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BUG: KASAN: use-after-free in __lock_acquire+0x3fa6/0x4c50 kernel/locking/lockdep.c:4225
Read of size 8 at addr ffff88808a9d6210 by task kworker/1:4/2752

CPU: 1 PID: 2752 Comm: kworker/1:4 Not tainted 5.7.0-rc1-next-20200415-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events __blk_release_queue
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x188/0x20d lib/dump_stack.c:118
 print_address_description.constprop.0.cold+0xd3/0x315 mm/kasan/report.c:382
 __kasan_report.cold+0x35/0x4d mm/kasan/report.c:511
 kasan_report+0x33/0x50 mm/kasan/common.c:625
 __lock_acquire+0x3fa6/0x4c50 kernel/locking/lockdep.c:4225
 lock_acquire+0x1f2/0x8f0 kernel/locking/lockdep.c:4934
 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
 _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:151
 lockref_get+0x11/0x50 include/linux/spinlock.h:353
 dget include/linux/dcache.h:321 [inline]
 simple_recursive_removal+0x43/0x730 fs/libfs.c:268
 debugfs_remove fs/debugfs/inode.c:703 [inline]
 debugfs_remove+0x59/0x80 fs/debugfs/inode.c:697
 blk_trace_free+0x31/0x130 kernel/trace/blktrace.c:311
 blk_trace_cleanup kernel/trace/blktrace.c:339 [inline]
 __blk_trace_remove+0x76/0xa0 kernel/trace/blktrace.c:352
 blk_trace_shutdown+0x92/0x100 kernel/trace/blktrace.c:749
 __blk_release_queue+0x212/0x380 block/blk-sysfs.c:896
 process_one_work+0x965/0x16a0 kernel/workqueue.c:2268
 worker_thread+0x96/0xe20 kernel/workqueue.c:2414
 kthread+0x388/0x470 kernel/kthread.c:268
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352

Allocated by task 15922:
 save_stack+0x1b/0x40 mm/kasan/common.c:49
 set_track mm/kasan/common.c:57 [inline]
 __kasan_kmalloc mm/kasan/common.c:495 [inline]
 __kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:468
 slab_post_alloc_hook mm/slab.h:586 [inline]
 slab_alloc mm/slab.c:3320 [inline]
 kmem_cache_alloc+0x11b/0x740 mm/slab.c:3484
 __d_alloc+0x2b/0x8e0 fs/dcache.c:1690
 d_alloc+0x4a/0x240 fs/dcache.c:1769
 d_alloc_parallel+0xe8/0x1b10 fs/dcache.c:2521
 __lookup_slow+0x193/0x490 fs/namei.c:1515
 lookup_one_len+0x163/0x190 fs/namei.c:2548
 start_creating+0x12b/0x250 fs/debugfs/inode.c:338
 __debugfs_create_file+0x62/0x400 fs/debugfs/inode.c:383
 do_blk_trace_setup+0x351/0xb30 kernel/trace/blktrace.c:524
 __blk_trace_setup+0xca/0x180 kernel/trace/blktrace.c:571
 blk_trace_ioctl+0x162/0x2b0 kernel/trace/blktrace.c:712
 blkdev_ioctl+0xbe/0x660 block/ioctl.c:711
 block_ioctl+0xf9/0x140 fs/block_dev.c:1996
 vfs_ioctl fs/ioctl.c:47 [inline]
 ksys_ioctl+0x11a/0x180 fs/ioctl.c:763
 __do_sys_ioctl fs/ioctl.c:772 [inline]
 __se_sys_ioctl fs/ioctl.c:770 [inline]
 __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:770
 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x49/0xb3

Freed by task 15924:
 save_stack+0x1b/0x40 mm/kasan/common.c:49
 set_track mm/kasan/common.c:57 [inline]
 kasan_set_free_info mm/kasan/common.c:317 [inline]
 __kasan_slab_free+0xf7/0x140 mm/kasan/common.c:456
 __cache_free mm/slab.c:3426 [inline]
 kmem_cache_free+0x7f/0x320 mm/slab.c:3694
 rcu_do_batch kernel/rcu/tree.c:2206 [inline]
 rcu_core+0x59f/0x1370 kernel/rcu/tree.c:2433
 __do_softirq+0x26c/0x9f7 kernel/softirq.c:292

The buggy address belongs to the object at ffff88808a9d6170
 which belongs to the cache dentry of size 304
The buggy address is located 160 bytes inside of
 304-byte region [ffff88808a9d6170, ffff88808a9d62a0)
The buggy address belongs to the page:
page:ffffea00022a7580 refcount:1 mapcount:0 mapping:00000000ec4d41ba index:0x0
flags: 0xfffe0000000200(slab)
raw: 00fffe0000000200 ffffea0002190e88 ffffea00022fdc48 ffff88821bc50540
raw: 0000000000000000 ffff88808a9d6000 000000010000000b 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88808a9d6100: 00 00 00 00 00 00 fc fc fc fc fc fc fc fc fb fb
 ffff88808a9d6180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88808a9d6200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                         ^
 ffff88808a9d6280: fb fb fb fb fc fc fc fc fc fc fc fc 00 00 00 00
 ffff88808a9d6300: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
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