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BUG: KMSAN: uninit-value in rcu_segcblist_ready_cbs+0xab/0xe0 kernel/rcu/rcu_segcblist.c:94
CPU: 0 PID: 15756 Comm: syz-executor3 Not tainted 4.17.0-rc5+ #103
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:686
 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+0x1b20/0x2a00 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+0xc03/0x15d0 kernel/time/hrtimer.c:1460
 hrtimer_interrupt+0x451/0x13c0 kernel/time/hrtimer.c:1518
 local_apic_timer_interrupt+0x66/0x230 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:__msan_poison_alloca+0x0/0x1d0 mm/kmsan/kmsan_instr.c:568
RSP: 0018:ffff8801caa4f360 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
RAX: ffff88017eacf728 RBX: ffffffff8191febe RCX: ffffffff8191febe
RDX: ffffffff8acac540 RSI: 0000000000000001 RDI: ffff8801caa4f728
RBP: ffff8801caa4f820 R08: 0000000001080020 R09: 0000000000000002
R10: 00000000014280c2 R11: 0000000000000000 R12: ffff8801b62807b8
R13: 0000000000000000 R14: 0000000000000001 R15: ffff8801caa4f9f8
 __alloc_pages_nodemask+0x7be/0x5dc0 mm/page_alloc.c:4371
 alloc_pages_current+0x6b1/0x970 mm/mempolicy.c:2093
 alloc_pages include/linux/gfp.h:494 [inline]
 __page_cache_alloc+0x95/0x320 mm/filemap.c:946
 pagecache_get_page+0x52b/0x1450 mm/filemap.c:1577
 find_or_create_page include/linux/pagemap.h:322 [inline]
 aio_setup_ring fs/aio.c:493 [inline]
 ioctx_alloc+0xef7/0x2c60 fs/aio.c:775
 __do_sys_io_setup fs/aio.c:1368 [inline]
 __se_sys_io_setup+0x16f/0x490 fs/aio.c:1351
 __x64_sys_io_setup+0x92/0xc0 fs/aio.c:1351
 do_syscall_64+0x152/0x230 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x455a09
RSP: 002b:00007f87a6594c68 EFLAGS: 00000246 ORIG_RAX: 00000000000000ce
RAX: ffffffffffffffda RBX: 00007f87a65956d4 RCX: 0000000000455a09
RDX: 0000000000000000 RSI: 0000000020f69000 RDI: 0000000000000fff
RBP: 000000000072bea0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 000000000000018d R14: 00000000006f75d8 R15: 0000000000000000

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:529
 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+0x2d91/0x38d0 kernel/exit.c:887
 do_group_exit+0x1a0/0x360 kernel/exit.c:970
 get_signal+0xfcb/0x1f40 kernel/signal.c:2482
 do_signal+0xb8/0x1cf0 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+0xe9/0x700 arch/x86/entry/common.c:265
 do_syscall_64+0x1af/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+0x3ef/0x970 mm/mmap.c:3094
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