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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 ffff8801d21b0ea0 by task syz-executor3/9212

CPU: 0 PID: 9212 Comm: syz-executor3 Not tainted 4.15.0-rc7+ #189
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:1808 [inline]
 SyS_bpf+0x922/0x4400 kernel/bpf/syscall.c:1782
 entry_SYSCALL_64_fastpath+0x23/0x9a
RIP: 0033:0x452cf9
RSP: 002b:00007f463b1bdc58 EFLAGS: 00000212 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 000000000071bea0 RCX: 0000000000452cf9
RDX: 0000000000000018 RSI: 0000000020feffe8 RDI: 0000000000000001
RBP: 0000000000000037 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000212 R12: 00000000006ee5c8
R13: 00000000ffffffff R14: 00007f463b1be6d4 R15: 0000000000000000

Allocated by task 2446:
 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
 prepare_creds+0x78/0x360 kernel/cred.c:252
 SYSC_faccessat fs/open.c:365 [inline]
 SyS_faccessat fs/open.c:353 [inline]
 SYSC_access fs/open.c:431 [inline]
 SyS_access+0x8f/0x6a0 fs/open.c:429
 entry_SYSCALL_64_fastpath+0x23/0x9a

Freed by task 2447:
 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
 put_cred_rcu+0x263/0x400 kernel/cred.c:126
 __rcu_reclaim kernel/rcu/rcu.h:195 [inline]
 rcu_do_batch kernel/rcu/tree.c:2758 [inline]
 invoke_rcu_callbacks kernel/rcu/tree.c:3012 [inline]
 __rcu_process_callbacks kernel/rcu/tree.c:2979 [inline]
 rcu_process_callbacks+0xd6c/0x17f0 kernel/rcu/tree.c:2996
 __do_softirq+0x2d7/0xb85 kernel/softirq.c:285

The buggy address belongs to the object at ffff8801d21b0e00
 which belongs to the cache cred_jar of size 168
The buggy address is located 160 bytes inside of
 168-byte region [ffff8801d21b0e00, ffff8801d21b0ea8)
The buggy address belongs to the page:
page:ffffea0007486c00 count:1 mapcount:0 mapping:ffff8801d21b0000 index:0xffff8801d21b0e00
flags: 0x2fffc0000000100(slab)
raw: 02fffc0000000100 ffff8801d21b0000 ffff8801d21b0e00 0000000100000009
raw: ffffea0007635760 ffffea0007485fe0 ffff8801dad30380 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801d21b0d80: fb fb fb fb fb fc fc fc fc fc fc fc fc fc fc fc
 ffff8801d21b0e00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8801d21b0e80: fb fb fb fb fb fc fc fc fc fc fc fc fc fc fc fc
                               ^
 ffff8801d21b0f00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8801d21b0f80: fb fb fb fb fb fc fc fc fc fc fc fc fc fc fc fc
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