syzbot

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BUG: KCSAN: data-race in __dentry_kill / shrink_dentry_list

read-write to 0xffff888106242840 of 4 bytes by task 19825 on cpu 0:
 d_shrink_del fs/dcache.c:461 [inline]
 shrink_dentry_list+0x19f/0x3e0 fs/dcache.c:1086
 shrink_dcache_parent+0x43/0x1b0
 d_invalidate+0xa9/0x1c0 fs/dcache.c:1604
 proc_invalidate_siblings_dcache+0x1db/0x2b0 fs/proc/inode.c:142
 proc_flush_pid+0x1d/0x30 fs/proc/base.c:3477
 release_task+0xad9/0xc20 kernel/exit.c:280
 wait_task_zombie kernel/exit.c:1250 [inline]
 wait_consider_task+0x116e/0x1680 kernel/exit.c:1477
 do_wait_thread kernel/exit.c:1540 [inline]
 __do_wait+0x100/0x500 kernel/exit.c:1658
 do_wait+0xaf/0x270 kernel/exit.c:1692
 kernel_wait4+0x164/0x1d0 kernel/exit.c:1851
 __do_sys_wait4 kernel/exit.c:1879 [inline]
 __se_sys_wait4 kernel/exit.c:1875 [inline]
 __x64_sys_wait4+0x94/0x120 kernel/exit.c:1875
 x64_sys_call+0x2529/0x2d60 arch/x86/include/generated/asm/syscalls_64.h:62
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888106242840 of 4 bytes by task 27225 on cpu 1:
 dentry_unlist fs/dcache.c:585 [inline]
 __dentry_kill+0x2af/0x4c0 fs/dcache.c:629
 dput+0x5c/0xd0 fs/dcache.c:857
 proc_invalidate_siblings_dcache+0x1e3/0x2b0 fs/proc/inode.c:143
 proc_flush_pid+0x1d/0x30 fs/proc/base.c:3477
 release_task+0xb7f/0xc20 kernel/exit.c:280
 exit_notify kernel/exit.c:776 [inline]
 do_exit+0xf62/0x17f0 kernel/exit.c:959
 do_group_exit+0x102/0x150 kernel/exit.c:1088
 get_signal+0xf2a/0x1070 kernel/signal.c:2918
 arch_do_signal_or_restart+0x95/0x4b0 arch/x86/kernel/signal.c:337
 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+0xd6/0x1c0 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x0048040c -> 0x0000000c

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 27225 Comm: syz.3.7623 Not tainted 6.12.0-rc7-syzkaller-00212-g4a5df3796467 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/30/2024
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