syzbot

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BUG: KCSAN: data-race in __dentry_kill / shrink_dentry_list

read-write to 0xffff888106ee09c0 of 4 bytes by task 21974 on cpu 0:
 d_shrink_del fs/dcache.c:515 [inline]
 shrink_dentry_list+0x1a6/0x3d0 fs/dcache.c:1140
 shrink_dcache_parent+0x42/0x1b0 fs/dcache.c:-1
 d_invalidate+0xa6/0x1c0 fs/dcache.c:1658
 proc_invalidate_siblings_dcache+0x1c0/0x2a0 fs/proc/inode.c:142
 proc_flush_pid+0x1d/0x30 fs/proc/base.c:3483
 release_task+0x992/0xb60 kernel/exit.c:293
 wait_task_zombie kernel/exit.c:1264 [inline]
 wait_consider_task+0x114a/0x1660 kernel/exit.c:1491
 do_wait_thread kernel/exit.c:1554 [inline]
 __do_wait+0xfa/0x510 kernel/exit.c:1672
 do_wait+0xb7/0x260 kernel/exit.c:1706
 kernel_wait4+0x16b/0x1e0 kernel/exit.c:1865
 __do_sys_wait4 kernel/exit.c:1893 [inline]
 __se_sys_wait4 kernel/exit.c:1889 [inline]
 __x64_sys_wait4+0x91/0x120 kernel/exit.c:1889
 x64_sys_call+0x2a66/0x2ff0 arch/x86/include/generated/asm/syscalls_64.h:62
 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 0xffff888106ee09c0 of 4 bytes by task 22879 on cpu 1:
 dentry_unlist fs/dcache.c:639 [inline]
 __dentry_kill+0x2aa/0x4b0 fs/dcache.c:683
 dput+0x5e/0xd0 fs/dcache.c:911
 proc_invalidate_siblings_dcache+0x1c8/0x2a0 fs/proc/inode.c:143
 proc_flush_pid+0x1d/0x30 fs/proc/base.c:3483
 release_task+0x992/0xb60 kernel/exit.c:293
 exit_notify kernel/exit.c:778 [inline]
 do_exit+0xd81/0x15c0 kernel/exit.c:973
 do_group_exit+0xff/0x140 kernel/exit.c:1102
 get_signal+0xe59/0xf70 kernel/signal.c:3034
 arch_do_signal_or_restart+0x96/0x480 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop+0x7a/0x100 kernel/entry/common.c:40
 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]
 do_syscall_64+0x1d6/0x200 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x0024040c -> 0x0000000c

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 22879 Comm: syz.7.6529 Not tainted 6.17.0-rc1-syzkaller-00014-g0e39a731820a #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
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