0x360 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffffc900001fbc10 of 1 bytes by task 22473 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+0xad/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
 loop_sysfs_exit drivers/block/loop.c:746 [inline]
 __loop_clr_fd drivers/block/loop.c:1167 [inline]
 lo_release+0x26b/0x3f0 drivers/block/loop.c:1773
 bdev_release+0x375/0x3d0 block/bdev.c:-1
 blkdev_release+0x15/0x20 block/fops.c:682
 __fput+0x29e/0x630 fs/file_table.c:512
 fput_close_sync+0xad/0x190 fs/file_table.c:617
 __do_sys_close fs/open.c:1560 [inline]
 __se_sys_close fs/open.c:1545 [inline]
 __x64_sys_close+0x55/0xf0 fs/open.c:1545
 x64_sys_call+0x812/0x2550 arch/x86/include/generated/asm/syscalls_64.h:4
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x112/0x360 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00 -> 0x01

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 22473 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(lazy) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
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