audit: type=1400 audit(1575302664.929:86220): avc:  denied  { sys_admin } for  pid=22283 comm="syz-executor.3" capability=21  scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=cap_userns permissive=1
audit: type=1400 audit(1575302664.959:86221): avc:  denied  { dac_override } for  pid=22283 comm="syz-executor.3" capability=1  scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=cap_userns permissive=1
==================================================================
BUG: KASAN: slab-out-of-bounds in __ptr_ring_produce include/linux/ptr_ring.h:107 [inline]
BUG: KASAN: slab-out-of-bounds in ptr_ring_produce include/linux/ptr_ring.h:130 [inline]
BUG: KASAN: slab-out-of-bounds in skb_array_produce include/linux/skb_array.h:48 [inline]
BUG: KASAN: slab-out-of-bounds in tun_net_xmit+0x10b8/0x1180 drivers/net/tun.c:920
Read of size 8 at addr ffff8801d262a660 by task syz-executor.1/2082

CPU: 1 PID: 2082 Comm: syz-executor.1 Not tainted 4.9.141+ #23
 ffff8801db7074a0 ffffffff81b42e79 ffffea0007498a00 ffff8801d262a660
 0000000000000000 ffff8801d262a660 ffff8801a744c108 ffff8801db7074d8
 ffffffff815009b8 ffff8801d262a660 0000000000000008 0000000000000000
Call Trace:
 <IRQ> 
 [<ffffffff81b42e79>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81b42e79>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff815009b8>] print_address_description+0x6c/0x234 mm/kasan/report.c:256
 [<ffffffff81500dc2>] kasan_report_error mm/kasan/report.c:355 [inline]
 [<ffffffff81500dc2>] kasan_report.cold.6+0x242/0x2fe mm/kasan/report.c:412
 [<ffffffff814f3074>] __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433
 [<ffffffff81ed4ad8>] __ptr_ring_produce include/linux/ptr_ring.h:107 [inline]
 [<ffffffff81ed4ad8>] ptr_ring_produce include/linux/ptr_ring.h:130 [inline]
 [<ffffffff81ed4ad8>] skb_array_produce include/linux/skb_array.h:48 [inline]
 [<ffffffff81ed4ad8>] tun_net_xmit+0x10b8/0x1180 drivers/net/tun.c:920
 [<ffffffff82314c67>] __netdev_start_xmit include/linux/netdevice.h:4069 [inline]
 [<ffffffff82314c67>] netdev_start_xmit include/linux/netdevice.h:4078 [inline]
 [<ffffffff82314c67>] xmit_one net/core/dev.c:2977 [inline]
 [<ffffffff82314c67>] dev_hard_start_xmit+0x197/0x8b0 net/core/dev.c:2993
 [<ffffffff82395173>] sch_direct_xmit+0x2b3/0x580 net/sched/sch_generic.c:182
 [<ffffffff82316bae>] __dev_xmit_skb net/core/dev.c:3173 [inline]
 [<ffffffff82316bae>] __dev_queue_xmit+0x152e/0x1b90 net/core/dev.c:3441
 [<ffffffff82317227>] dev_queue_xmit+0x17/0x20 net/core/dev.c:3506
 [<ffffffff82691981>] neigh_hh_output include/net/neighbour.h:468 [inline]
 [<ffffffff82691981>] dst_neigh_output include/net/dst.h:468 [inline]
 [<ffffffff82691981>] ip6_finish_output2+0x1161/0x1d10 net/ipv6/ip6_output.c:119
 [<ffffffff826a1e74>] ip6_finish_output+0x334/0x980 net/ipv6/ip6_output.c:145
 [<ffffffff826a26aa>] NF_HOOK_COND include/linux/netfilter.h:246 [inline]
 [<ffffffff826a26aa>] ip6_output+0x1ea/0x6d0 net/ipv6/ip6_output.c:162
 [<ffffffff8271dbae>] dst_output include/net/dst.h:507 [inline]
 [<ffffffff8271dbae>] NF_HOOK_THRESH include/linux/netfilter.h:232 [inline]
 [<ffffffff8271dbae>] NF_HOOK include/linux/netfilter.h:255 [inline]
 [<ffffffff8271dbae>] mld_sendpack+0xa1e/0xf80 net/ipv6/mcast.c:1659
 [<ffffffff827252ba>] mld_send_cr net/ipv6/mcast.c:1955 [inline]
