REISERFS warning (device loop6): sh-2011 read_super_block: can't find a reiserfs filesystem on (dev loop6, block 16, size 4096)
REISERFS warning (device loop6): sh-2021 reiserfs_fill_super: can not find reiserfs on loop6
REISERFS warning (device loop6): sh-2011 read_super_block: can't find a reiserfs filesystem on (dev loop6, block 16, size 4096)
REISERFS warning (device loop6): sh-2021 reiserfs_fill_super: can not find reiserfs on loop6
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BUG: KASAN: use-after-free in debug_spin_lock_before kernel/locking/spinlock_debug.c:83 [inline]
BUG: KASAN: use-after-free in do_raw_spin_lock+0x1c0/0x200 kernel/locking/spinlock_debug.c:112
Read of size 4 at addr ffff8801ad27ebc4 by task kworker/1:4/15982

CPU: 1 PID: 15982 Comm: kworker/1:4 Not tainted 4.18.0-rc8+ #180
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events p9_poll_workfn
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1c9/0x2b4 lib/dump_stack.c:113
 print_address_description+0x6c/0x20b mm/kasan/report.c:256
 kasan_report_error mm/kasan/report.c:354 [inline]
 kasan_report.cold.7+0x242/0x2fe mm/kasan/report.c:412
 __asan_report_load4_noabort+0x14/0x20 mm/kasan/report.c:432
 debug_spin_lock_before kernel/locking/spinlock_debug.c:83 [inline]
 do_raw_spin_lock+0x1c0/0x200 kernel/locking/spinlock_debug.c:112
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:117 [inline]
 _raw_spin_lock_irqsave+0x9e/0xc0 kernel/locking/spinlock.c:152
 p9_conn_cancel+0x166/0xd30 net/9p/trans_fd.c:205
 p9_poll_mux net/9p/trans_fd.c:620 [inline]
 p9_poll_workfn+0x4b2/0x6d0 net/9p/trans_fd.c:1107
 process_one_work+0xc73/0x1ba0 kernel/workqueue.c:2153
 worker_thread+0x189/0x13c0 kernel/workqueue.c:2296
 kthread+0x345/0x410 kernel/kthread.c:246
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:412

Allocated by task 25503:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:448
 set_track mm/kasan/kasan.c:460 [inline]
 kasan_kmalloc+0xc4/0xe0 mm/kasan/kasan.c:553
 kmem_cache_alloc_trace+0x152/0x780 mm/slab.c:3620
 kmalloc include/linux/slab.h:513 [inline]
 p9_client_create+0x114/0x1770 net/9p/client.c:1023
 v9fs_session_init+0x21a/0x1a80 fs/9p/v9fs.c:400
 v9fs_mount+0x7c/0x900 fs/9p/vfs_super.c:135
 mount_fs+0xae/0x328 fs/super.c:1277
 vfs_kern_mount.part.34+0xdc/0x4e0 fs/namespace.c:1037
 vfs_kern_mount fs/namespace.c:1027 [inline]
 do_new_mount fs/namespace.c:2518 [inline]
 do_mount+0x581/0x30e0 fs/namespace.c:2848
 ksys_mount+0x12d/0x140 fs/namespace.c:3064
 __do_sys_mount fs/namespace.c:3078 [inline]
 __se_sys_mount fs/namespace.c:3075 [inline]
 __x64_sys_mount+0xbe/0x150 fs/namespace.c:3075
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 25503:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:448
 set_track mm/kasan/kasan.c:460 [inline]
 __kasan_slab_free+0x11a/0x170 mm/kasan/kasan.c:521
 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528
 __cache_free mm/slab.c:3498 [inline]
 kfree+0xd9/0x260 mm/slab.c:3813
 p9_client_create+0x2fa/0x1770 net/9p/client.c:1085
 v9fs_session_init+0x21a/0x1a80 fs/9p/v9fs.c:400
 v9fs_mount+0x7c/0x900 fs/9p/vfs_super.c:135
 mount_fs+0xae/0x328 fs/super.c:1277
 vfs_kern_mount.part.34+0xdc/0x4e0 fs/namespace.c:1037
 vfs_kern_mount fs/namespace.c:1027 [inline]
 do_new_mount fs/namespace.c:2518 [inline]
 do_mount+0x581/0x30e0 fs/namespace.c:2848
 ksys_mount+0x12d/0x140 fs/namespace.c:3064
 __do_sys_mount fs/namespace.c:3078 [inline]
 __se_sys_mount fs/namespace.c:3075 [inline]
 __x64_sys_mount+0xbe/0x150 fs/namespace.c:3075
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff8801ad27ebc0
 which belongs to the cache kmalloc-4096 of size 4096
The buggy address is located 4 bytes inside of
 4096-byte region [ffff8801ad27ebc0, ffff8801ad27fbc0)
The buggy address belongs to the page:
page:ffffea0006b49f80 count:1 mapcount:0 mapping:ffff8801dac00dc0 index:0x0 compound_mapcount: 0
flags: 0x2fffc0000008100(slab|head)
raw: 02fffc0000008100 ffffea0006b31a88 ffffea0006c4c788 ffff8801dac00dc0
raw: 0000000000000000 ffff8801ad27ebc0 0000000100000001 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801ad27ea80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8801ad27eb00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff8801ad27eb80: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
                                           ^
 ffff8801ad27ec00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8801ad27ec80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================