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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 1 at addr ffff8801d472de00 by task syz-executor0/3698

CPU: 0 PID: 3698 Comm: syz-executor0 Not tainted 4.15.0-rc7+ #187
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:1808 [inline]
 SyS_bpf+0x922/0x4400 kernel/bpf/syscall.c:1782
 entry_SYSCALL_64_fastpath+0x23/0x9a
RIP: 0033:0x452cf9
RSP: 002b:00007f83e4267c58 EFLAGS: 00000212 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 000000000071bea0 RCX: 0000000000452cf9
RDX: 0000000000000018 RSI: 0000000020eab000 RDI: 0000000000000001
RBP: 0000000000000037 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000212 R12: 00000000006ee5c8
R13: 00000000ffffffff R14: 00007f83e42686d4 R15: 0000000000000000

Allocated by task 31723:
 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
 kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:489
 kmem_cache_alloc+0x12e/0x760 mm/slab.c:3544
 getname_flags+0xcb/0x580 fs/namei.c:138
 user_path_at_empty+0x2d/0x50 fs/namei.c:2590
 user_path_at include/linux/namei.h:57 [inline]
 SYSC_faccessat fs/open.c:384 [inline]
 SyS_faccessat fs/open.c:353 [inline]
 SYSC_access fs/open.c:431 [inline]
 SyS_access+0x22c/0x6a0 fs/open.c:429
 entry_SYSCALL_64_fastpath+0x23/0x9a

Freed by task 31723:
 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]
 kmem_cache_free+0x83/0x2a0 mm/slab.c:3746
 putname+0xee/0x130 fs/namei.c:258
 filename_lookup+0x315/0x500 fs/namei.c:2345
 user_path_at_empty+0x40/0x50 fs/namei.c:2590
 user_path_at include/linux/namei.h:57 [inline]
 SYSC_faccessat fs/open.c:384 [inline]
 SyS_faccessat fs/open.c:353 [inline]
 SYSC_access fs/open.c:431 [inline]
 SyS_access+0x22c/0x6a0 fs/open.c:429
 entry_SYSCALL_64_fastpath+0x23/0x9a

The buggy address belongs to the object at ffff8801d472c4c0
 which belongs to the cache names_cache of size 4096
The buggy address is located 2368 bytes to the right of
 4096-byte region [ffff8801d472c4c0, ffff8801d472d4c0)
The buggy address belongs to the page:
page:ffffea000751cb00 count:1 mapcount:0 mapping:ffff8801d472c4c0 index:0x0 compound_mapcount: 0
flags: 0x2fffc0000008100(slab|head)
raw: 02fffc0000008100 ffff8801d472c4c0 0000000000000000 0000000100000001
raw: ffffea00071ce0a0 ffffea000751ab20 ffff8801dae2c600 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801d472dd00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8801d472dd80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff8801d472de00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                   ^
 ffff8801d472de80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8801d472df00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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