ALSA: seq fatal error: cannot create timer (-22)
ALSA: seq fatal error: cannot create timer (-22)
==================================================================
BUG: KASAN: use-after-free in debugfs_remove+0x10d/0x130 fs/debugfs/inode.c:685
Read of size 8 at addr ffff888095c71900 by task syz-executor.4/29736

CPU: 0 PID: 29736 Comm: syz-executor.4 Not tainted 5.0.0-rc8+ #1
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
 debugfs_remove+0x10d/0x130 fs/debugfs/inode.c:685
 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_ioctl+0x239/0x300 kernel/trace/blktrace.c:730
 blkdev_ioctl+0x12c/0x1c40 block/ioctl.c:591
 block_ioctl+0xee/0x130 fs/block_dev.c:1914
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:509 [inline]
 do_vfs_ioctl+0xd6e/0x1390 fs/ioctl.c:696
 ksys_ioctl+0xab/0xd0 fs/ioctl.c:713
 __do_sys_ioctl fs/ioctl.c:720 [inline]
 __se_sys_ioctl fs/ioctl.c:718 [inline]
 __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:718
 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x457e29
Code: ad b8 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 b8 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f5d18fcbc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000457e29
RDX: 0000000000000000 RSI: 0000000000001276 RDI: 0000000000000006
RBP: 000000000073bfa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f5d18fcc6d4
R13: 00000000004bf30c R14: 00000000004d0d58 R15: 00000000ffffffff

Allocated by task 29673:
 save_stack+0x45/0xd0 mm/kasan/common.c:73
 set_track mm/kasan/common.c:85 [inline]
 __kasan_kmalloc mm/kasan/common.c:495 [inline]
 __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:468
 kasan_slab_alloc+0xf/0x20 mm/kasan/common.c:503
 slab_post_alloc_hook mm/slab.h:440 [inline]
 slab_alloc mm/slab.c:3388 [inline]
 kmem_cache_alloc+0x11a/0x6f0 mm/slab.c:3548
 __d_alloc+0x2e/0x8c0 fs/dcache.c:1622
 d_alloc+0x4d/0x2b0 fs/dcache.c:1701
 d_alloc_parallel+0xf4/0x1bc0 fs/dcache.c:2449
 __lookup_slow+0x1ab/0x500 fs/namei.c:1654
 lookup_one_len+0x16d/0x1a0 fs/namei.c:2543
 start_creating fs/debugfs/inode.c:308 [inline]
 start_creating+0xbf/0x1e0 fs/debugfs/inode.c:284
 __debugfs_create_file+0x65/0x400 fs/debugfs/inode.c:347
 debugfs_create_file+0x5a/0x70 fs/debugfs/inode.c:400
 do_blk_trace_setup+0x376/0xb90 kernel/trace/blktrace.c:528
 __blk_trace_setup+0xe3/0x190 kernel/trace/blktrace.c:577
 blk_trace_ioctl+0x170/0x300 kernel/trace/blktrace.c:716
 blkdev_ioctl+0x12c/0x1c40 block/ioctl.c:591
 block_ioctl+0xee/0x130 fs/block_dev.c:1914
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:509 [inline]
 do_vfs_ioctl+0xd6e/0x1390 fs/ioctl.c:696
 ksys_ioctl+0xab/0xd0 fs/ioctl.c:713
 __do_sys_ioctl fs/ioctl.c:720 [inline]
 __se_sys_ioctl fs/ioctl.c:718 [inline]
 __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:718
 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 9:
 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:457
 kasan_slab_free+0xe/0x10 mm/kasan/common.c:465
 __cache_free mm/slab.c:3494 [inline]
 kmem_cache_free+0x86/0x260 mm/slab.c:3754
 __d_free+0x20/0x30 fs/dcache.c:269
 __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

The buggy address belongs to the object at ffff888095c718c0
 which belongs to the cache dentry(87:syz4) of size 288
The buggy address is located 64 bytes inside of
 288-byte region [ffff888095c718c0, ffff888095c719e0)
The buggy address belongs to the page:
page:ffffea0002571c40 count:1 mapcount:0 mapping:ffff888086953900 index:0xffff888095c714a0
flags: 0x1fffc0000000200(slab)
raw: 01fffc0000000200 ffffea000232c448 ffffea0002573508 ffff888086953900
raw: ffff888095c714a0 ffff888095c71080 0000000100000009 ffff88809ac46480
page dumped because: kasan: bad access detected
page->mem_cgroup:ffff88809ac46480

Memory state around the buggy address:
 ffff888095c71800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888095c71880: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
>ffff888095c71900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                   ^
 ffff888095c71980: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
 ffff888095c71a00: fc fc fc fc fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================