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BUG: KASAN: slab-out-of-bounds in memcpy include/linux/string.h:344 [inline]
BUG: KASAN: slab-out-of-bounds in map_lookup_elem+0x4dc/0xbd0 kernel/bpf/syscall.c:584
Read of size 3 at addr ffff8801d6c53278 by task syz-executor6/17421

CPU: 1 PID: 17421 Comm: syz-executor6 Not tainted 4.15.0-rc7+ #262
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x194/0x257 lib/dump_stack.c:53
 print_address_description+0x73/0x250 mm/kasan/report.c:252
 kasan_report_error mm/kasan/report.c:351 [inline]
 kasan_report+0x25b/0x340 mm/kasan/report.c:409
 check_memory_region_inline mm/kasan/kasan.c:260 [inline]
 check_memory_region+0x137/0x190 mm/kasan/kasan.c:267
 memcpy+0x23/0x50 mm/kasan/kasan.c:302
 memcpy include/linux/string.h:344 [inline]
 map_lookup_elem+0x4dc/0xbd0 kernel/bpf/syscall.c:584
 SYSC_bpf kernel/bpf/syscall.c:1711 [inline]
 SyS_bpf+0x922/0x4400 kernel/bpf/syscall.c:1685
 entry_SYSCALL_64_fastpath+0x29/0xa0
RIP: 0033:0x452cf9
RSP: 002b:00007fae0801bc58 EFLAGS: 00000212 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 000000000071bea0 RCX: 0000000000452cf9
RDX: 0000000000000018 RSI: 00000000206d1fe8 RDI: 0000000000000001
RBP: 0000000000000037 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000212 R12: 00000000006ee5c8
R13: 00000000ffffffff R14: 00007fae0801c6d4 R15: 0000000000000000

Allocated by task 16820:
 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 mm/slab.c:3708 [inline]
 __kmalloc+0x162/0x760 mm/slab.c:3717
 kmalloc include/linux/slab.h:504 [inline]
 kzalloc include/linux/slab.h:688 [inline]
 __proc_create+0x21a/0x880 fs/proc/generic.c:366
 proc_create_data+0x76/0x180 fs/proc/generic.c:488
 proc_create+0x2f/0x40 fs/proc/generic.c:508
 raw_init_net+0x4a/0x70 net/ipv4/raw.c:1131
 ops_init+0x10a/0x570 net/core/net_namespace.c:118
 setup_net+0x313/0x710 net/core/net_namespace.c:295
 copy_net_ns+0x27c/0x580 net/core/net_namespace.c:419
 create_new_namespaces+0x425/0x880 kernel/nsproxy.c:107
 unshare_nsproxy_namespaces+0xae/0x1e0 kernel/nsproxy.c:206
 SYSC_unshare kernel/fork.c:2365 [inline]
 SyS_unshare+0x653/0xfa0 kernel/fork.c:2315
 entry_SYSCALL_64_fastpath+0x29/0xa0

Freed by task 6688:
 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:3488 [inline]
 kfree+0xd6/0x260 mm/slab.c:3803
 free_proc_entry fs/proc/generic.c:531 [inline]
 pde_put+0x9a/0xf0 fs/proc/generic.c:537
 remove_proc_entry+0x1e3/0x360 fs/proc/generic.c:573
 ip6mr_net_exit+0x40/0x90 net/ipv6/ip6mr.c:1392
 ops_exit_list.isra.6+0xae/0x150 net/core/net_namespace.c:142
 cleanup_net+0x5c7/0xb50 net/core/net_namespace.c:484
 process_one_work+0xbbf/0x1b10 kernel/workqueue.c:2112
 worker_thread+0x223/0x1990 kernel/workqueue.c:2246
 kthread+0x33c/0x400 kernel/kthread.c:238
 ret_from_fork+0x37/0x50 arch/x86/entry/entry_64.S:530

The buggy address belongs to the object at ffff8801d6c53180
 which belongs to the cache kmalloc-256 of size 256
The buggy address is located 248 bytes inside of
 256-byte region [ffff8801d6c53180, ffff8801d6c53280)
The buggy address belongs to the page:
page:ffffea00075b14c0 count:1 mapcount:0 mapping:ffff8801d6c53040 index:0x0
flags: 0x2fffc0000000100(slab)
raw: 02fffc0000000100 ffff8801d6c53040 0000000000000000 000000010000000c
raw: ffffea0007411960 ffffea00074b0ce0 ffff8801dac007c0 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801d6c53100: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc
 ffff8801d6c53180: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8801d6c53200: 00 00 00 00 00 00 00 00 00 04 fc fc fc fc fc fc
                                                                ^
 ffff8801d6c53280: fc fc fc fc fc fc fc fc 00 00 00 00 00 00 00 00
 ffff8801d6c53300: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
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