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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 ffff8801bfca82f8 by task syz-executor4/30638

CPU: 0 PID: 30638 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: 0033:0x452df9
RSP: 002b:00007f194f56ac58 EFLAGS: 00000212 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 000000000071bea0 RCX: 0000000000452df9
RDX: 0000000000000018 RSI: 00000000206d1fe8 RDI: 0000000000000001
RBP: 0000000000000038 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000212 R12: 00000000006ee5e0
R13: 00000000ffffffff R14: 00007f194f56b6d4 R15: 0000000000000000

Allocated by task 30484:
 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]
 bpf_map_area_alloc+0x32/0x80 kernel/bpf/syscall.c:123
 prealloc_init kernel/bpf/hashtab.c:146 [inline]
 htab_map_alloc+0xb66/0x1200 kernel/bpf/hashtab.c:368
 find_and_alloc_map kernel/bpf/syscall.c:105 [inline]
 map_create kernel/bpf/syscall.c:404 [inline]
 SYSC_bpf kernel/bpf/syscall.c:1708 [inline]
 SyS_bpf+0x7f8/0x4400 kernel/bpf/syscall.c:1685
 entry_SYSCALL_64_fastpath+0x29/0xa0

Freed by task 17002:
 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
 bpf_map_area_free+0x15/0x20 kernel/bpf/syscall.c:134
 htab_free_elems+0x88/0x270 kernel/bpf/hashtab.c:120
 prealloc_destroy+0x17/0x90 kernel/bpf/hashtab.c:198
 htab_map_free+0xe6/0x640 kernel/bpf/hashtab.c:1138
 bpf_map_free_deferred+0xb0/0xe0 kernel/bpf/syscall.c:217
 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 ffff8801bfca8200
 which belongs to the cache kmalloc-256 of size 256
The buggy address is located 248 bytes inside of
 256-byte region [ffff8801bfca8200, ffff8801bfca8300)
The buggy address belongs to the page:
page:ffffea0006ff2a00 count:1 mapcount:0 mapping:ffff8801bfca80c0 index:0xffff8801bfca8480
flags: 0x2fffc0000000100(slab)
raw: 02fffc0000000100 ffff8801bfca80c0 ffff8801bfca8480 000000010000000a
raw: ffffea000720f6a0 ffffea00076b57e0 ffff8801dac007c0 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801bfca8180: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc
 ffff8801bfca8200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8801bfca8280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                                ^
 ffff8801bfca8300: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
 ffff8801bfca8380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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