syzbot

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BUG: KCSAN: data-race in d_walk / shrink_dentry_list

write to 0xffff88811e13ee40 of 4 bytes by task 11695 on cpu 1:
 d_shrink_add fs/dcache.c:456 [inline]
 __dput_to_list fs/dcache.c:928 [inline]
 shrink_dentry_list+0x460/0x540 fs/dcache.c:1200
 shrink_dcache_parent+0x4d/0x3f0
 d_invalidate+0x6e/0x1a0 fs/dcache.c:1737
 proc_invalidate_siblings_dcache+0x1e3/0x2d0 fs/proc/inode.c:150
 proc_flush_pid+0x16/0x20 fs/proc/base.c:3346
 release_task+0xabf/0xbb0 kernel/exit.c:223
 exit_notify kernel/exit.c:705 [inline]
 do_exit+0x1081/0x16a0 kernel/exit.c:826
 do_group_exit+0xa5/0x160 kernel/exit.c:935
 get_signal+0x8cf/0x15d0 kernel/signal.c:2862
 arch_do_signal_or_restart+0x8c/0x2e0 arch/x86/kernel/signal.c:868
 handle_signal_work kernel/entry/common.c:148 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:172 [inline]
 exit_to_user_mode_prepare+0x113/0x190 kernel/entry/common.c:207
 __syscall_exit_to_user_mode_work kernel/entry/common.c:289 [inline]
 syscall_exit_to_user_mode+0x20/0x40 kernel/entry/common.c:300
 do_syscall_64+0x50/0xd0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff88811e13ee40 of 4 bytes by task 1820 on cpu 0:
 d_walk+0x25c/0x4b0 fs/dcache.c:1381
 shrink_dcache_parent+0x85/0x3f0 fs/dcache.c:1625
 d_invalidate+0x6e/0x1a0 fs/dcache.c:1737
 proc_invalidate_siblings_dcache+0x1e3/0x2d0 fs/proc/inode.c:150
 proc_flush_pid+0x16/0x20 fs/proc/base.c:3346
 release_task+0xabf/0xbb0 kernel/exit.c:223
 wait_task_zombie kernel/exit.c:1121 [inline]
 wait_consider_task+0x1078/0x1930 kernel/exit.c:1348
 do_wait_thread kernel/exit.c:1411 [inline]
 do_wait+0x182/0x680 kernel/exit.c:1528
 kernel_wait4+0x14b/0x1b0 kernel/exit.c:1691
 __do_sys_wait4 kernel/exit.c:1719 [inline]
 __se_sys_wait4 kernel/exit.c:1715 [inline]
 __x64_sys_wait4+0x90/0x120 kernel/exit.c:1715
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x0020000c -> 0x0028040c

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 1820 Comm: syz-executor.2 Not tainted 5.17.0-rc3-syzkaller-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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