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BUG: KASAN: alloca-out-of-bounds in tick_sched_handle+0x16d/0x180 kernel/time/tick-sched.c:171
Read of size 8 at addr ffff8801d88372d0 by task syzkaller268977/4622

CPU: 0 PID: 4622 Comm: syzkaller268977 Not tainted 4.16.0+ #17
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+0x1b9/0x294 lib/dump_stack.c:113
 print_address_description+0x6c/0x20b mm/kasan/report.c:256
 kasan_report_error mm/kasan/report.c:354 [inline]
 kasan_report.cold.7+0xac/0x2f5 mm/kasan/report.c:412
 __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433
 tick_sched_handle+0x16d/0x180 kernel/time/tick-sched.c:171
 tick_sched_timer+0x42/0x130 kernel/time/tick-sched.c:1179
 __run_hrtimer kernel/time/hrtimer.c:1337 [inline]
 __hrtimer_run_queues+0x3e3/0x10a0 kernel/time/hrtimer.c:1399
 hrtimer_interrupt+0x286/0x650 kernel/time/hrtimer.c:1457
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1025 [inline]
 smp_apic_timer_interrupt+0x15d/0x710 arch/x86/kernel/apic/apic.c:1050
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:862
 </IRQ>
RIP: 0010:kasan_unpoison_shadow+0x0/0x50 mm/kasan/kasan.c:51
RSP: 0018:ffff8801d88372f8 EFLAGS: 00000202 ORIG_RAX: ffffffffffffff13
RAX: ffff8801d8bb2240 RBX: ffffffff85f30c20 RCX: ffffffff85ec13ef
RDX: 0000000000000000 RSI: 00000000000000d0 RDI: ffff8801d8837240
RBP: ffff8801d8837300 R08: ffff8801d8bb2240 R09: fffffbfff15db292
R10: fffffbfff15db292 R11: ffffffff8aed9497 R12: 00000000ffffffea
R13: 0000000000000000 R14: 00000000ffffffea R15: ffff8801ba25e0c0
 rcu_lock_release include/linux/rcupdate.h:251 [inline]
 rcu_read_unlock include/linux/rcupdate.h:688 [inline]
 nfnetlink_rcv_msg+0x6af/0xfe0 net/netfilter/nfnetlink.c:196
 netlink_rcv_skb+0x172/0x440 net/netlink/af_netlink.c:2448
 nfnetlink_rcv+0x1fe/0x1ba0 net/netfilter/nfnetlink.c:513
 netlink_unicast_kernel net/netlink/af_netlink.c:1310 [inline]
 netlink_unicast+0x58b/0x740 net/netlink/af_netlink.c:1336
 netlink_sendmsg+0x9f0/0xfa0 net/netlink/af_netlink.c:1901
 sock_sendmsg_nosec net/socket.c:629 [inline]
 sock_sendmsg+0xd5/0x120 net/socket.c:639
 ___sys_sendmsg+0x805/0x940 net/socket.c:2117
 __sys_sendmsg+0x115/0x270 net/socket.c:2155
 SYSC_sendmsg net/socket.c:2164 [inline]
 SyS_sendmsg+0x29/0x30 net/socket.c:2162
 do_syscall_64+0x29e/0x9d0 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x447329
RSP: 002b:00007f6bc4d9cce8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00000000006ddc5c RCX: 0000000000447329
RDX: 0000000000000000 RSI: 0000000020498000 RDI: 00000000000003ff
RBP: 00000000006ddc58 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffea5a41b9f R14: 00007f6bc4d9d9c0 R15: 0000000000000005

The buggy address belongs to the page:
page:ffffea0007620dc0 count:0 mapcount:0 mapping:0000000000000000 index:0x0
flags: 0x2fffc0000000000()
raw: 02fffc0000000000 0000000000000000 0000000000000000 00000000ffffffff
raw: 0000000000000000 ffffea0007620101 0000000000000000 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801d8837180: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8801d8837200: 00 00 00 00 00 00 00 00 ca ca ca ca 00 00 00 00
>ffff8801d8837280: 00 00 00 00 00 00 00 00 cb cb cb cb 00 00 00 00
                                                 ^
 ffff8801d8837300: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8801d8837380: 00 00 00 00 00 00 00 f1 f1 f1 f1 f8 f2 f2 f2 f2
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