 [<ffffffff827252ba>] mld_ifc_timer_expire+0x3ba/0x7b0 net/ipv6/mcast.c:2455
 [<ffffffff81262a43>] call_timer_fn+0x163/0x6e0 kernel/time/timer.c:1319
 [<ffffffff812631f4>] expire_timers+0x234/0x580 kernel/time/timer.c:1359
 [<ffffffff81263748>] __run_timers kernel/time/timer.c:1674 [inline]
 [<ffffffff81263748>] run_timer_softirq+0x208/0x5e0 kernel/time/timer.c:1687
 [<ffffffff8281cb9e>] __do_softirq+0x20e/0x964 kernel/softirq.c:288
 [<ffffffff810efdbc>] invoke_softirq kernel/softirq.c:368 [inline]
 [<ffffffff810efdbc>] irq_exit+0x11c/0x150 kernel/softirq.c:409
 [<ffffffff8281b771>] exiting_irq arch/x86/include/asm/apic.h:669 [inline]
 [<ffffffff8281b771>] smp_apic_timer_interrupt+0x81/0xb0 arch/x86/kernel/apic/apic.c:962
 [<ffffffff8281902d>] apic_timer_interrupt+0x9d/0xb0 arch/x86/entry/entry_64.S:648
 <EOI> 
 [<ffffffff82818214>] retint_kernel+0x1b/0x2d
 [<ffffffff812270c8>] vprintk_emit+0x448/0x790 kernel/printk/printk.c:1908
 [<ffffffff81227438>] vprintk+0x28/0x30 kernel/printk/printk.c:1918
 [<ffffffff8122745d>] vprintk_default+0x1d/0x30 kernel/printk/printk.c:1919
 [<ffffffff81402f9f>] vprintk_func kernel/printk/internal.h:36 [inline]
 [<ffffffff81402f9f>] printk+0xaf/0xd7 kernel/printk/printk.c:1980
 [<ffffffff814078dc>] audit_printk_skb.cold.12+0x3f/0x4e kernel/audit.c:397
 [<ffffffff812f1ca4>] audit_log_end+0x3b4/0x600 kernel/audit.c:2016
 [<ffffffff81a47a06>] common_lsm_audit+0x546/0x1b40 security/lsm_audit.c:448
 [<ffffffff819ec79f>] slow_avc_audit+0x17f/0x210 security/selinux/avc.c:773
 [<ffffffff819fac91>] avc_audit security/selinux/include/avc.h:140 [inline]
 [<ffffffff819fac91>] cred_has_capability+0x251/0x2e0 security/selinux/hooks.c:1668
 [<ffffffff819fadb6>] selinux_capable+0x36/0x40 security/selinux/hooks.c:2178
 [<ffffffff819e2d78>] security_capable+0x88/0xc0 security/security.c:189
 [<ffffffff810fa7c4>] ns_capable_common+0xd4/0x150 kernel/capability.c:373
 [<ffffffff810fa862>] ns_capable+0x22/0x30 kernel/capability.c:395
 [<ffffffff81577503>] may_mount fs/namespace.c:1687 [inline]
 [<ffffffff81577503>] SYSC_umount fs/namespace.c:1716 [inline]
 [<ffffffff81577503>] SyS_umount+0x113/0xcf0 fs/namespace.c:1706
 [<ffffffff81006311>] do_syscall_32_irqs_on arch/x86/entry/common.c:328 [inline]
 [<ffffffff81006311>] do_fast_syscall_32+0x2f1/0xa10 arch/x86/entry/common.c:390
 [<ffffffff82818de0>] entry_SYSENTER_compat+0x90/0xa2 arch/x86/entry/entry_64_compat.S:137

Allocated by task 22298:
 save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:57
 save_stack mm/kasan/kasan.c:505 [inline]
 set_track mm/kasan/kasan.c:517 [inline]
 kasan_kmalloc.part.1+0x62/0xf0 mm/kasan/kasan.c:609
 kasan_kmalloc+0xaf/0xc0 mm/kasan/kasan.c:594
 __kmalloc+0x12f/0x310 mm/slub.c:3741
 kmalloc_array include/linux/slab.h:582 [inline]
 kcalloc include/linux/slab.h:593 [inline]
 __ptr_ring_init_queue_alloc include/linux/ptr_ring.h:356 [inline]
 ptr_ring_resize_multiple include/linux/ptr_ring.h:445 [inline]
 skb_array_resize_multiple include/linux/skb_array.h:169 [inline]
 tun_queue_resize drivers/net/tun.c:2523 [inline]
 tun_device_event+0x3e0/0xa00 drivers/net/tun.c:2541
 notifier_call_chain+0xb4/0x1d0 kernel/notifier.c:93
 __raw_notifier_call_chain kernel/notifier.c:394 [inline]
 raw_notifier_call_chain+0x2d/0x40 kernel/notifier.c:401
 call_netdevice_notifiers_info+0x55/0x70 net/core/dev.c:1647
 call_netdevice_notifiers+0x70/0xa0 net/core/dev.c:1663
