==================================================================
BUG: KMSAN: uninit-value in rcu_cblist_dequeue+0x1bb/0x290 kernel/rcu/rcu_segcblist.c:54
CPU: 0 PID: 4579 Comm: syz-executor7 Not tainted 4.16.0+ #87
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <IRQ>
 __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_cblist_dequeue+0x1bb/0x290 kernel/rcu/rcu_segcblist.c:54
 rcu_do_batch kernel/rcu/tree.c:2671 [inline]
 invoke_rcu_callbacks kernel/rcu/tree.c:2933 [inline]
 __rcu_process_callbacks kernel/rcu/tree.c:2900 [inline]
 rcu_process_callbacks+0x15cd/0x2070 kernel/rcu/tree.c:2917
 __do_softirq+0x56d/0x93d 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:541
 smp_apic_timer_interrupt+0x64/0x90 arch/x86/kernel/apic/apic.c:1055
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:857
 </IRQ>
RIP: 0010:native_restore_fl arch/x86/include/asm/irqflags.h:37 [inline]
RIP: 0010:arch_local_irq_restore arch/x86/include/asm/irqflags.h:78 [inline]
RIP: 0010:kmsan_kmalloc+0xc6/0x100 mm/kmsan/kmsan.c:316
RSP: 0018:ffff8801540cfb20 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff12
RAX: 0000000000000246 RBX: ffff8801d90f4000 RCX: 0000000000000401
RDX: 0000000000000400 RSI: ffffea000b165bc8 RDI: ffff8801d90f4000
RBP: ffff8801540cfb60 R08: 00000000010000c0 R09: 0000000000000002
R10: 0000000000000000 R11: ffff8801540c0000 R12: ffff8801dc308d80
R13: ffff880197103b00 R14: 0000000000001000 R15: 00000000014000c0
 kmsan_slab_alloc+0x11/0x20 mm/kmsan/kmsan.c:321
 slab_post_alloc_hook mm/slab.h:445 [inline]
 slab_alloc_node mm/slub.c:2737 [inline]
 slab_alloc mm/slub.c:2745 [inline]
 kmem_cache_alloc+0x692/0xb90 mm/slub.c:2750
 getname_flags+0x12a/0xaa0 fs/namei.c:138
 user_path_at_empty+0xbb/0x140 fs/namei.c:2569
 user_path_at include/linux/namei.h:57 [inline]
 vfs_statx fs/stat.c:185 [inline]
 vfs_lstat include/linux/fs.h:3080 [inline]
 SYSC_newlstat+0xd1/0x330 fs/stat.c:350
 SyS_newlstat+0x46/0x70 fs/stat.c:344
 do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x3d/0xa2
RIP: 0033:0x454d55
RSP: 002b:0000000000a3d9d8 EFLAGS: 00000246 ORIG_RAX: 0000000000000006
RAX: ffffffffffffffda RBX: 000000000000001a RCX: 0000000000454d55
RDX: 0000000000a3d9f0 RSI: 0000000000a3d9f0 RDI: 0000000000a3da80
RBP: 0000000000a3f790 R08: 0000000000000000 R09: 000000000000000f
R10: 000000000000000a R11: 0000000000000246 R12: 000000000151d940
R13: 0000000000000000 R14: 0000000000000175 R15: 000000000001bef1

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_extract_done_cbs+0x3f7/0x5e0 kernel/rcu/rcu_segcblist.c:215
 rcu_do_batch kernel/rcu/tree.c:2667 [inline]
 invoke_rcu_callbacks kernel/rcu/tree.c:2933 [inline]
 __rcu_process_callbacks kernel/rcu/tree.c:2900 [inline]
 rcu_process_callbacks+0x159b/0x2070 kernel/rcu/tree.c:2917
 __do_softirq+0x56d/0x93d kernel/softirq.c:285
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+0x24c/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
 free_pid+0x441/0x450 kernel/pid.c:156
 __change_pid kernel/pid.c:294 [inline]
 detach_pid+0x35a/0x370 kernel/pid.c:299
 __unhash_process kernel/exit.c:75 [inline]
 __exit_signal kernel/exit.c:156 [inline]
 release_task+0x10a0/0x2530 kernel/exit.c:200
 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: ----name.i@proc_flush_task
Variable was created at:
 proc_flush_task+0x60/0x810 fs/proc/base.c:3119
 release_task+0xa1/0x2530 kernel/exit.c:196
==================================================================