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BUG: KMSAN: uninit-value in rcu_segcblist_ready_cbs+0xab/0xe0 kernel/rcu/rcu_segcblist.c:94
CPU: 0 PID: 28067 Comm: syz-executor6 Not tainted 4.17.0+ #3
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+0x149/0x260 mm/kmsan/kmsan.c:1084
 __msan_warning_32+0x6e/0xc0 mm/kmsan/kmsan_instr.c:620
 rcu_segcblist_ready_cbs+0xab/0xe0 kernel/rcu/rcu_segcblist.c:94
 __rcu_pending kernel/rcu/tree.c:3367 [inline]
 rcu_pending kernel/rcu/tree.c:3401 [inline]
 rcu_check_callbacks+0x13c3/0x2ae0 kernel/rcu/tree.c:2763
 update_process_times+0x132/0x1a0 kernel/time/timer.c:1636
 tick_sched_handle kernel/time/tick-sched.c:164 [inline]
 tick_sched_timer+0x3ba/0x520 kernel/time/tick-sched.c:1274
 __run_hrtimer kernel/time/hrtimer.c:1398 [inline]
 __hrtimer_run_queues+0xc54/0x1630 kernel/time/hrtimer.c:1460
 hrtimer_interrupt+0x451/0x13c0 kernel/time/hrtimer.c:1518
 local_apic_timer_interrupt+0x6b/0x250 arch/x86/kernel/apic/apic.c:1025
 smp_apic_timer_interrupt+0x5a/0x90 arch/x86/kernel/apic/apic.c:1053
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:863
 </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_clear_user_page+0xce/0xf0 mm/kmsan/kmsan.c:860
RSP: 0018:ffff880173f4fa70 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
RAX: 0000000000000000 RBX: ffffea0006b4c3c0 RCX: 0000000000000000
RDX: ffff880123a0a000 RSI: ffff880000000000 RDI: ffff880123a0b000
RBP: ffff880173f4fa98 R08: aaaaaaaaaaaab000 R09: 0000000000000002
R10: 0000000000000000 R11: 0000000000000000 R12: ffffea0006b4c3c0
R13: 0000000000000000 R14: ffff8801cab4d7c0 R15: 0000000000000246
 clear_user_highpage include/linux/highmem.h:141 [inline]
 clear_huge_page+0xb47/0xd10 mm/memory.c:4619
 __do_huge_pmd_anonymous_page mm/huge_memory.c:570 [inline]
 do_huge_pmd_anonymous_page+0xf86/0x2540 mm/huge_memory.c:728
 create_huge_pmd mm/memory.c:3854 [inline]
 __handle_mm_fault mm/memory.c:4058 [inline]
 handle_mm_fault+0x44da/0x7ec0 mm/memory.c:4124
 __do_page_fault+0xec6/0x1a10 arch/x86/mm/fault.c:1400
 do_page_fault+0xb7/0x250 arch/x86/mm/fault.c:1477
 page_fault+0x1e/0x30 arch/x86/entry/entry_64.S:1160
RIP: 0033:0x4076ca
RSP: 002b:0000000000a3e940 EFLAGS: 00010246
RAX: 0000000020c67000 RBX: 0000000000000000 RCX: 000000000000000a
RDX: 22e3d43cd35b9f37 RSI: 0000000000000000 RDI: 0000000001850848
RBP: 0000000000000001 R08: 0000000000000000 R09: 00000000007304b0
R10: 0000000000a3e940 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000002 R14: 000000000072bea0 R15: 0000000000077866

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:685
 __msan_chain_origin+0x69/0xc0 mm/kmsan/kmsan_instr.c:464
 rcu_segcblist_enqueue+0x275/0x2d0 kernel/rcu/rcu_segcblist.c:151
 __call_rcu+0x227/0xef0 kernel/rcu/tree.c:3057
 call_rcu_sched+0x32/0x40 kernel/rcu/tree.c:3097
 release_task+0x24b9/0x2530 kernel/exit.c:223
 exit_notify kernel/exit.c:736 [inline]
 do_exit+0x2e11/0x3930 kernel/exit.c:887
 do_group_exit+0x1a0/0x360 kernel/exit.c:970
 get_signal+0x1405/0x1ec0 kernel/signal.c:2482
 do_signal+0xb8/0x1d20 arch/x86/kernel/signal.c:810
 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+0xe9/0x710 arch/x86/entry/common.c:265
 do_syscall_64+0x1ad/0x230 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
Local variable description: ----ac@__alloc_pages_nodemask
Variable was created at:
 __alloc_pages_nodemask+0x196/0x5cc0 mm/page_alloc.c:4355
 alloc_pages_current+0x6b1/0x970 mm/mempolicy.c:2093
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