syzbot

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BUG: KASAN: use-after-free in hlist_add_head include/linux/list.h:673 [inline]
BUG: KASAN: use-after-free in enqueue_timer kernel/time/timer.c:520 [inline]
BUG: KASAN: use-after-free in __mod_timer kernel/time/timer.c:1021 [inline]
BUG: KASAN: use-after-free in mod_timer+0x11d3/0x15b0 kernel/time/timer.c:1071
Write of size 8 at addr ffff8801d42a4188 by task ksoftirqd/1/16

CPU: 1 PID: 16 Comm: ksoftirqd/1 Not tainted 4.13.0+ #73
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:16 [inline]
 dump_stack+0x194/0x257 lib/dump_stack.c:52
 print_address_description+0x73/0x250 mm/kasan/report.c:252
 kasan_report_error mm/kasan/report.c:351 [inline]
 kasan_report+0x24e/0x340 mm/kasan/report.c:409
 __asan_report_store8_noabort+0x17/0x20 mm/kasan/report.c:435
 hlist_add_head include/linux/list.h:673 [inline]
 enqueue_timer kernel/time/timer.c:520 [inline]
 __mod_timer kernel/time/timer.c:1021 [inline]
 mod_timer+0x11d3/0x15b0 kernel/time/timer.c:1071
 sk_reset_timer+0x22/0x50 net/core/sock.c:2664
 inet_csk_reset_xmit_timer include/net/inet_connection_sock.h:243 [inline]
 tcp_v4_err+0x16f7/0x17e0 net/ipv4/tcp_ipv4.c:492
 icmp_socket_deliver+0x21a/0x440 net/ipv4/icmp.c:771
 icmp_unreach+0x3d0/0xc50 net/ipv4/icmp.c:879
 icmp_rcv+0x6b6/0x1250 net/ipv4/icmp.c:1060
 ip_local_deliver_finish+0x2e2/0xba0 net/ipv4/ip_input.c:216
 NF_HOOK include/linux/netfilter.h:249 [inline]
 ip_local_deliver+0x1ce/0x6e0 net/ipv4/ip_input.c:257
 dst_input include/net/dst.h:478 [inline]
 ip_rcv_finish+0x8db/0x19c0 net/ipv4/ip_input.c:397
 NF_HOOK include/linux/netfilter.h:249 [inline]
 ip_rcv+0xc3f/0x17d0 net/ipv4/ip_input.c:488
 __netif_receive_skb_core+0x19af/0x33d0 net/core/dev.c:4418
 __netif_receive_skb+0x2c/0x1b0 net/core/dev.c:4456
 process_backlog+0x203/0x740 net/core/dev.c:5132
 napi_poll net/core/dev.c:5530 [inline]
 net_rx_action+0x792/0x1910 net/core/dev.c:5596
 __do_softirq+0x2bb/0xbd0 kernel/softirq.c:284
 run_ksoftirqd+0x50/0x100 kernel/softirq.c:676
 smpboot_thread_fn+0x489/0x850 kernel/smpboot.c:164
 kthread+0x39c/0x470 kernel/kthread.c:231
 ret_from_fork+0x2a/0x40 arch/x86/entry/entry_64.S:431

Allocated by task 22518:
 save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59
 save_stack+0x43/0xd0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_kmalloc+0xad/0xe0 mm/kasan/kasan.c:551
 __do_kmalloc_node mm/slab.c:3689 [inline]
 __kmalloc_node+0x47/0x70 mm/slab.c:3696
 kmalloc_node include/linux/slab.h:535 [inline]
 kvmalloc_node+0x64/0xd0 mm/util.c:397
 kvmalloc include/linux/mm.h:528 [inline]
 kvzalloc include/linux/mm.h:536 [inline]
 alloc_netdev_mqs+0x16e/0xed0 net/core/dev.c:8011
 tun_set_iff drivers/net/tun.c:2022 [inline]
 __tun_chr_ioctl+0x12be/0x3d40 drivers/net/tun.c:2276
 tun_chr_ioctl+0x2a/0x40 drivers/net/tun.c:2521
 vfs_ioctl fs/ioctl.c:45 [inline]
 do_vfs_ioctl+0x1b1/0x1530 fs/ioctl.c:685
 SYSC_ioctl fs/ioctl.c:700 [inline]
 SyS_ioctl+0x8f/0xc0 fs/ioctl.c:691
 entry_SYSCALL_64_fastpath+0x1f/0xbe

Freed by task 22518:
 save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59
 save_stack+0x43/0xd0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_slab_free+0x71/0xc0 mm/kasan/kasan.c:524
 __cache_free mm/slab.c:3503 [inline]
 kfree+0xca/0x250 mm/slab.c:3820
 kvfree+0x36/0x60 mm/util.c:416
 netdev_freemem net/core/dev.c:7963 [inline]
 free_netdev+0x2cf/0x360 net/core/dev.c:8125
 tun_set_iff drivers/net/tun.c:2105 [inline]
 __tun_chr_ioctl+0x2cff/0x3d40 drivers/net/tun.c:2276
 tun_chr_ioctl+0x2a/0x40 drivers/net/tun.c:2521
 vfs_ioctl fs/ioctl.c:45 [inline]
 do_vfs_ioctl+0x1b1/0x1530 fs/ioctl.c:685
 SYSC_ioctl fs/ioctl.c:700 [inline]
 SyS_ioctl+0x8f/0xc0 fs/ioctl.c:691
 entry_SYSCALL_64_fastpath+0x1f/0xbe

The buggy address belongs to the object at ffff8801d42a0d80
 which belongs to the cache kmalloc-16384 of size 16384
The buggy address is located 13320 bytes inside of
 16384-byte region [ffff8801d42a0d80, ffff8801d42a4d80)
The buggy address belongs to the page:
page:ffffea000750a800 count:1 mapcount:0 mapping:ffff8801d42a0d80 index:0x0 compound_mapcount: 0
flags: 0x200000000008100(slab|head)
raw: 0200000000008100 ffff8801d42a0d80 0000000000000000 0000000100000001
raw: ffffea000711b620 ffffea000754ea20 ffff8801dac02200 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801d42a4080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8801d42a4100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8801d42a4180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                      ^
 ffff8801d42a4200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8801d42a4280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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