syzbot

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BUG: KCSAN: data-race in __dentry_kill / proc_sys_compare

write to 0xffff888107dfed80 of 4 bytes by task 12 on cpu 1:
 d_lru_del fs/dcache.c:513 [inline]
 __dentry_kill+0xab/0x4d0 fs/dcache.c:713
 finish_dput+0x2b/0x200 fs/dcache.c:927
 dput+0x52/0x60 fs/dcache.c:976
 proc_invalidate_siblings_dcache+0x1d0/0x2b0 fs/proc/inode.c:143
 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
 drop_sysctl_table+0x1cb/0x270 fs/proc/proc_sysctl.c:1524
 drop_sysctl_table+0x1cb/0x270 fs/proc/proc_sysctl.c:1524
 drop_sysctl_table+0x1cb/0x270 fs/proc/proc_sysctl.c:1524
 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:2735 [inline]
 devinet_exit_net+0x10a/0x190 net/ipv4/devinet.c:2897
 ops_exit_list net/core/net_namespace.c:199 [inline]
 ops_undo_list+0x285/0x420 net/core/net_namespace.c:252
 cleanup_net+0x37c/0x5b0 net/core/net_namespace.c:702
 process_one_work kernel/workqueue.c:3314 [inline]
 process_scheduled_works+0x4f0/0x9c0 kernel/workqueue.c:3397
 worker_thread+0x58a/0x780 kernel/workqueue.c:3478
 kthread+0x22a/0x280 kernel/kthread.c:436
 ret_from_fork+0x146/0x330 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

read to 0xffff888107dfed80 of 4 bytes by task 3544 on cpu 0:
 d_in_lookup include/linux/dcache.h:403 [inline]
 proc_sys_compare+0x85/0x170 fs/proc/proc_sysctl.c:926
 __d_lookup_rcu_op_compare+0x207/0x270 fs/dcache.c:2332
 __d_lookup_rcu+0x2bf/0x2d0 fs/dcache.c:2384
 d_alloc_parallel+0x247/0xce0 fs/dcache.c:2690
 __lookup_slow+0x96/0x260 fs/namei.c:1900
 lookup_slow+0x3c/0x60 fs/namei.c:1932
 walk_component fs/namei.c:2278 [inline]
 link_path_walk+0x946/0xe30 fs/namei.c:2652
 path_openat+0x1c6/0x2050 fs/namei.c:4854
 do_file_open+0x16c/0x290 fs/namei.c:4887
 do_sys_openat2+0x94/0x130 fs/open.c:1364
 do_sys_open fs/open.c:1370 [inline]
 __do_sys_openat fs/open.c:1386 [inline]
 __se_sys_openat fs/open.c:1381 [inline]
 __x64_sys_openat+0xf2/0x120 fs/open.c:1381
 x64_sys_call+0x1e39/0x3020 arch/x86/include/generated/asm/syscalls_64.h:258
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x12c/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x0014000e -> 0x0000400e

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 3544 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
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