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BUG: KMSAN: uninit-value in rcu_segcblist_enqueue+0x239/0x2d0 kernel/rcu/rcu_segcblist.c:150
CPU: 1 PID: 3595 Comm: syz-executor5 Not tainted 4.16.0+ #83
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x185/0x1d0 lib/dump_stack.c:53
 kmsan_report+0x142/0x240 mm/kmsan/kmsan.c:1067
 __msan_warning_32+0x6c/0xb0 mm/kmsan/kmsan_instr.c:676
 rcu_segcblist_enqueue+0x239/0x2d0 kernel/rcu/rcu_segcblist.c:150
 __call_rcu+0x227/0xef0 kernel/rcu/tree.c:3060
 call_rcu_sched+0x32/0x40 kernel/rcu/tree.c:3100
 __dentry_kill+0xc63/0xd20 fs/dcache.c:344
 dentry_kill fs/dcache.c:616 [inline]
 dput+0x72e/0xce0 fs/dcache.c:831
 do_unlinkat+0x46f/0x12e0 fs/namei.c:4043
 SYSC_unlink+0x8a/0xa0 fs/namei.c:4088
 SyS_unlink+0x36/0x50 fs/namei.c:4086
 do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x3d/0xa2
RIP: 0033:0x455067
RSP: 002b:0000000000a3d9e8 EFLAGS: 00000206 ORIG_RAX: 0000000000000057
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000455067
RDX: 000000000255a9b3 RSI: 0000000000a3da80 RDI: 0000000000a3da80
RBP: 0000000000a3f790 R08: 0000000000000000 R09: 000000000000000f
R10: 000000000000000a R11: 0000000000000206 R12: 000000000255a940
R13: 0000000000000000 R14: 00000000000000b3 R15: 000000000000a23e

Uninit was stored to memory at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:278 [inline]
 kmsan_save_stack mm/kmsan/kmsan.c:293 [inline]
 kmsan_internal_chain_origin+0x12b/0x210 mm/kmsan/kmsan.c:684
 __msan_chain_origin+0x69/0xc0 mm/kmsan/kmsan_instr.c:521
 rcu_segcblist_enqueue+0x275/0x2d0 kernel/rcu/rcu_segcblist.c:151
 __call_rcu+0x227/0xef0 kernel/rcu/tree.c:3060
 call_rcu_sched+0x32/0x40 kernel/rcu/tree.c:3100
 release_task+0x24b9/0x2530 kernel/exit.c:223
 exit_notify kernel/exit.c:736 [inline]
 do_exit+0x2d91/0x38d0 kernel/exit.c:887
 do_group_exit+0x1a0/0x360 kernel/exit.c:970
 get_signal+0x1320/0x1f20 kernel/signal.c:2469
 do_signal+0xb8/0x1c80 arch/x86/kernel/signal.c:809
 exit_to_usermode_loop arch/x86/entry/common.c:162 [inline]
 prepare_exit_to_usermode+0x271/0x3a0 arch/x86/entry/common.c:196
 syscall_return_slowpath+0xe9/0x700 arch/x86/entry/common.c:265
 do_syscall_64+0x36d/0x430 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x3d/0xa2
Local variable description: ----flags.i.i.i.i@_raw_spin_lock_irqsave
Variable was created at:
 _raw_spin_lock_irqsave+0x45/0xf0 kernel/locking/spinlock.c:150
 add_device_randomness+0x34b/0x400 drivers/char/random.c:991
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