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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 ffff888090605448 by task ksoftirqd/0/9

CPU: 0 PID: 9 Comm: ksoftirqd/0 Not tainted 5.0.0-rc4+ #39
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+0x172/0x1f0 lib/dump_stack.c:113
 print_address_description.cold+0x7c/0x20d mm/kasan/report.c:187
 kasan_report.cold+0x1b/0x40 mm/kasan/report.c:317
 __asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:135
 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+0x928/0x1390 kernel/rcu/tree.c:2754
 __do_softirq+0x266/0x95a kernel/softirq.c:292
audit: type=1804 audit(1550364264.773:62): pid=12026 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=invalid_pcr cause=open_writers comm="syz-executor.0" name="/root/syzkaller-testdir756217463/syzkaller.C0FgaT/152/memory.events" dev="sda1" ino=16522 res=1
 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 12014:
 save_stack+0x45/0xd0 mm/kasan/common.c:73
 set_track mm/kasan/common.c:85 [inline]
 __kasan_kmalloc mm/kasan/common.c:496 [inline]
 __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:469
 kasan_kmalloc+0x9/0x10 mm/kasan/common.c:504
 kmem_cache_alloc_trace+0x151/0x760 mm/slab.c:3609
 kmalloc include/linux/slab.h:545 [inline]
 kzalloc include/linux/slab.h:740 [inline]
 dev_map_alloc kernel/bpf/devmap.c:102 [inline]
 dev_map_alloc+0x1be/0x6e0 kernel/bpf/devmap.c:88
 find_and_alloc_map kernel/bpf/syscall.c:129 [inline]
 map_create kernel/bpf/syscall.c:526 [inline]
 __do_sys_bpf+0x97b/0x3ea0 kernel/bpf/syscall.c:2642
 __se_sys_bpf kernel/bpf/syscall.c:2619 [inline]
 __x64_sys_bpf+0x73/0xb0 kernel/bpf/syscall.c:2619
 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 7582:
 save_stack+0x45/0xd0 mm/kasan/common.c:73
 set_track mm/kasan/common.c:85 [inline]
 __kasan_slab_free+0x102/0x150 mm/kasan/common.c:458
 kasan_slab_free+0xe/0x10 mm/kasan/common.c:466
 __cache_free mm/slab.c:3487 [inline]
 kfree+0xcf/0x230 mm/slab.c:3806
 dev_map_free+0x43c/0x540 kernel/bpf/devmap.c:192
 bpf_map_free_deferred+0xba/0xf0 kernel/bpf/syscall.c:290
 process_one_work+0x98e/0x1760 kernel/workqueue.c:2153
kobject: 'loop3' (0000000036b2a006): kobject_uevent_env
 worker_thread+0x98/0xe40 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 ffff888090605340
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 264 bytes inside of
 512-byte region [ffff888090605340, ffff888090605540)
The buggy address belongs to the page:
page:ffffea0002418140 count:1 mapcount:0 mapping:ffff88812c3f0940 index:0x0
flags: 0x1fffc0000000200(slab)
raw: 01fffc0000000200 ffffea00024d4688 ffffea00025cee08 ffff88812c3f0940
raw: 0000000000000000 ffff8880906050c0 0000000100000006 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff888090605300: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
 ffff888090605380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888090605400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                              ^
 ffff888090605480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888090605500: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
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