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BUG: KASAN: slab-out-of-bounds in _copy_to_user+0x9a/0xc0 lib/usercopy.c:27
Read of size 660 at addr ffff88019f57fffa by task syz-executor2/4667

CPU: 0 PID: 4667 Comm: syz-executor2 Not tainted 4.14.76+ #20
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0xb9/0x11b lib/dump_stack.c:53
 print_address_description+0x60/0x22b mm/kasan/report.c:252
 kasan_report_error mm/kasan/report.c:351 [inline]
 kasan_report.cold.6+0x11b/0x2dd mm/kasan/report.c:409
 _copy_to_user+0x9a/0xc0 lib/usercopy.c:27
 copy_to_user include/linux/uaccess.h:155 [inline]
 bpf_test_finish.isra.0+0xc8/0x190 net/bpf/test_run.c:59
 bpf_prog_test_run_skb+0x4d0/0x8c0 net/bpf/test_run.c:144
 bpf_prog_test_run kernel/bpf/syscall.c:1330 [inline]
 SYSC_bpf kernel/bpf/syscall.c:1602 [inline]
 SyS_bpf+0x79d/0x3640 kernel/bpf/syscall.c:1547
 do_syscall_64+0x19b/0x4b0 arch/x86/entry/common.c:289
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x457569
RSP: 002b:00007f0ca4424c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000457569
RDX: 0000000000000028 RSI: 0000000020000000 RDI: 000000000000000a
RBP: 000000000072bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f0ca44256d4
R13: 00000000004bd892 R14: 00000000004cc208 R15: 00000000ffffffff

Allocated by task 4543:
 save_stack mm/kasan/kasan.c:447 [inline]
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_kmalloc.part.1+0x4f/0xd0 mm/kasan/kasan.c:551
 slab_post_alloc_hook mm/slab.h:442 [inline]
 slab_alloc_node mm/slub.c:2723 [inline]
 slab_alloc mm/slub.c:2731 [inline]
 kmem_cache_alloc+0xe4/0x2b0 mm/slub.c:2736
 getname_flags+0xc4/0x540 fs/namei.c:138
 user_path_at_empty+0x28/0x80 fs/namei.c:2611
 user_path_at include/linux/namei.h:57 [inline]
 SYSC_faccessat fs/open.c:394 [inline]
 SyS_faccessat+0x20d/0x660 fs/open.c:362
 do_syscall_64+0x19b/0x4b0 arch/x86/entry/common.c:289
 entry_SYSCALL_64_after_hwframe+0x42/0xb7

Freed by task 4543:
 save_stack mm/kasan/kasan.c:447 [inline]
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_slab_free+0xac/0x190 mm/kasan/kasan.c:524
 slab_free_hook mm/slub.c:1389 [inline]
 slab_free_freelist_hook mm/slub.c:1410 [inline]
 slab_free mm/slub.c:2966 [inline]
 kmem_cache_free+0x12d/0x350 mm/slub.c:2988
 putname+0xcf/0x100 fs/namei.c:259
 filename_lookup.part.18+0x21e/0x370 fs/namei.c:2359
 filename_lookup fs/namei.c:2343 [inline]
 user_path_at_empty+0x4b/0x80 fs/namei.c:2611
 user_path_at include/linux/namei.h:57 [inline]
 SYSC_faccessat fs/open.c:394 [inline]
 SyS_faccessat+0x20d/0x660 fs/open.c:362
 do_syscall_64+0x19b/0x4b0 arch/x86/entry/common.c:289
 entry_SYSCALL_64_after_hwframe+0x42/0xb7

The buggy address belongs to the object at ffff88019f57e600
 which belongs to the cache names_cache of size 4096
The buggy address is located 2554 bytes to the right of
 4096-byte region [ffff88019f57e600, ffff88019f57f600)
The buggy address belongs to the page:
page:ffffea00067d5e00 count:1 mapcount:0 mapping:          (null) index:0x0 compound_mapcount: 0
flags: 0x4000000000008100(slab|head)
raw: 4000000000008100 0000000000000000 0000000000000000 0000000100070007
raw: dead000000000100 dead000000000200 ffff8801da97e000 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88019f57fe80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88019f57ff00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88019f57ff80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                                                                ^
 ffff88019f580000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88019f580080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
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