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BUG: KCSAN: data-race in kernfs_iop_permission / kernfs_link_sibling

read-write to 0xffff8881018fa140 of 8 bytes by task 2078 on cpu 0:
 kernfs_link_sibling+0x1e7/0x230 fs/kernfs/dir.c:387
 kernfs_add_one+0x260/0x390 fs/kernfs/dir.c:770
 kernfs_create_dir_ns+0x100/0x150 fs/kernfs/dir.c:1046
 sysfs_create_dir_ns+0xd7/0x1d0 fs/sysfs/dir.c:59
 create_dir lib/kobject.c:65 [inline]
 kobject_add_internal+0x47b/0x780 lib/kobject.c:233
 kobject_add_varg lib/kobject.c:367 [inline]
 kobject_init_and_add+0x15e/0x200 lib/kobject.c:450
 nfs_netns_client_alloc fs/nfs/sysfs.c:180 [inline]
 nfs_netns_sysfs_setup+0xbc/0x150 fs/nfs/sysfs.c:199
 nfs_clients_init+0xf9/0x100 fs/nfs/client.c:1177
 nfs_net_init+0x15/0x20 fs/nfs/inode.c:2429
 ops_init+0x1fc/0x2c0 net/core/net_namespace.c:136
 setup_net+0x2cd/0x710 net/core/net_namespace.c:339
 copy_net_ns+0x384/0x520 net/core/net_namespace.c:491
 create_new_namespaces+0x228/0x430 kernel/nsproxy.c:110
 copy_namespaces+0x14d/0x1b0 kernel/nsproxy.c:179
 copy_process+0x102f/0x2180 kernel/fork.c:2507
 kernel_clone+0x169/0x560 kernel/fork.c:2912
 __do_sys_clone kernel/fork.c:3055 [inline]
 __se_sys_clone kernel/fork.c:3039 [inline]
 __x64_sys_clone+0xe8/0x120 kernel/fork.c:3039
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

read to 0xffff8881018fa140 of 8 bytes by task 9789 on cpu 1:
 kernfs_refresh_inode fs/kernfs/inode.c:181 [inline]
 kernfs_iop_permission+0x165/0x1b0 fs/kernfs/inode.c:289
 do_inode_permission fs/namei.c:461 [inline]
 inode_permission+0x184/0x300 fs/namei.c:528
 may_lookup fs/namei.c:1720 [inline]
 link_path_walk+0x19e/0x7e0 fs/namei.c:2267
 path_openat+0x1a1/0x1d10 fs/namei.c:3789
 do_filp_open+0xf6/0x200 fs/namei.c:3820
 do_sys_openat2+0xab/0x110 fs/open.c:1407
 do_sys_open fs/open.c:1422 [inline]
 __do_sys_openat fs/open.c:1438 [inline]
 __se_sys_openat fs/open.c:1433 [inline]
 __x64_sys_openat+0xf3/0x120 fs/open.c:1433
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

value changed: 0x000000000000000b -> 0x000000000000000c

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 9789 Comm: udevd Not tainted 6.5.0-rc6-syzkaller-00038-g16931859a650 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023
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