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BUG: KASAN: use-after-free in __lock_acquire+0x32a3/0x3ca0 kernel/locking/lockdep.c:3827
Read of size 8 at addr ffff8880865f3e58 by task syz-executor.4/23108

CPU: 0 PID: 23108 Comm: syz-executor.4 Not tainted 5.6.0-rc7-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+0x188/0x20d lib/dump_stack.c:118
 print_address_description.constprop.0.cold+0xd3/0x315 mm/kasan/report.c:374
 __kasan_report.cold+0x1a/0x32 mm/kasan/report.c:506
 kasan_report+0xe/0x20 mm/kasan/common.c:641
 __lock_acquire+0x32a3/0x3ca0 kernel/locking/lockdep.c:3827
 lock_acquire+0x197/0x420 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
 lockref_get+0x11/0x50 include/linux/spinlock.h:338
 dget include/linux/dcache.h:321 [inline]
 simple_recursive_removal+0x40/0x720 fs/libfs.c:268
 debugfs_remove fs/debugfs/inode.c:713 [inline]
 debugfs_remove+0x59/0x80 fs/debugfs/inode.c:707
 blk_trace_free+0x31/0x130 kernel/trace/blktrace.c:311
 do_blk_trace_setup+0x711/0xb30 kernel/trace/blktrace.c:557
 __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:710
 block_ioctl+0xe9/0x130 fs/block_dev.c:1983
 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: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:00007f76014a7c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f76014a86d4 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 23108:
 save_stack+0x1b/0x80 mm/kasan/common.c:72
 set_track mm/kasan/common.c:80 [inline]
 __kasan_kmalloc mm/kasan/common.c:515 [inline]
 __kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:488
 slab_post_alloc_hook mm/slab.h:584 [inline]
 slab_alloc mm/slab.c:3320 [inline]
 kmem_cache_alloc+0x11b/0x730 mm/slab.c:3484
 __d_alloc+0x2b/0x8d0 fs/dcache.c:1690
 d_alloc+0x4a/0x240 fs/dcache.c:1769
 d_alloc_parallel+0xe8/0x1b10 fs/dcache.c:2521
 __lookup_slow+0x18d/0x480 fs/namei.c:1742
 lookup_one_len+0x163/0x190 fs/namei.c:2661
 start_creating+0x12b/0x250 fs/debugfs/inode.c:338
 __debugfs_create_file+0x62/0x3f0 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:710
 block_ioctl+0xe9/0x130 fs/block_dev.c:1983
 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:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 23108:
 save_stack+0x1b/0x80 mm/kasan/common.c:72
 set_track mm/kasan/common.c:80 [inline]
 kasan_set_free_info mm/kasan/common.c:337 [inline]
 __kasan_slab_free+0xf7/0x140 mm/kasan/common.c:476
 __cache_free mm/slab.c:3426 [inline]
 kmem_cache_free+0x7f/0x320 mm/slab.c:3694
 rcu_do_batch kernel/rcu/tree.c:2186 [inline]
 rcu_core+0x5a4/0x12d0 kernel/rcu/tree.c:2410
 __do_softirq+0x26c/0x99d kernel/softirq.c:292

The buggy address belongs to the object at ffff8880865f3dc0
 which belongs to the cache dentry of size 288
The buggy address is located 152 bytes inside of
 288-byte region [ffff8880865f3dc0, ffff8880865f3ee0)
The buggy address belongs to the page:
page:ffffea0002197cc0 refcount:1 mapcount:0 mapping:ffff8880aa1f8a80 index:0x0
flags: 0xfffe0000000200(slab)
raw: 00fffe0000000200 ffffea0002197c88 ffffea0002197d08 ffff8880aa1f8a80
raw: 0000000000000000 ffff8880865f3000 000000010000000b 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880865f3d00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8880865f3d80: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
>ffff8880865f3e00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                    ^
 ffff8880865f3e80: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
 ffff8880865f3f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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