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BUG: KMSAN: uninit-value in rcu_segcblist_enqueue+0x239/0x2d0 kernel/rcu/rcu_segcblist.c:150
CPU: 1 PID: 4508 Comm: syz-executor989 Not tainted 4.16.0+ #87
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:683
 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
 radix_tree_node_free lib/radix-tree.c:455 [inline]
 delete_node+0x3cd/0xc70 lib/radix-tree.c:785
 __radix_tree_delete+0x1260/0x1330 lib/radix-tree.c:2001
 radix_tree_delete_item+0x5bb/0x810 lib/radix-tree.c:2050
 idr_remove+0xa4/0xc0 lib/idr.c:157
 free_pid+0x2e0/0x450 kernel/pid.c:152
 __change_pid kernel/pid.c:294 [inline]
 detach_pid+0x35a/0x370 kernel/pid.c:299
 __unhash_process kernel/exit.c:77 [inline]
 __exit_signal kernel/exit.c:156 [inline]
 release_task+0x10e0/0x2530 kernel/exit.c:200
 wait_task_zombie kernel/exit.c:1163 [inline]
 wait_consider_task+0x2e29/0x4520 kernel/exit.c:1390
 do_wait_thread kernel/exit.c:1453 [inline]
 do_wait+0x5f8/0xbc0 kernel/exit.c:1524
 kernel_wait4+0x337/0x4b0 kernel/exit.c:1667
 SYSC_wait4+0x111/0x280 kernel/exit.c:1679
 SyS_wait4+0x64/0x90 kernel/exit.c:1675
 do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x3d/0xa2
RIP: 0033:0x405f1a
RSP: 002b:00007ffe1a37b688 EFLAGS: 00000246 ORIG_RAX: 000000000000003d
RAX: ffffffffffffffda RBX: 0000000000006129 RCX: 0000000000405f1a
RDX: 0000000040000001 RSI: 00007ffe1a37b690 RDI: ffffffffffffffff
RBP: 0000000000006129 R08: 000000000000119c R09: 00000000011b2880
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000000e80c7
R13: 00000000006db428 R14: 0000000000000000 R15: 0000000000000000

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:528
 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
Uninit was created at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:278 [inline]
 kmsan_internal_poison_shadow+0xb8/0x1b0 mm/kmsan/kmsan.c:188
 kmsan_kmalloc+0x94/0x100 mm/kmsan/kmsan.c:314
 kmem_cache_alloc+0xaab/0xb90 mm/slub.c:2756
 alloc_pid+0x7f/0xce0 kernel/pid.c:168
 copy_process+0x3fb7/0x9bb0 kernel/fork.c:1808
 _do_fork+0x311/0xf00 kernel/fork.c:2088
 SYSC_clone+0xf6/0x110 kernel/fork.c:2195
 SyS_clone+0x77/0xa0 kernel/fork.c:2189
 do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x3d/0xa2
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