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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+0x2ab/0x300 kernel/bpf/devmap.c:403
Read of size 8 at addr ffff8881c4b2a8c8 by task ksoftirqd/1/16

CPU: 1 PID: 16 Comm: ksoftirqd/1 Not tainted 4.20.0-rc2+ #333
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+0x244/0x39d lib/dump_stack.c:113
 print_address_description.cold.7+0x9/0x1ff mm/kasan/report.c:256
 kasan_report_error mm/kasan/report.c:354 [inline]
 kasan_report.cold.8+0x242/0x309 mm/kasan/report.c:412
 __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+0x2ab/0x300 kernel/bpf/devmap.c:403
 __rcu_reclaim kernel/rcu/rcu.h:240 [inline]
 rcu_do_batch kernel/rcu/tree.c:2437 [inline]
 invoke_rcu_callbacks kernel/rcu/tree.c:2716 [inline]
 rcu_process_callbacks+0x100a/0x1ac0 kernel/rcu/tree.c:2697
 __do_softirq+0x308/0xb7e kernel/softirq.c:292
 run_ksoftirqd+0x5e/0x100 kernel/softirq.c:654
 smpboot_thread_fn+0x68b/0xa00 kernel/smpboot.c:164
 kthread+0x35a/0x440 kernel/kthread.c:246
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352

Allocated by task 9245:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:448
 set_track mm/kasan/kasan.c:460 [inline]
 kasan_kmalloc+0xc7/0xe0 mm/kasan/kasan.c:553
 kmem_cache_alloc_trace+0x152/0x750 mm/slab.c:3620
 kmalloc include/linux/slab.h:546 [inline]
 kzalloc include/linux/slab.h:741 [inline]
 dev_map_alloc+0x210/0x800 kernel/bpf/devmap.c:102
 find_and_alloc_map kernel/bpf/syscall.c:129 [inline]
 map_create+0x3bd/0x1110 kernel/bpf/syscall.c:509
 __do_sys_bpf kernel/bpf/syscall.c:2489 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:2466 [inline]
 __x64_sys_bpf+0x303/0x520 kernel/bpf/syscall.c:2466
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 22:
 save_stack+0x43/0xd0 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+0x514/0x690 kernel/bpf/devmap.c:192
 bpf_map_free_deferred+0xd9/0x110 kernel/bpf/syscall.c:290
 process_one_work+0xc90/0x1c40 kernel/workqueue.c:2153
 worker_thread+0x17f/0x1390 kernel/workqueue.c:2296
 kthread+0x35a/0x440 kernel/kthread.c:246
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352

The buggy address belongs to the object at ffff8881c4b2a7c0
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 264 bytes inside of
 512-byte region [ffff8881c4b2a7c0, ffff8881c4b2a9c0)
The buggy address belongs to the page:
page:ffffea000712ca80 count:1 mapcount:0 mapping:ffff8881da800940 index:0xffff8881c4b2a540
flags: 0x2fffc0000000200(slab)
raw: 02fffc0000000200 ffffea0006d73f48 ffffea0007190bc8 ffff8881da800940
raw: ffff8881c4b2a540 ffff8881c4b2a040 0000000100000003 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8881c4b2a780: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
 ffff8881c4b2a800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8881c4b2a880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                              ^
 ffff8881c4b2a900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8881c4b2a980: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
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