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BUG: KCSAN: data-race in dput / select_collect

write to 0xffff88812da98900 of 4 bytes by task 8468 on cpu 0:
 d_lru_del fs/dcache.c:410 [inline]
 select_collect+0xaf/0x2a0 fs/dcache.c:1505
 d_walk+0x298/0x4c0 fs/dcache.c:1326
 shrink_dcache_parent+0x85/0x3c0 fs/dcache.c:1565
 d_invalidate+0x70/0x1b0 fs/dcache.c:1677
 proc_invalidate_siblings_dcache+0x1e3/0x2d0 fs/proc/inode.c:150
 proc_flush_pid+0x16/0x20 fs/proc/base.c:3323
 release_task+0xb01/0xd30 kernel/exit.c:221
 wait_task_zombie kernel/exit.c:1091 [inline]
 wait_consider_task+0xf89/0x1820 kernel/exit.c:1318
 do_wait_thread kernel/exit.c:1381 [inline]
 do_wait+0x1b1/0x4a0 kernel/exit.c:1452
 kernel_wait4+0x13c/0x1a0 kernel/exit.c:1614
 __do_sys_wait4 kernel/exit.c:1642 [inline]
 __se_sys_wait4 kernel/exit.c:1638 [inline]
 __x64_sys_wait4+0x7a/0x100 kernel/exit.c:1638
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff88812da98900 of 4 bytes by task 11760 on cpu 1:
 fast_dput fs/dcache.c:746 [inline]
 dput+0x2f/0x420 fs/dcache.c:865
 proc_invalidate_siblings_dcache+0x1eb/0x2d0 fs/proc/inode.c:151
 proc_flush_pid+0x16/0x20 fs/proc/base.c:3323
 release_task+0xc1e/0xd30 kernel/exit.c:221
 exit_notify kernel/exit.c:684 [inline]
 do_exit+0xeb1/0x1630 kernel/exit.c:829
 do_group_exit+0xc8/0x170 kernel/exit.c:906
 get_signal+0xf9b/0x1510 kernel/signal.c:2758
 arch_do_signal+0x25/0x260 arch/x86/kernel/signal.c:811
 exit_to_user_mode_loop kernel/entry/common.c:161 [inline]
 exit_to_user_mode_prepare+0xde/0x170 kernel/entry/common.c:191
 syscall_exit_to_user_mode+0x16/0x30 kernel/entry/common.c:266
 do_syscall_64+0x45/0x80 arch/x86/entry/common.c:56
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 11760 Comm: syz-executor.2 Not tainted 5.10.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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