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BUG: KASAN: use-after-free in __lock_acquire+0x96/0x1bc0 kernel/locking/lockdep.c:3827
Read of size 8 at addr ffff888096c96398 by task syz-executor.3/15595

CPU: 1 PID: 15595 Comm: syz-executor.3 Not tainted 5.6.0-rc6-syzkaller #0
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+0x1e9/0x30e lib/dump_stack.c:118
 print_address_description+0x74/0x5c0 mm/kasan/report.c:374
 __kasan_report+0x14b/0x1c0 mm/kasan/report.c:506
 kasan_report+0x25/0x50 mm/kasan/common.c:641
 __lock_acquire+0x96/0x1bc0 kernel/locking/lockdep.c:3827
 lock_acquire+0x154/0x250 kernel/locking/lockdep.c:4484
 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
 _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:151
 spin_lock include/linux/spinlock.h:338 [inline]
 lockref_get+0x11/0x50 lib/lockref.c:52
 dget include/linux/dcache.h:321 [inline]
 simple_recursive_removal+0x31/0x6e0 fs/libfs.c:268
 debugfs_remove+0x45/0x60 fs/debugfs/inode.c:713
 blk_trace_free kernel/trace/blktrace.c:312 [inline]
 do_blk_trace_setup+0x7b6/0x9b0 kernel/trace/blktrace.c:557
 __blk_trace_setup kernel/trace/blktrace.c:571 [inline]
 blk_trace_ioctl+0x24c/0x7d0 kernel/trace/blktrace.c:712
 blkdev_ioctl+0x101/0x5c0 block/ioctl.c:710
 block_ioctl+0xb6/0xf0 fs/block_dev.c:1983
 vfs_ioctl fs/ioctl.c:47 [inline]
 ksys_ioctl fs/ioctl.c:763 [inline]
 __do_sys_ioctl fs/ioctl.c:772 [inline]
 __se_sys_ioctl+0xf9/0x160 fs/ioctl.c:770
 do_syscall_64+0xf3/0x1b0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45c849
Code: ad b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f7745ed1c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f7745ed26d4 RCX: 000000000045c849
RDX: 0000000020000080 RSI: 00000000c0481273 RDI: 0000000000000008
RBP: 000000000076bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000228 R14: 00000000004c44eb R15: 000000000076bf0c

Allocated by task 15595:
 save_stack mm/kasan/common.c:72 [inline]
 set_track mm/kasan/common.c:80 [inline]
 __kasan_kmalloc+0x118/0x1c0 mm/kasan/common.c:515
 slab_post_alloc_hook mm/slab.h:584 [inline]
 slab_alloc mm/slab.c:3320 [inline]
 kmem_cache_alloc+0x1f5/0x2d0 mm/slab.c:3484
 __d_alloc+0x2a/0x6d0 fs/dcache.c:1690
 d_alloc fs/dcache.c:1769 [inline]
 d_alloc_parallel+0x81/0x13b0 fs/dcache.c:2521
 __lookup_slow+0xaa/0x370 fs/namei.c:1742
 lookup_one_len+0x10e/0x200 fs/namei.c:2661
 start_creating+0x10f/0x2c0 fs/debugfs/inode.c:338
 __debugfs_create_file+0x74/0x470 fs/debugfs/inode.c:383
 do_blk_trace_setup+0x396/0x9b0 kernel/trace/blktrace.c:521
 __blk_trace_setup kernel/trace/blktrace.c:571 [inline]
 blk_trace_ioctl+0x24c/0x7d0 kernel/trace/blktrace.c:712
 blkdev_ioctl+0x101/0x5c0 block/ioctl.c:710
 block_ioctl+0xb6/0xf0 fs/block_dev.c:1983
 vfs_ioctl fs/ioctl.c:47 [inline]
 ksys_ioctl fs/ioctl.c:763 [inline]
 __do_sys_ioctl fs/ioctl.c:772 [inline]
 __se_sys_ioctl+0xf9/0x160 fs/ioctl.c:770
 do_syscall_64+0xf3/0x1b0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 16:
 save_stack mm/kasan/common.c:72 [inline]
 set_track mm/kasan/common.c:80 [inline]
 kasan_set_free_info mm/kasan/common.c:337 [inline]
 __kasan_slab_free+0x12e/0x1e0 mm/kasan/common.c:476
 __cache_free mm/slab.c:3426 [inline]
 kmem_cache_free+0x7e/0xf0 mm/slab.c:3694
 rcu_do_batch kernel/rcu/tree.c:2186 [inline]
 rcu_core+0x7e4/0x1080 kernel/rcu/tree.c:2410
 __do_softirq+0x268/0x7c5 kernel/softirq.c:292

The buggy address belongs to the object at ffff888096c96300
 which belongs to the cache dentry(81:syz3) of size 288
The buggy address is located 152 bytes inside of
 288-byte region [ffff888096c96300, ffff888096c96420)
The buggy address belongs to the page:
page:ffffea00025b2580 refcount:1 mapcount:0 mapping:ffff88808b874700 index:0x0
flags: 0xfffe0000000200(slab)
raw: 00fffe0000000200 ffffea00025b0c08 ffffea000286ecc8 ffff88808b874700
raw: 0000000000000000 ffff888096c96040 000000010000000b 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff888096c96280: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
 ffff888096c96300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888096c96380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                            ^
 ffff888096c96400: fb fb fb fb fc fc fc fc fc fc fc fc 00 00 00 00
 ffff888096c96480: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
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