==================================================================
BUG: KASAN: slab-out-of-bounds in _copy_to_user+0x9d/0xd0 lib/usercopy.c:27
Read of size 1809 at addr ffff88819cff7ffd by task syz-executor.1/25271

CPU: 1 PID: 25271 Comm: syz-executor.1 Not tainted 4.14.139+ #34
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0xca/0x134 lib/dump_stack.c:53
TCP: request_sock_TCPv6: Possible SYN flooding on port 20002. Dropping request.  Check SNMP counters.
 print_address_description+0x60/0x226 mm/kasan/report.c:187
 __kasan_report.cold+0x1a/0x41 mm/kasan/report.c:316
 _copy_to_user+0x9d/0xd0 lib/usercopy.c:27
 copy_to_user include/linux/uaccess.h:155 [inline]
 bpf_test_finish.isra.0+0xa7/0x160 net/bpf/test_run.c:59
 bpf_prog_test_run_skb+0x528/0x8c0 net/bpf/test_run.c:144
 bpf_prog_test_run kernel/bpf/syscall.c:1346 [inline]
 SYSC_bpf kernel/bpf/syscall.c:1618 [inline]
 SyS_bpf+0xa3b/0x3830 kernel/bpf/syscall.c:1563
 do_syscall_64+0x19b/0x520 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x459829
RSP: 002b:00007f0709fbdc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000459829
RDX: 0000000000000028 RSI: 00000000200002c0 RDI: 000000000000000a
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f0709fbe6d4
R13: 00000000004bfb92 R14: 00000000004d1818 R15: 00000000ffffffff

Allocated by task 25146:
 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:495
 slab_post_alloc_hook mm/slab.h:439 [inline]
 slab_alloc_node mm/slub.c:2758 [inline]
 slab_alloc mm/slub.c:2766 [inline]
 kmem_cache_alloc+0xd2/0x2e0 mm/slub.c:2771
 kmem_cache_alloc_node include/linux/slab.h:361 [inline]
 alloc_task_struct_node kernel/fork.c:159 [inline]
 dup_task_struct kernel/fork.c:525 [inline]
 copy_process.part.0+0x14f4/0x66c0 kernel/fork.c:1729
 copy_process kernel/fork.c:1679 [inline]
 _do_fork+0x197/0xce0 kernel/fork.c:2220
 do_syscall_64+0x19b/0x520 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
 0xffffffffffffffff

Freed by task 7:
 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:457
 slab_free_hook mm/slub.c:1403 [inline]
 slab_free_freelist_hook mm/slub.c:1430 [inline]
 slab_free mm/slub.c:3005 [inline]
 kmem_cache_free+0xcb/0x340 mm/slub.c:3021
 __put_task_struct+0x295/0x490 kernel/fork.c:430
 put_task_struct include/linux/sched/task.h:96 [inline]
 delayed_put_task_struct+0xb4/0x310 kernel/exit.c:180
 __rcu_reclaim kernel/rcu/rcu.h:195 [inline]
 rcu_do_batch kernel/rcu/tree.c:2699 [inline]
 invoke_rcu_callbacks kernel/rcu/tree.c:2962 [inline]
 __rcu_process_callbacks kernel/rcu/tree.c:2929 [inline]
 rcu_process_callbacks+0x59f/0xf60 kernel/rcu/tree.c:2946
 __do_softirq+0x234/0x9ec kernel/softirq.c:288

The buggy address belongs to the object at ffff88819cff5e00
 which belongs to the cache task_struct of size 5760
The buggy address is located 2941 bytes to the right of
 5760-byte region [ffff88819cff5e00, ffff88819cff7480)
The buggy address belongs to the page:
page:ffffea000673fc00 count:1 mapcount:0 mapping:          (null) index:0x0 compound_mapcount: 0
flags: 0x4000000000010200(slab|head)
raw: 4000000000010200 0000000000000000 0000000000000000 0000000100050005
raw: 0000000000000000 0000000200000001 ffff8881da823e00 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88819cff7e80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88819cff7f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88819cff7f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                                                                ^
 ffff88819cff8000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88819cff8080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================