==================================================================
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 ffff8801d276f778 by task syz-executor4/4121

CPU: 0 PID: 4121 Comm: syz-executor4 Not tainted 4.15.0-rc7+ #259
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+0x23/0x9a
RIP: 0033:0x452ac9
RSP: 002b:00007fd757cddc58 EFLAGS: 00000212 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 000000000071bea0 RCX: 0000000000452ac9
RDX: 0000000000000018 RSI: 00000000206d1fe8 RDI: 0000000000000001
RBP: 0000000000000036 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000212 R12: 00000000006ee5b0
R13: 00000000ffffffff R14: 00007fd757cde6d4 R15: 0000000000000000

Allocated by task 2600:
 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
 kmem_cache_alloc_trace+0x136/0x750 mm/slab.c:3610
 kmalloc include/linux/slab.h:499 [inline]
 kzalloc include/linux/slab.h:688 [inline]
 do_execveat_common.isra.30+0x3ea/0x23c0 fs/exec.c:1729
 do_execve fs/exec.c:1847 [inline]
 SYSC_execve fs/exec.c:1928 [inline]
 SyS_execve+0x39/0x50 fs/exec.c:1923
 do_syscall_64+0x273/0x920 arch/x86/entry/common.c:285
 return_from_SYSCALL_64+0x0/0x75

Freed by task 2600:
 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_bprm+0x19d/0x200 fs/exec.c:1414
 do_execveat_common.isra.30+0x1a24/0x23c0 fs/exec.c:1812
 do_execve fs/exec.c:1847 [inline]
 SYSC_execve fs/exec.c:1928 [inline]
 SyS_execve+0x39/0x50 fs/exec.c:1923
 do_syscall_64+0x273/0x920 arch/x86/entry/common.c:285
 return_from_SYSCALL_64+0x0/0x75

The buggy address belongs to the object at ffff8801d276f680
 which belongs to the cache kmalloc-256 of size 256
The buggy address is located 248 bytes inside of
 256-byte region [ffff8801d276f680, ffff8801d276f780)
The buggy address belongs to the page:
page:ffffea000749dbc0 count:1 mapcount:0 mapping:ffff8801d276f040 index:0x0
flags: 0x2fffc0000000100(slab)
raw: 02fffc0000000100 ffff8801d276f040 0000000000000000 000000010000000c
raw: ffffea000748a460 ffffea0007460aa0 ffff8801dac007c0 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801d276f600: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc
 ffff8801d276f680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8801d276f700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                                ^
 ffff8801d276f780: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
 ffff8801d276f800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================