 do_setlink+0xc55/0x2ef0 net/core/rtnetlink.c:2052
 rtnl_group_changelink net/core/rtnetlink.c:2423 [inline]
 rtnl_newlink+0xbd0/0x1550 net/core/rtnetlink.c:2571
 rtnetlink_rcv_msg+0x49c/0x650 net/core/rtnetlink.c:4078
 netlink_rcv_skb+0x145/0x370 net/netlink/af_netlink.c:2365
 rtnetlink_rcv+0x2a/0x40 net/core/rtnetlink.c:4084
 netlink_unicast_kernel net/netlink/af_netlink.c:1285 [inline]
 netlink_unicast+0x4d8/0x6d0 net/netlink/af_netlink.c:1311
 netlink_sendmsg+0x694/0xc30 net/netlink/af_netlink.c:1859
 sock_sendmsg_nosec net/socket.c:648 [inline]
 sock_sendmsg+0xbb/0x110 net/socket.c:658
 ___sys_sendmsg+0x6fc/0x840 net/socket.c:1982
 __sys_sendmsg+0xd9/0x190 net/socket.c:2016
 C_SYSC_sendmsg net/compat.c:736 [inline]
 compat_SyS_sendmsg+0x2a/0x40 net/compat.c:734
 do_syscall_32_irqs_on arch/x86/entry/common.c:328 [inline]
 do_fast_syscall_32+0x2f1/0xa10 arch/x86/entry/common.c:390
 entry_SYSENTER_compat+0x90/0xa2 arch/x86/entry/entry_64_compat.S:137

Freed by task 2084:
 save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:57
 save_stack mm/kasan/kasan.c:505 [inline]
 set_track mm/kasan/kasan.c:517 [inline]
 kasan_slab_free+0xac/0x190 mm/kasan/kasan.c:582
 slab_free_hook mm/slub.c:1355 [inline]
 slab_free_freelist_hook mm/slub.c:1377 [inline]
 slab_free mm/slub.c:2958 [inline]
 kfree+0xfb/0x310 mm/slub.c:3878
 skb_free_head+0x8b/0xb0 net/core/skbuff.c:580
 skb_release_data+0x338/0x3d0 net/core/skbuff.c:611
 skb_release_all+0x4a/0x60 net/core/skbuff.c:670
 __kfree_skb net/core/skbuff.c:684 [inline]
 kfree_skb+0xcc/0x340 net/core/skbuff.c:705
 audit_hold_skb+0x63/0x70 kernel/audit.c:383
 audit_printk_skb+0x7a/0xd0 kernel/audit.c:402
 audit_log_end+0x3b4/0x600 kernel/audit.c:2016
 common_lsm_audit+0x546/0x1b40 security/lsm_audit.c:448
 slow_avc_audit+0x17f/0x210 security/selinux/avc.c:773
 avc_audit security/selinux/include/avc.h:140 [inline]
 cred_has_capability+0x251/0x2e0 security/selinux/hooks.c:1668
 selinux_capable+0x36/0x40 security/selinux/hooks.c:2178
 security_capable+0x88/0xc0 security/security.c:189
 ns_capable_common+0xd4/0x150 kernel/capability.c:373
 ns_capable+0x22/0x30 kernel/capability.c:395
 may_mount fs/namespace.c:1687 [inline]
 SYSC_umount fs/namespace.c:1716 [inline]
 SyS_umount+0x113/0xcf0 fs/namespace.c:1706
 do_syscall_32_irqs_on arch/x86/entry/common.c:328 [inline]
 do_fast_syscall_32+0x2f1/0xa10 arch/x86/entry/common.c:390
 entry_SYSENTER_compat+0x90/0xa2 arch/x86/entry/entry_64_compat.S:137

The buggy address belongs to the object at ffff8801d262a200
 which belongs to the cache kmalloc-2048 of size 2048
The buggy address is located 1120 bytes inside of
 2048-byte region [ffff8801d262a200, ffff8801d262aa00)
The buggy address belongs to the page:
page:ffffea0007498a00 count:1 mapcount:0 mapping:          (null) index:0x0 compound_mapcount: 0
flags: 0x4000000000004080(slab|head)
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801d262a500: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8801d262a580: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8801d262a600: 00 00 00 00 00 00 00 00 00 00 00 00 fc fc fc fc
                                                       ^
 ffff8801d262a680: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8801d262a700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================