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BUG: KCSAN: data-race in rwsem_down_write_slowpath / rwsem_down_write_slowpath

write to 0xffffc90003ce7a98 of 1 bytes by task 23216 on cpu 0:
 rwsem_try_write_lock kernel/locking/rwsem.c:653 [inline]
 rwsem_down_write_slowpath+0x3c9/0xa90 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_activate+0x50/0x220 fs/kernfs/dir.c:1430
 kernfs_add_one+0x212/0x280 fs/kernfs/dir.c:839
 __kernfs_create_file+0x145/0x180 fs/kernfs/file.c:1086
 sysfs_add_file_mode_ns+0x132/0x1b0 fs/sysfs/file.c:313
 create_files fs/sysfs/group.c:82 [inline]
 internal_create_group+0x441/0x9e0 fs/sysfs/group.c:189
 internal_create_groups fs/sysfs/group.c:229 [inline]
 sysfs_create_groups+0x3f/0xf0 fs/sysfs/group.c:255
 setup_gid_attrs drivers/infiniband/core/sysfs.c:1118 [inline]
 ib_setup_port_attrs+0xe89/0x1400 drivers/infiniband/core/sysfs.c:1394
 add_one_compat_dev+0x297/0x390 drivers/infiniband/core/device.c:977
 rdma_dev_init_net+0x1b9/0x240 drivers/infiniband/core/device.c:1193
 ops_init+0x22a/0x2e0 net/core/net_namespace.c:137
 setup_net+0x9f/0x230 net/core/net_namespace.c:446
 copy_net_ns+0x310/0x450 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+0x3f2/0x6f0 kernel/fork.c:3173
 __do_sys_unshare kernel/fork.c:3244 [inline]
 __se_sys_unshare kernel/fork.c:3242 [inline]
 __x64_sys_unshare+0x1f/0x30 kernel/fork.c:3242
 x64_sys_call+0x1cef/0x3020 arch/x86/include/generated/asm/syscalls_64.h:273
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x12c/0x370 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffffc90003ce7a98 of 1 bytes by task 23219 on cpu 1:
 rwsem_down_write_slowpath+0x43d/0xa90 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
 kset_register lib/kobject.c:870 [inline]
 kset_create_and_add+0x144/0x1b0 lib/kobject.c:1011
 register_queue_kobjects net/core/net-sysfs.c:2106 [inline]
 netdev_register_kobject+0x133/0x230 net/core/net-sysfs.c:2362
 register_netdevice+0x8f3/0x1000 net/core/dev.c:11424
 ldisc_open+0x376/0x5c0 drivers/net/caif/caif_serial.c:342
 tty_ldisc_open+0x5d/0xb0 drivers/tty/tty_ldisc.c:432
 tty_set_ldisc+0x1db/0x380 drivers/tty/tty_ldisc.c:563
 tiocsetd+0x51/0x60 drivers/tty/tty_io.c:2429
 tty_ioctl+0xa78/0xb80 drivers/tty/tty_io.c:2728
 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+0x1563/0x3020 arch/x86/include/generated/asm/syscalls_64.h:17
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x12c/0x370 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: 23219 Comm: syz.6.2588 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
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