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BUG: KASAN: stack-out-of-bounds in csd_lock_record+0xd2/0xe0 kernel/smp.c:119
Read of size 8 at addr ffffc900016775b8 by task syz-executor.5/23673

CPU: 0 PID: 23673 Comm: syz-executor.5 Not tainted 5.8.0-rc3-next-20200703-syzkaller #0
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+0x18f/0x20d lib/dump_stack.c:118
 print_address_description.constprop.0.cold+0x5/0x436 mm/kasan/report.c:383
 __kasan_report mm/kasan/report.c:513 [inline]
 kasan_report.cold+0x1f/0x37 mm/kasan/report.c:530
 csd_lock_record+0xd2/0xe0 kernel/smp.c:119
 flush_smp_call_function_queue+0x285/0x730 kernel/smp.c:391
 __sysvec_call_function_single+0x98/0x490 arch/x86/kernel/smp.c:248
 asm_call_on_stack+0xf/0x20 arch/x86/entry/entry_64.S:706
 </IRQ>
 __run_on_irqstack arch/x86/include/asm/irq_stack.h:22 [inline]
 run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:48 [inline]
 sysvec_call_function_single+0xe0/0x120 arch/x86/kernel/smp.c:243
 asm_sysvec_call_function_single+0x12/0x20 arch/x86/include/asm/idtentry.h:604
RIP: 0010:unwind_next_frame+0x42/0x1f90 arch/x86/kernel/unwind_orc.c:424
Code: 81 ec a0 00 00 00 48 c7 44 24 40 b3 8a b5 41 48 8d 5c 24 40 48 c7 44 24 48 68 a0 67 89 48 c1 eb 03 48 c7 44 24 50 e0 3b 33 81 <48> 8d 14 03 c7 02 f1 f1 f1 f1 c7 42 04 00 f3 f3 f3 48 89 fa 65 48
RSP: 0018:ffffc900020e6e28 EFLAGS: 00000a02
RAX: dffffc0000000000 RBX: 1ffff9200041cdcd RCX: 0000000000000000
RDX: 1ffff9200041ce0f RSI: ffffffff86e108de RDI: ffffc900020e6f00
RBP: ffffc900020e6f88 R08: ffffffff8b84c1ca R09: 0000000000000001
R10: 000000000007201e R11: 0000000000000001 R12: ffffc900020e6fb8
R13: 0000000000000000 R14: ffff8880904ac140 R15: ffffc900020e6f00
 arch_stack_walk+0x81/0xf0 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x8c/0xc0 kernel/stacktrace.c:123
 save_stack+0x1b/0x40 mm/kasan/common.c:48
 set_track mm/kasan/common.c:56 [inline]
 __kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:494
 slab_post_alloc_hook mm/slab.h:535 [inline]
 slab_alloc_node mm/slab.c:3258 [inline]
 kmem_cache_alloc_node+0x14b/0x580 mm/slab.c:3578
 __alloc_skb+0x71/0x550 net/core/skbuff.c:198
 alloc_skb include/linux/skbuff.h:1084 [inline]
 tcp_v6_send_response+0x234/0x20c0 net/ipv6/tcp_ipv6.c:877
 tcp_v6_send_reset+0x4fd/0x13d0 net/ipv6/tcp_ipv6.c:1070
 tcp_v6_rcv+0x1e63/0x3470 net/ipv6/tcp_ipv6.c:1708
 ip6_protocol_deliver_rcu+0x2e8/0x1670 net/ipv6/ip6_input.c:433
 ip6_input_finish+0x7f/0x160 net/ipv6/ip6_input.c:474
 NF_HOOK include/linux/netfilter.h:307 [inline]
 NF_HOOK include/linux/netfilter.h:301 [inline]
 ip6_input+0x9c/0xd0 net/ipv6/ip6_input.c:483
 dst_input include/net/dst.h:441 [inline]
 ip6_rcv_finish net/ipv6/ip6_input.c:76 [inline]
 NF_HOOK include/linux/netfilter.h:307 [inline]
 NF_HOOK include/linux/netfilter.h:301 [inline]
 ipv6_rcv+0x28e/0x3c0 net/ipv6/ip6_input.c:307
 __netif_receive_skb_one_core+0x114/0x180 net/core/dev.c:5287
 __netif_receive_skb+0x27/0x1c0 net/core/dev.c:5401
 netif_receive_skb_internal net/core/dev.c:5503 [inline]
 netif_receive_skb+0x159/0x990 net/core/dev.c:5562
 tun_rx_batched.isra.0+0x460/0x720 drivers/net/tun.c:1518
 tun_get_user+0x23b2/0x35b0 drivers/net/tun.c:1972
 tun_chr_write_iter+0xba/0x151 drivers/net/tun.c:2001
 call_write_iter include/linux/fs.h:1877 [inline]
 new_sync_write+0x422/0x650 fs/read_write.c:484
 __vfs_write+0xc9/0x100 fs/read_write.c:497
 vfs_write+0x268/0x5d0 fs/read_write.c:559
 ksys_write+0x12d/0x250 fs/read_write.c:612
 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:367
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x416661
Code: Bad RIP value.
RSP: 002b:00007f59a4110c60 EFLAGS: 00000293 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000509660 RCX: 0000000000416661
RDX: 000000000000004a RSI: 0000000020000180 RDI: 00000000000000f0
RBP: 000000000078c0e0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000293 R12: 00000000ffffffff
R13: 0000000000000bff R14: 00000000004ce559 R15: 00007f59a41116d4


Memory state around the buggy address:
 ffffc90001677480: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffffc90001677500: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffffc90001677580: f1 f1 f1 f1 00 00 00 00 f3 f3 f3 f3 00 00 00 00
                                           ^
 ffffc90001677600: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffffc90001677680: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
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