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BUG: KASAN: use-after-free in __read_once_size include/linux/compiler.h:183 [inline]
BUG: KASAN: use-after-free in bpf_fd_array_map_lookup_elem+0x440/0x4c0 kernel/bpf/arraymap.c:374
Read of size 8 at addr ffff8801c9730ef8 by task syz-executor4/22686

CPU: 1 PID: 22686 Comm: syz-executor4 Not tainted 4.15.0-rc8+ #263
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
 __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:430
 __read_once_size include/linux/compiler.h:183 [inline]
 bpf_fd_array_map_lookup_elem+0x440/0x4c0 kernel/bpf/arraymap.c:374
 map_lookup_elem+0x6b5/0xbd0 kernel/bpf/syscall.c:577
 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:00007febdccc0c58 EFLAGS: 00000212 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 000000000071bea0 RCX: 0000000000452cf9
RDX: 0000000000000018 RSI: 00000000206d1fe8 RDI: 0000000000000001
RBP: 00000000000003ad R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000212 R12: 00000000006f38d8
R13: 00000000ffffffff R14: 00007febdccc16d4 R15: 0000000000000000

Allocated by task 19294:
 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_node mm/slab.c:3672 [inline]
 __kmalloc_node+0x47/0x70 mm/slab.c:3679
 kmalloc_node include/linux/slab.h:541 [inline]
 kvmalloc_node+0x99/0xd0 mm/util.c:397
 kvmalloc include/linux/mm.h:541 [inline]
 SYSC_add_key security/keys/keyctl.c:104 [inline]
 SyS_add_key+0x2ad/0x380 security/keys/keyctl.c:62
 entry_SYSCALL_64_fastpath+0x29/0xa0

Freed by task 19294:
 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
 kvfree+0x36/0x60 mm/util.c:416
 SYSC_add_key security/keys/keyctl.c:137 [inline]
 SyS_add_key+0x311/0x380 security/keys/keyctl.c:62
 entry_SYSCALL_64_fastpath+0x29/0xa0

The buggy address belongs to the object at ffff8801c9730e00
 which belongs to the cache kmalloc-256 of size 256
The buggy address is located 248 bytes inside of
 256-byte region [ffff8801c9730e00, ffff8801c9730f00)
The buggy address belongs to the page:
page:ffffea000725cc00 count:1 mapcount:0 mapping:ffff8801c9730040 index:0xffff8801c9730680
flags: 0x2fffc0000000100(slab)
raw: 02fffc0000000100 ffff8801c9730040 ffff8801c9730680 000000010000000b
raw: ffffea0006f4ce60 ffffea0006f6a8e0 ffff8801dac007c0 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801c9730d80: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc
 ffff8801c9730e00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8801c9730e80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                                ^
 ffff8801c9730f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8801c9730f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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