==================================================================
BUG: KMSAN: uninit-value in rcu_cblist_dequeue+0x233/0x270 kernel/rcu/rcu_segcblist.c:55
CPU: 0 PID: 20057 Comm: modprobe Not tainted 4.17.0+ #8
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x185/0x1d0 lib/dump_stack.c:113
 kmsan_report+0x188/0x2a0 mm/kmsan/kmsan.c:1122
 __msan_warning_32+0x70/0xc0 mm/kmsan/kmsan_instr.c:620
 rcu_cblist_dequeue+0x233/0x270 kernel/rcu/rcu_segcblist.c:55
 rcu_do_batch kernel/rcu/tree.c:2673 [inline]
 invoke_rcu_callbacks kernel/rcu/tree.c:2930 [inline]
 __rcu_process_callbacks kernel/rcu/tree.c:2897 [inline]
 rcu_process_callbacks+0x19a7/0x2060 kernel/rcu/tree.c:2914
 __do_softirq+0x592/0x979 kernel/softirq.c:285
 invoke_softirq kernel/softirq.c:365 [inline]
 irq_exit+0x202/0x240 kernel/softirq.c:405
 exiting_irq+0xe/0x10 arch/x86/include/asm/apic.h:525
 smp_apic_timer_interrupt+0x64/0x90 arch/x86/kernel/apic/apic.c:1055
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:863
 </IRQ>
RIP: 0033:0x7f163e93e892
RSP: 002b:00007fffaf556838 EFLAGS: 00000206 ORIG_RAX: ffffffffffffff13
RAX: 000000000000005f RBX: 00007f163e38fea8 RCX: 0000000000000000
RDX: 0000000000000467 RSI: 00007f163e7139c8 RDI: 00007f163e398a5f
RBP: 00007f163eb46ee8 R08: 0000000001ead4e2 R09: 0000000000000010
R10: 00007fffaf5568d0 R11: 00007fffaf5568d0 R12: 0000000000000004
R13: 000000007ab53890 R14: 0000000000000002 R15: 00007fffaf556a58

Uninit was stored to memory at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:279 [inline]
 kmsan_save_stack mm/kmsan/kmsan.c:294 [inline]
 kmsan_internal_chain_origin+0x12b/0x210 mm/kmsan/kmsan.c:686
 __msan_chain_origin+0x69/0xc0 mm/kmsan/kmsan_instr.c:464
 rcu_segcblist_enqueue+0x24c/0x2d0 kernel/rcu/rcu_segcblist.c:150
 __call_rcu+0x227/0xef0 kernel/rcu/tree.c:3057
 call_rcu_sched+0x32/0x40 kernel/rcu/tree.c:3097
 shmem_destroy_inode+0xbc/0xe0 mm/shmem.c:3884
 destroy_inode fs/inode.c:267 [inline]
 evict+0xc82/0xdb0 fs/inode.c:575
 iput_final fs/inode.c:1520 [inline]
 iput+0xb02/0xe50 fs/inode.c:1546
 dentry_unlink_inode+0x850/0x8b0 fs/dcache.c:376
 __dentry_kill+0x87e/0xd40 fs/dcache.c:568
 dentry_kill+0x1a9/0xc70 fs/dcache.c:674
 dput+0x277/0x560 fs/dcache.c:850
 __fput+0x95d/0xa30 fs/file_table.c:227
 ____fput+0x37/0x40 fs/file_table.c:243
 task_work_run+0x22e/0x2b0 kernel/task_work.c:113
 exit_task_work include/linux/task_work.h:22 [inline]
 do_exit+0x110e/0x3930 kernel/exit.c:867
 do_group_exit+0x1a0/0x360 kernel/exit.c:970
 __do_sys_exit_group+0x21/0x30 kernel/exit.c:981
 __se_sys_exit_group+0x14/0x20 kernel/exit.c:979
 __x64_sys_exit_group+0x4c/0x50 kernel/exit.c:979
 do_syscall_64+0x15b/0x230 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Uninit was created at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:279 [inline]
 kmsan_internal_poison_shadow+0xb8/0x1b0 mm/kmsan/kmsan.c:189
 kmsan_kmalloc+0x94/0x100 mm/kmsan/kmsan.c:315
 kmem_cache_alloc+0xa97/0xb70 mm/slub.c:2772
 __d_alloc+0x8b/0xe40 fs/dcache.c:1638
 d_alloc_pseudo+0x68/0x80 fs/dcache.c:1766
 __shmem_file_setup+0x395/0x860 mm/shmem.c:4235
 shmem_file_setup mm/shmem.c:4290 [inline]
 __do_sys_memfd_create mm/shmem.c:3750 [inline]
 __se_sys_memfd_create+0x60d/0xa20 mm/shmem.c:3693
 __x64_sys_memfd_create+0x92/0xc0 mm/shmem.c:3693
 do_syscall_64+0x15b/0x230 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
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