EXT4-fs (loop1): VFS: Can't find ext4 filesystem
selinux_nlmsg_perm: 8 callbacks suppressed
SELinux: unrecognized netlink message: protocol=0 nlmsg_type=10757 sclass=netlink_route_socket pig=3746 comm=syz-executor.4
EXT4-fs (loop1): VFS: Can't find ext4 filesystem
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BUG: KASAN: use-after-free in ____bpf_skb_change_head net/core/filter.c:2423 [inline]
BUG: KASAN: use-after-free in bpf_skb_change_head+0x4ea/0x600 net/core/filter.c:2419
Read of size 4 at addr ffff8881cf7aee78 by task syz-executor.0/3751

CPU: 0 PID: 3751 Comm: syz-executor.0 Not tainted 4.14.155-syzkaller #0
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0xe5/0x154 lib/dump_stack.c:58
 print_address_description+0x60/0x226 mm/kasan/report.c:187
 __kasan_report.cold+0x1a/0x41 mm/kasan/report.c:316
 ____bpf_skb_change_head net/core/filter.c:2423 [inline]
 bpf_skb_change_head+0x4ea/0x600 net/core/filter.c:2419
 ___bpf_prog_run+0x2478/0x5510 kernel/bpf/core.c:1095

Allocated by task 3658:
 save_stack mm/kasan/common.c:76 [inline]
 set_track mm/kasan/common.c:85 [inline]
 __kasan_kmalloc.part.0+0x53/0xc0 mm/kasan/common.c:501
 slab_post_alloc_hook mm/slab.h:439 [inline]
 slab_alloc_node mm/slub.c:2792 [inline]
 slab_alloc mm/slub.c:2800 [inline]
 kmem_cache_alloc+0xee/0x360 mm/slub.c:2805
 kmem_cache_alloc_node include/linux/slab.h:361 [inline]
 __alloc_skb+0xea/0x5c0 net/core/skbuff.c:193
 alloc_skb include/linux/skbuff.h:980 [inline]
 kobject_uevent_env+0x6d7/0xc60 lib/kobject_uevent.c:479
 netdev_queue_add_kobject net/core/net-sysfs.c:1341 [inline]
 netdev_queue_update_kobjects+0x2ba/0x380 net/core/net-sysfs.c:1355
 register_queue_kobjects net/core/net-sysfs.c:1397 [inline]
 netdev_register_kobject+0x228/0x31c net/core/net-sysfs.c:1603
 register_netdevice+0x83d/0xc90 net/core/dev.c:7668
 __ip_tunnel_create+0x311/0x470 net/ipv4/ip_tunnel.c:282
 ip_tunnel_init_net+0x281/0x540 net/ipv4/ip_tunnel.c:1033
 vti_init_net+0x2a/0x2f0 net/ipv4/ip_vti.c:488
 ops_init+0xad/0x3f0 net/core/net_namespace.c:118
 setup_net+0x259/0x550 net/core/net_namespace.c:295
 copy_net_ns+0x195/0x480 net/core/net_namespace.c:419
 create_new_namespaces+0x373/0x760 kernel/nsproxy.c:107
 unshare_nsproxy_namespaces+0xa5/0x1e0 kernel/nsproxy.c:206
 SYSC_unshare kernel/fork.c:2543 [inline]
 SyS_unshare+0x34e/0x6c0 kernel/fork.c:2493
 do_syscall_64+0x19b/0x520 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
 0xffffffffffffffff

Freed by task 3658:
 save_stack mm/kasan/common.c:76 [inline]
 set_track mm/kasan/common.c:85 [inline]
 __kasan_slab_free+0x164/0x210 mm/kasan/common.c:463
 slab_free_hook mm/slub.c:1407 [inline]
 slab_free_freelist_hook mm/slub.c:1458 [inline]
 slab_free mm/slub.c:3039 [inline]
 kmem_cache_free+0xd7/0x3b0 mm/slub.c:3055
 kfree_skbmem net/core/skbuff.c:586 [inline]
 kfree_skbmem+0xa0/0x110 net/core/skbuff.c:580
 __kfree_skb net/core/skbuff.c:646 [inline]
 consume_skb+0xe4/0x360 net/core/skbuff.c:705
 netlink_broadcast_filtered+0x2c0/0xa00 net/netlink/af_netlink.c:1488
 kobject_uevent_env+0x81f/0xc60 lib/kobject_uevent.c:495
 netdev_queue_add_kobject net/core/net-sysfs.c:1341 [inline]
 netdev_queue_update_kobjects+0x2ba/0x380 net/core/net-sysfs.c:1355
 register_queue_kobjects net/core/net-sysfs.c:1397 [inline]
 netdev_register_kobject+0x228/0x31c net/core/net-sysfs.c:1603
 register_netdevice+0x83d/0xc90 net/core/dev.c:7668
 __ip_tunnel_create+0x311/0x470 net/ipv4/ip_tunnel.c:282
 ip_tunnel_init_net+0x281/0x540 net/ipv4/ip_tunnel.c:1033
 vti_init_net+0x2a/0x2f0 net/ipv4/ip_vti.c:488
 ops_init+0xad/0x3f0 net/core/net_namespace.c:118
 setup_net+0x259/0x550 net/core/net_namespace.c:295
 copy_net_ns+0x195/0x480 net/core/net_namespace.c:419
 create_new_namespaces+0x373/0x760 kernel/nsproxy.c:107
 unshare_nsproxy_namespaces+0xa5/0x1e0 kernel/nsproxy.c:206
 SYSC_unshare kernel/fork.c:2543 [inline]
 SyS_unshare+0x34e/0x6c0 kernel/fork.c:2493
 do_syscall_64+0x19b/0x520 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
 0xffffffffffffffff

The buggy address belongs to the object at ffff8881cf7aedc0
 which belongs to the cache skbuff_head_cache of size 224
The buggy address is located 184 bytes inside of
 224-byte region [ffff8881cf7aedc0, ffff8881cf7aeea0)
The buggy address belongs to the page:
page:ffffea00073deb80 count:1 mapcount:0 mapping:          (null) index:0xffff8881cf7aec80
flags: 0x4000000000000200(slab)
raw: 4000000000000200 0000000000000000 ffff8881cf7aec80 00000001800c000b
raw: ffffea00073d0980 0000000200000002 ffff8881dab70200 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8881cf7aed00: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
 ffff8881cf7aed80: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
>ffff8881cf7aee00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                                ^
 ffff8881cf7aee80: fb fb fb fb fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8881cf7aef00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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