syzbot

9pnet_fd: Insufficient options for proto=fd
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BUG: KCSAN: data-race in __dentry_kill / shrink_dentry_list

read-write to 0xffff8881047c3240 of 4 bytes by task 11786 on cpu 0:
 d_shrink_del fs/dcache.c:489 [inline]
 shrink_dentry_list+0x19f/0x3e0 fs/dcache.c:1114
 shrink_dcache_parent+0x43/0x1b0
 d_invalidate+0xa9/0x1c0 fs/dcache.c:1632
 proc_invalidate_siblings_dcache+0x1db/0x2b0 fs/proc/inode.c:142
 proc_flush_pid+0x1d/0x30 fs/proc/base.c:3491
 release_task+0xad9/0xc20 kernel/exit.c:279
 wait_task_zombie kernel/exit.c:1249 [inline]
 wait_consider_task+0x116e/0x1680 kernel/exit.c:1476
 do_wait_thread kernel/exit.c:1539 [inline]
 __do_wait+0x100/0x500 kernel/exit.c:1657
 do_wait+0xaf/0x270 kernel/exit.c:1691
 kernel_wait4+0x164/0x1d0 kernel/exit.c:1850
 __do_sys_wait4 kernel/exit.c:1878 [inline]
 __se_sys_wait4 kernel/exit.c:1874 [inline]
 __x64_sys_wait4+0x94/0x120 kernel/exit.c:1874
 x64_sys_call+0x25a2/0x2dc0 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 0xffff8881047c3240 of 4 bytes by task 12597 on cpu 1:
 dentry_unlist fs/dcache.c:613 [inline]
 __dentry_kill+0x2af/0x4c0 fs/dcache.c:657
 dput+0x5c/0xd0 fs/dcache.c:885
 proc_invalidate_siblings_dcache+0x1e3/0x2b0 fs/proc/inode.c:143
 proc_flush_pid+0x1d/0x30 fs/proc/base.c:3491
 release_task+0xb7f/0xc20 kernel/exit.c:279
 exit_notify kernel/exit.c:775 [inline]
 do_exit+0xf5d/0x17f0 kernel/exit.c:958
 do_group_exit+0x102/0x150 kernel/exit.c:1087
 get_signal+0xeb9/0x1000 kernel/signal.c:3036
 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:329 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0x62/0x120 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: 12597 Comm: syz.1.3143 Not tainted 6.14.0-rc3-syzkaller-00060-g6537cfb395f3 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
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