FS-Cache: O-key=[10] '34323934383237303738'
FS-Cache: N-cookie c=00000000062b18c9 [p=0000000059445219 fl=2 nc=0 na=1]
FS-Cache: N-cookie d=000000005f3c18a9 n=00000000b4bf9863
FS-Cache: N-key=[10] '34323934383237303738'
==================================================================
BUG: KASAN: use-after-free in p9_conn_cancel+0x9de/0xd30 net/9p/trans_fd.c:207
Read of size 4 at addr ffff8801cb967ce8 by task kworker/0:4/5057

CPU: 0 PID: 5057 Comm: kworker/0:4 Not tainted 4.18.0-rc4+ #42
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
 p9_conn_cancel+0x9de/0xd30 net/9p/trans_fd.c:207
 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 4580:
 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]
 kzalloc include/linux/slab.h:707 [inline]
 p9_fd_open net/9p/trans_fd.c:796 [inline]
 p9_fd_create+0x1a7/0x3f0 net/9p/trans_fd.c:1036
 p9_client_create+0x915/0x16c9 net/9p/client.c:1062
 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
 __do_compat_sys_mount fs/compat.c:125 [inline]
 __se_compat_sys_mount fs/compat.c:92 [inline]
 __ia32_compat_sys_mount+0x5d5/0x860 fs/compat.c:92
 do_syscall_32_irqs_on arch/x86/entry/common.c:326 [inline]
 do_fast_syscall_32+0x34d/0xfb2 arch/x86/entry/common.c:397
 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139

Freed by task 4580:
 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_fd_close+0x416/0x5b0 net/9p/trans_fd.c:893
 p9_client_destroy+0x73/0x610 net/9p/client.c:1096
 v9fs_session_close+0x99/0x420 fs/9p/v9fs.c:492
 v9fs_mount+0x4dd/0x900 fs/9p/vfs_super.c:201
 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
 __do_compat_sys_mount fs/compat.c:125 [inline]
 __se_compat_sys_mount fs/compat.c:92 [inline]
 __ia32_compat_sys_mount+0x5d5/0x860 fs/compat.c:92
 do_syscall_32_irqs_on arch/x86/entry/common.c:326 [inline]
 do_fast_syscall_32+0x34d/0xfb2 arch/x86/entry/common.c:397
 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139

The buggy address belongs to the object at ffff8801cb967cc0
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 40 bytes inside of
 512-byte region [ffff8801cb967cc0, ffff8801cb967ec0)
The buggy address belongs to the page:
page:ffffea00072e59c0 count:1 mapcount:0 mapping:ffff8801da800940 index:0x0
flags: 0x2fffc0000000100(slab)
raw: 02fffc0000000100 ffffea0007626d48 ffffea00073c1c88 ffff8801da800940
raw: 0000000000000000 ffff8801cb967040 0000000100000006 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801cb967b80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8801cb967c00: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
>ffff8801cb967c80: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
                                                          ^
 ffff8801cb967d00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8801cb967d80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================