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BUG: KASAN: use-after-free in dev_map_flush_old kernel/bpf/devmap.c:389 [inline]
BUG: KASAN: use-after-free in __dev_map_entry_free+0x2a9/0x330 kernel/bpf/devmap.c:403
Read of size 8 at addr ffff88809f6cdd88 by task ksoftirqd/0/9

CPU: 0 PID: 9 Comm: ksoftirqd/0 Not tainted 4.20.0+ #3
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1db/0x2d0 lib/dump_stack.c:113
 print_address_description.cold+0x7c/0x20d mm/kasan/report.c:256
 kasan_report_error mm/kasan/report.c:354 [inline]
 kasan_report mm/kasan/report.c:412 [inline]
 kasan_report.cold+0x8c/0x2ba mm/kasan/report.c:396
 __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433
 dev_map_flush_old kernel/bpf/devmap.c:389 [inline]
 __dev_map_entry_free+0x2a9/0x330 kernel/bpf/devmap.c:403
 __rcu_reclaim kernel/rcu/rcu.h:240 [inline]
 rcu_do_batch kernel/rcu/tree.c:2452 [inline]
 invoke_rcu_callbacks kernel/rcu/tree.c:2773 [inline]
 rcu_process_callbacks+0xc4a/0x1680 kernel/rcu/tree.c:2754
 __do_softirq+0x30b/0xb11 kernel/softirq.c:292
 run_ksoftirqd kernel/softirq.c:654 [inline]
 run_ksoftirqd+0x8e/0x110 kernel/softirq.c:646
 smpboot_thread_fn+0x6ab/0xa10 kernel/smpboot.c:164
 kthread+0x357/0x430 kernel/kthread.c:246
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352

Allocated by task 30101:
 save_stack+0x45/0xd0 mm/kasan/kasan.c:448
 set_track mm/kasan/kasan.c:460 [inline]
 kasan_kmalloc mm/kasan/kasan.c:553 [inline]
 kasan_kmalloc+0xce/0xf0 mm/kasan/kasan.c:531
 kmem_cache_alloc_trace+0x152/0x760 mm/slab.c:3620
 kmalloc include/linux/slab.h:546 [inline]
 kzalloc include/linux/slab.h:741 [inline]
 dev_map_alloc kernel/bpf/devmap.c:102 [inline]
 dev_map_alloc+0x205/0x800 kernel/bpf/devmap.c:88
 find_and_alloc_map kernel/bpf/syscall.c:129 [inline]
 map_create kernel/bpf/syscall.c:510 [inline]
 __do_sys_bpf+0x6df/0x4410 kernel/bpf/syscall.c:2603
 __se_sys_bpf kernel/bpf/syscall.c:2580 [inline]
 __x64_sys_bpf+0x73/0xb0 kernel/bpf/syscall.c:2580
 do_syscall_64+0x1a3/0x800 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 2971:
 save_stack+0x45/0xd0 mm/kasan/kasan.c:448
 set_track mm/kasan/kasan.c:460 [inline]
 __kasan_slab_free+0x102/0x150 mm/kasan/kasan.c:521
 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528
 __cache_free mm/slab.c:3498 [inline]
 kfree+0xcf/0x230 mm/slab.c:3817
 dev_map_free+0x522/0x6b0 kernel/bpf/devmap.c:192
 bpf_map_free_deferred+0xba/0xf0 kernel/bpf/syscall.c:290
 process_one_work+0xd0c/0x1ce0 kernel/workqueue.c:2153
 worker_thread+0x143/0x14a0 kernel/workqueue.c:2296
 kthread+0x357/0x430 kernel/kthread.c:246
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352

The buggy address belongs to the object at ffff88809f6cdc80
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 264 bytes inside of
 512-byte region [ffff88809f6cdc80, ffff88809f6cde80)
The buggy address belongs to the page:
page:ffffea00027db340 count:1 mapcount:0 mapping:ffff88812c3f0940 index:0xffff88809f6cd780
flags: 0x1fffc0000000200(slab)
raw: 01fffc0000000200 ffffea0001750708 ffffea00023d0688 ffff88812c3f0940
raw: ffff88809f6cd780 ffff88809f6cd000 0000000100000005 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88809f6cdc80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88809f6cdd00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88809f6cdd80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                      ^
 ffff88809f6cde00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88809f6cde80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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