syzbot

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BUG: KCSAN: data-race in d_invalidate / fast_dput

write to 0xffff8881071ce850 of 8 bytes by task 5036 on cpu 1:
 __d_drop fs/dcache.c:575 [inline]
 d_invalidate+0x5b/0x1c0 fs/dcache.c:1651
 proc_invalidate_siblings_dcache+0x1df/0x2a0 fs/proc/inode.c:148
 proc_sys_invalidate_dcache fs/proc/proc_sysctl.c:289 [inline]
 start_unregistering fs/proc/proc_sysctl.c:316 [inline]
 drop_sysctl_table+0xbd/0x270 fs/proc/proc_sysctl.c:1517
 unregister_sysctl_table+0x30/0x50 fs/proc/proc_sysctl.c:1542
 unregister_net_sysctl_table+0x15/0x20 net/sysctl_net.c:177
 __devinet_sysctl_unregister net/ipv4/devinet.c:2701 [inline]
 devinet_sysctl_unregister net/ipv4/devinet.c:2729 [inline]
 inetdev_destroy net/ipv4/devinet.c:334 [inline]
 inetdev_event+0x71c/0xc10 net/ipv4/devinet.c:1656
 notifier_call_chain kernel/notifier.c:85 [inline]
 raw_notifier_call_chain+0x6c/0x1b0 kernel/notifier.c:453
 call_netdevice_notifiers_info+0xae/0x100 net/core/dev.c:2229
 call_netdevice_notifiers_extack net/core/dev.c:2267 [inline]
 call_netdevice_notifiers net/core/dev.c:2281 [inline]
 unregister_netdevice_many_notify+0xda9/0x15d0 net/core/dev.c:12166
 unregister_netdevice_many net/core/dev.c:12229 [inline]
 unregister_netdevice_queue+0x1f5/0x220 net/core/dev.c:12073
 unregister_netdevice include/linux/netdevice.h:3385 [inline]
 unregister_netdev+0xb3/0xe0 net/core/dev.c:12247
 slip_close+0xe4/0x100 drivers/net/slip/slip.c:906
 slip_hangup+0x15/0x20 drivers/net/slip/slip.c:912
 tty_ldisc_hangup+0x132/0x370 drivers/tty/tty_ldisc.c:705
 __tty_hangup+0x3c2/0x540 drivers/tty/tty_io.c:621
 tty_vhangup drivers/tty/tty_io.c:691 [inline]
 tty_ioctl+0x601/0xb80 drivers/tty/tty_io.c:2732
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:598 [inline]
 __se_sys_ioctl+0xcb/0x140 fs/ioctl.c:584
 __x64_sys_ioctl+0x43/0x50 fs/ioctl.c:584
 x64_sys_call+0x1816/0x2ff0 arch/x86/include/generated/asm/syscalls_64.h:17
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff8881071ce850 of 8 bytes by task 3033 on cpu 0:
 hlist_bl_unhashed include/linux/list_bl.h:54 [inline]
 d_unhashed include/linux/dcache.h:361 [inline]
 retain_dentry fs/dcache.c:752 [inline]
 fast_dput+0x5f/0x2c0 fs/dcache.c:848
 dput+0x24/0xd0 fs/dcache.c:905
 path_put fs/namei.c:626 [inline]
 terminate_walk+0x103/0x2a0 fs/namei.c:752
 path_openat+0x1bb0/0x2170 fs/namei.c:4047
 do_filp_open+0x109/0x230 fs/namei.c:4073
 do_sys_openat2+0xa6/0x110 fs/open.c:1435
 do_sys_open fs/open.c:1450 [inline]
 __do_sys_openat fs/open.c:1466 [inline]
 __se_sys_openat fs/open.c:1461 [inline]
 __x64_sys_openat+0xf2/0x120 fs/open.c:1461
 x64_sys_call+0x2e9c/0x2ff0 arch/x86/include/generated/asm/syscalls_64.h:258
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0xffff88823789e388 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 3033 Comm: dhcpcd Not tainted syzkaller #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
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