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BUG: KMSAN: uninit-value in rcu_segcblist_ready_cbs+0xab/0xe0 kernel/rcu/rcu_segcblist.c:94
CPU: 1 PID: 29826 Comm: syz-executor1 Not tainted 4.17.0+ #9
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:1125
 __msan_warning_32+0x70/0xc0 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:866
 </IRQ>
RIP: 0010:finish_lock_switch+0x38/0x50 kernel/sched/core.c:2626
RSP: 0018:ffff88002028fc20 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
RAX: ffff88021f2dac40 RBX: 0000000000000001 RCX: ffff880000000000
RDX: ffff88021f2dbc40 RSI: aaaaaaaaaaaab000 RDI: ffffea0000000000
RBP: ffff88002028fc38 R08: 0000000001080020 R09: 0000000000000002
R10: ffffffff7fffffff R11: ffffffff813553c0 R12: ffff88021fd3ec40
R13: ffff8801658688d8 R14: 0000000000000000 R15: ffff88021f2dac40
 finish_task_switch+0xde/0x270 kernel/sched/core.c:2725
 context_switch kernel/sched/core.c:2883 [inline]
 __schedule+0x66b/0x770 kernel/sched/core.c:3524
 schedule+0x1cc/0x2f0 kernel/sched/core.c:3568
 freezable_schedule include/linux/freezer.h:172 [inline]
 do_nanosleep+0x2c3/0x9c0 kernel/time/hrtimer.c:1689
 hrtimer_nanosleep kernel/time/hrtimer.c:1743 [inline]
 __do_sys_nanosleep kernel/time/hrtimer.c:1775 [inline]
 __se_sys_nanosleep+0x4b3/0x6a0 kernel/time/hrtimer.c:1762
 __x64_sys_nanosleep+0x92/0xc0 kernel/time/hrtimer.c:1762
 do_syscall_64+0x15b/0x230 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x481251
RSP: 002b:0000000000a3e950 EFLAGS: 00000293 ORIG_RAX: 0000000000000023
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000481251
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000a3e960
RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000a3e940 R11: 0000000000000293 R12: 0000000000000000
R13: 0000000000000002 R14: 000000000072bea0 R15: 000000000006c139

Uninit was stored to memory at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:282 [inline]
 kmsan_save_stack mm/kmsan/kmsan.c:297 [inline]
 kmsan_internal_chain_origin+0x12b/0x210 mm/kmsan/kmsan.c:689
 __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: ----tlb.i@ldt_arch_exit_mmap
Variable was created at:
 ldt_arch_exit_mmap+0x46/0x160 arch/x86/kernel/ldt.c:302
 arch_exit_mmap arch/x86/include/asm/mmu_context.h:245 [inline]
 exit_mmap+0x410/0x980 mm/mmap.c:3094
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