syzbot

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BUG: KCSAN: data-race in __dentry_kill / shrink_dentry_list

read-write to 0xffff88810058ee40 of 4 bytes by task 25183 on cpu 1:
 d_shrink_del fs/dcache.c:449 [inline]
 shrink_dentry_list+0x19f/0x3e0 fs/dcache.c:1074
 shrink_dcache_parent+0x43/0x1b0
 d_invalidate+0xa6/0x1c0 fs/dcache.c:1592
 proc_invalidate_siblings_dcache+0x1db/0x2b0 fs/proc/inode.c:142
 proc_flush_pid+0x1d/0x30 fs/proc/base.c:3419
 release_task+0xae6/0xc30 kernel/exit.c:282
 wait_task_zombie kernel/exit.c:1189 [inline]
 wait_consider_task+0x116b/0x1670 kernel/exit.c:1416
 do_wait_thread kernel/exit.c:1479 [inline]
 __do_wait+0x100/0x500 kernel/exit.c:1597
 do_wait+0xaf/0x270 kernel/exit.c:1631
 kernel_wait4+0x164/0x1d0 kernel/exit.c:1790
 __do_sys_wait4 kernel/exit.c:1818 [inline]
 __se_sys_wait4 kernel/exit.c:1814 [inline]
 __x64_sys_wait4+0x94/0x120 kernel/exit.c:1814
 x64_sys_call+0x61d/0x2d30 arch/x86/include/generated/asm/syscalls_64.h:62
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x1d0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff88810058ee40 of 4 bytes by task 27057 on cpu 0:
 dentry_unlist fs/dcache.c:573 [inline]
 __dentry_kill+0x2a9/0x4b0 fs/dcache.c:617
 dput+0x5c/0xd0 fs/dcache.c:845
 proc_invalidate_siblings_dcache+0x1e3/0x2b0 fs/proc/inode.c:143
 proc_flush_pid+0x1d/0x30 fs/proc/base.c:3419
 release_task+0xb91/0xc30 kernel/exit.c:282
 exit_notify kernel/exit.c:774 [inline]
 do_exit+0xf7d/0x1740 kernel/exit.c:898
 do_group_exit+0x102/0x150 kernel/exit.c:1027
 get_signal+0xf2f/0x1080 kernel/signal.c:2911
 arch_do_signal_or_restart+0x95/0x4b0 arch/x86/kernel/signal.c:310
 exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0x59/0x130 kernel/entry/common.c:218
 do_syscall_64+0xda/0x1d0 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x0048040c -> 0x0000000c

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 27057 Comm: syz-executor.0 Tainted: G        W          6.9.0-syzkaller-08284-gea5f6ad9ad96 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024
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