netlink: 32 bytes leftover after parsing attributes in process `syz-executor.5'.
==================================================================
BUG: KASAN: slab-out-of-bounds in skb_at_tc_ingress include/net/sch_generic.h:452 [inline]
BUG: KASAN: slab-out-of-bounds in bpf_push_mac_rcsum net/core/filter.c:1422 [inline]
BUG: KASAN: slab-out-of-bounds in ____bpf_skb_vlan_push net/core/filter.c:1970 [inline]
BUG: KASAN: slab-out-of-bounds in bpf_skb_vlan_push+0x471/0x540 net/core/filter.c:1961
Read of size 4 at addr ffff8881a6303108 by task syz-executor.3/3189

CPU: 1 PID: 3189 Comm: syz-executor.3 Not tainted 4.14.148+ #0
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0xca/0x134 lib/dump_stack.c:53
 print_address_description+0x60/0x226 mm/kasan/report.c:187
 __kasan_report.cold+0x1a/0x41 mm/kasan/report.c:316
 skb_at_tc_ingress include/net/sch_generic.h:452 [inline]
 bpf_push_mac_rcsum net/core/filter.c:1422 [inline]
 ____bpf_skb_vlan_push net/core/filter.c:1970 [inline]
 bpf_skb_vlan_push+0x471/0x540 net/core/filter.c:1961
 ___bpf_prog_run+0x2478/0x5510 kernel/bpf/core.c:1095

Allocated by task 190:
 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
 kobject_synth_uevent+0x5d9/0x6ef lib/kobject_uevent.c:205
 uevent_store+0x21/0x60 drivers/base/core.c:996
 dev_attr_store+0x59/0x80 drivers/base/core.c:714
 sysfs_kf_write+0x109/0x160 fs/sysfs/file.c:141
 kernfs_fop_write+0x28b/0x440 fs/kernfs/file.c:316
 __vfs_write+0xf9/0x5a0 fs/read_write.c:482
 vfs_write+0x17f/0x4d0 fs/read_write.c:546
 SYSC_write fs/read_write.c:594 [inline]
 SyS_write+0x102/0x250 fs/read_write.c:586
 do_syscall_64+0x19b/0x520 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
 0xffffffffffffffff

Freed by task 190:
 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
 kobject_synth_uevent+0x5d9/0x6ef lib/kobject_uevent.c:205
 uevent_store+0x21/0x60 drivers/base/core.c:996
 dev_attr_store+0x59/0x80 drivers/base/core.c:714
 sysfs_kf_write+0x109/0x160 fs/sysfs/file.c:141
 kernfs_fop_write+0x28b/0x440 fs/kernfs/file.c:316
 __vfs_write+0xf9/0x5a0 fs/read_write.c:482
 vfs_write+0x17f/0x4d0 fs/read_write.c:546
 SYSC_write fs/read_write.c:594 [inline]
 SyS_write+0x102/0x250 fs/read_write.c:586
 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 ffff8881a6303000
 which belongs to the cache skbuff_head_cache of size 224
The buggy address is located 40 bytes to the right of
 224-byte region [ffff8881a6303000, ffff8881a63030e0)
The buggy address belongs to the page:
page:ffffea000698c0c0 count:1 mapcount:0 mapping:          (null) index:0x0
flags: 0x4000000000000200(slab)
raw: 4000000000000200 0000000000000000 0000000000000000 00000001800c000c
raw: 0000000000000000 0000000100000001 ffff8881dab70200 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8881a6303000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8881a6303080: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
>ffff8881a6303100: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
                      ^
 ffff8881a6303180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8881a6303200: fb fb fb fb fc fc fc fc fc fc fc fc fc fc fc fc
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