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BUG: KASAN: use-after-free in debugfs_remove+0x10d/0x130 fs/debugfs/inode.c:684
Read of size 8 at addr ffff88808839f880 by task kworker/0:3/14876

CPU: 0 PID: 14876 Comm: kworker/0:3 Not tainted 5.2.0-rc2+ #8
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+0x172/0x1f0 lib/dump_stack.c:113
 print_address_description.cold+0x7c/0x20d mm/kasan/report.c:188
 __kasan_report.cold+0x1b/0x40 mm/kasan/report.c:317
 kasan_report+0x12/0x20 mm/kasan/common.c:614
 __asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:132
 debugfs_remove+0x10d/0x130 fs/debugfs/inode.c:684
 blk_trace_free+0x38/0x140 kernel/trace/blktrace.c:312
 blk_trace_cleanup kernel/trace/blktrace.c:339 [inline]
 __blk_trace_remove+0x78/0xa0 kernel/trace/blktrace.c:352
 blk_trace_shutdown+0x67/0x90 kernel/trace/blktrace.c:753
 __blk_release_queue+0x1dc/0x3a0 block/blk-sysfs.c:885
 process_one_work+0x989/0x1790 kernel/workqueue.c:2269
 worker_thread+0x98/0xe40 kernel/workqueue.c:2415
 kthread+0x354/0x420 kernel/kthread.c:255
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352

Allocated by task 20162:
 save_stack+0x23/0x90 mm/kasan/common.c:71
 set_track mm/kasan/common.c:79 [inline]
 __kasan_kmalloc mm/kasan/common.c:489 [inline]
 __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:462
 kasan_slab_alloc+0xf/0x20 mm/kasan/common.c:497
 slab_post_alloc_hook mm/slab.h:437 [inline]
 slab_alloc mm/slab.c:3326 [inline]
 kmem_cache_alloc+0x11a/0x6f0 mm/slab.c:3488
 __d_alloc+0x2e/0x8c0 fs/dcache.c:1622
 d_alloc+0x4d/0x280 fs/dcache.c:1701
 d_alloc_parallel+0xf4/0x1bb0 fs/dcache.c:2455
 __lookup_slow+0x1ab/0x500 fs/namei.c:1652
 lookup_one_len+0x16d/0x1a0 fs/namei.c:2541
 start_creating fs/debugfs/inode.c:307 [inline]
 start_creating+0xbf/0x1e0 fs/debugfs/inode.c:283
 __debugfs_create_file+0x65/0x3d0 fs/debugfs/inode.c:346
 debugfs_create_file+0x5a/0x70 fs/debugfs/inode.c:399
 do_blk_trace_setup+0x376/0xb90 kernel/trace/blktrace.c:528
 compat_blk_trace_setup+0x13e/0x1f0 kernel/trace/blktrace.c:623
 blk_trace_ioctl+0x293/0x300 kernel/trace/blktrace.c:721
 compat_blkdev_ioctl+0x3fb/0x1930 block/compat_ioctl.c:402
 __do_compat_sys_ioctl fs/compat_ioctl.c:1052 [inline]
 __se_compat_sys_ioctl fs/compat_ioctl.c:998 [inline]
 __ia32_compat_sys_ioctl+0x195/0x620 fs/compat_ioctl.c:998
 do_syscall_32_irqs_on arch/x86/entry/common.c:337 [inline]
 do_fast_syscall_32+0x27b/0xd7d arch/x86/entry/common.c:408
 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139

Freed by task 16:
 save_stack+0x23/0x90 mm/kasan/common.c:71
 set_track mm/kasan/common.c:79 [inline]
 __kasan_slab_free+0x102/0x150 mm/kasan/common.c:451
 kasan_slab_free+0xe/0x10 mm/kasan/common.c:459
 __cache_free mm/slab.c:3432 [inline]
 kmem_cache_free+0x86/0x260 mm/slab.c:3698
 __d_free+0x20/0x30 fs/dcache.c:271
 __rcu_reclaim kernel/rcu/rcu.h:222 [inline]
 rcu_do_batch kernel/rcu/tree.c:2092 [inline]
 invoke_rcu_callbacks kernel/rcu/tree.c:2310 [inline]
 rcu_core+0xba5/0x1500 kernel/rcu/tree.c:2291
 __do_softirq+0x25c/0x94c kernel/softirq.c:293

The buggy address belongs to the object at ffff88808839f840
 which belongs to the cache dentry(33:syz2) of size 288
The buggy address is located 64 bytes inside of
 288-byte region [ffff88808839f840, ffff88808839f960)
The buggy address belongs to the page:
page:ffffea000220e7c0 refcount:1 mapcount:0 mapping:ffff88809678f7c0 index:0xffff88808839fdc0
flags: 0x1fffc0000000200(slab)
raw: 01fffc0000000200 ffffea00024e76c8 ffffea0000975008 ffff88809678f7c0
raw: ffff88808839fdc0 ffff88808839f000 0000000100000009 ffff888062315900
page dumped because: kasan: bad access detected
page->mem_cgroup:ffff888062315900

Memory state around the buggy address:
 ffff88808839f780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88808839f800: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
>ffff88808839f880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                   ^
 ffff88808839f900: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
 ffff88808839f980: fc fc fc fc fb fb fb fb fb fb fb fb fb fb fb fb
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