RBP: 000000000073bf00 R08: 0000000020000600 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000001a48914
R13: 00000000004c4c14 R14: 00000000004d88a0 R15: 0000000000000004
9pnet: Found fid 0 not clunked
==================================================================
BUG: KASAN: use-after-free in p9_client_clunk+0x131/0x150 net/9p/client.c:1505
Read of size 8 at addr ffff88809ae6ff00 by task syz-executor.0/7625

CPU: 0 PID: 7625 Comm: syz-executor.0 Not tainted 4.14.112 #2
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x138/0x19c lib/dump_stack.c:53
 print_address_description.cold+0x7c/0x1dc mm/kasan/report.c:252
 kasan_report_error mm/kasan/report.c:351 [inline]
 kasan_report mm/kasan/report.c:409 [inline]
 kasan_report.cold+0xaf/0x2b5 mm/kasan/report.c:393
 __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:430
 p9_client_clunk+0x131/0x150 net/9p/client.c:1505
 v9fs_mount+0x6b9/0x870 fs/9p/vfs_super.c:200
 mount_fs+0x9d/0x2a7 fs/super.c:1237
 vfs_kern_mount.part.0+0x5e/0x3d0 fs/namespace.c:1046
 vfs_kern_mount fs/namespace.c:1036 [inline]
 do_new_mount fs/namespace.c:2549 [inline]
 do_mount+0x417/0x27d0 fs/namespace.c:2879
 SYSC_mount fs/namespace.c:3095 [inline]
 SyS_mount+0xab/0x120 fs/namespace.c:3072
 do_syscall_64+0x1eb/0x630 arch/x86/entry/common.c:289
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x458c29
RSP: 002b:00007ffe57dc94f8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007ffe57dc9510 RCX: 0000000000458c29
RDX: 00000000200005c0 RSI: 0000000020000580 RDI: 0000000000000000
RBP: 000000000073bf00 R08: 0000000020000600 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000001a48914
R13: 00000000004c4c14 R14: 00000000004d88a0 R15: 0000000000000004

Allocated by task 7625:
 save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59
 save_stack+0x45/0xd0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_kmalloc mm/kasan/kasan.c:551 [inline]
 kasan_kmalloc+0xce/0xf0 mm/kasan/kasan.c:529
 kmem_cache_alloc_trace+0x152/0x790 mm/slab.c:3618
 kmalloc include/linux/slab.h:488 [inline]
 p9_fid_create+0x4e/0x3b0 net/9p/client.c:918
 p9_client_attach+0x7f/0x6a0 net/9p/client.c:1158
 v9fs_session_init+0xbe8/0x1590 fs/9p/v9fs.c:450
 v9fs_mount+0x7d/0x870 fs/9p/vfs_super.c:135
 mount_fs+0x9d/0x2a7 fs/super.c:1237
 vfs_kern_mount.part.0+0x5e/0x3d0 fs/namespace.c:1046
 vfs_kern_mount fs/namespace.c:1036 [inline]
 do_new_mount fs/namespace.c:2549 [inline]
 do_mount+0x417/0x27d0 fs/namespace.c:2879
 SYSC_mount fs/namespace.c:3095 [inline]
 SyS_mount+0xab/0x120 fs/namespace.c:3072
 do_syscall_64+0x1eb/0x630 arch/x86/entry/common.c:289
 entry_SYSCALL_64_after_hwframe+0x42/0xb7

Freed by task 7625:
 save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59
 save_stack+0x45/0xd0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_slab_free+0x75/0xc0 mm/kasan/kasan.c:524
 __cache_free mm/slab.c:3496 [inline]
 kfree+0xcc/0x270 mm/slab.c:3815
 p9_fid_destroy+0x1cd/0x280 net/9p/client.c:957
 p9_client_destroy.cold+0x61/0xac net/9p/client.c:1121
 v9fs_session_close+0x4a/0x2c0 fs/9p/v9fs.c:490
 v9fs_kill_super+0x4e/0xa0 fs/9p/vfs_super.c:233
 deactivate_locked_super+0x79/0xe0 fs/super.c:319
 sget_userns+0x9df/0xc30 fs/super.c:537
 sget+0xd6/0x120 fs/super.c:572
 v9fs_mount+0xa8/0x870 fs/9p/vfs_super.c:141
 mount_fs+0x9d/0x2a7 fs/super.c:1237
 vfs_kern_mount.part.0+0x5e/0x3d0 fs/namespace.c:1046
 vfs_kern_mount fs/namespace.c:1036 [inline]
 do_new_mount fs/namespace.c:2549 [inline]
 do_mount+0x417/0x27d0 fs/namespace.c:2879
 SYSC_mount fs/namespace.c:3095 [inline]
 SyS_mount+0xab/0x120 fs/namespace.c:3072
 do_syscall_64+0x1eb/0x630 arch/x86/entry/common.c:289
 entry_SYSCALL_64_after_hwframe+0x42/0xb7

The buggy address belongs to the object at ffff88809ae6ff00
 which belongs to the cache kmalloc-96 of size 96
The buggy address is located 0 bytes inside of
 96-byte region [ffff88809ae6ff00, ffff88809ae6ff60)
The buggy address belongs to the page:
page:ffffea00026b9bc0 count:1 mapcount:0 mapping:ffff88809ae6f000 index:0x0
flags: 0x1fffc0000000100(slab)
raw: 01fffc0000000100 ffff88809ae6f000 0000000000000000 0000000100000020
raw: ffffea00026ba060 ffffea00026966a0 ffff8880aa8004c0 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88809ae6fe00: 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc
 ffff88809ae6fe80: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
>ffff88809ae6ff00: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
                   ^
 ffff88809ae6ff80: 00 00 00 00 00 00 00 00 00 01 fc fc fc fc fc fc
 ffff88809ae70000: fc fc fc fc fc fc fc fc 00 00 00 00 00 00 00 00
==================================================================