==================================================================
BUG: KASAN: slab-out-of-bounds in memcpy include/linux/string.h:376 [inline]
BUG: KASAN: slab-out-of-bounds in pdu_read+0x94/0x100 net/9p/protocol.c:64
Read of size 65502 at addr ffff8880500f15ed by task syz-executor.5/16787

CPU: 0 PID: 16787 Comm: syz-executor.5 Not tainted 4.14.222-syzkaller #0
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+0x1b2/0x281 lib/dump_stack.c:58
 print_address_description.cold+0x54/0x1d3 mm/kasan/report.c:252
 kasan_report_error.cold+0x8a/0x191 mm/kasan/report.c:351
 kasan_report+0x6f/0x80 mm/kasan/report.c:409
 memcpy+0x20/0x50 mm/kasan/kasan.c:302
 memcpy include/linux/string.h:376 [inline]
 pdu_read+0x94/0x100 net/9p/protocol.c:64
 p9pdu_vreadf net/9p/protocol.c:167 [inline]
 p9pdu_readf+0x381/0x1970 net/9p/protocol.c:540
 p9_client_version net/9p/client.c:990 [inline]
 p9_client_create+0x9b2/0x12c0 net/9p/client.c:1088
 v9fs_session_init+0x1c5/0x1540 fs/9p/v9fs.c:422
 v9fs_mount+0x73/0x860 fs/9p/vfs_super.c:135
 mount_fs+0x92/0x2a0 fs/super.c:1237
 vfs_kern_mount.part.0+0x5b/0x470 fs/namespace.c:1046
 vfs_kern_mount fs/namespace.c:1036 [inline]
 do_new_mount fs/namespace.c:2549 [inline]
 do_mount+0xe53/0x2a00 fs/namespace.c:2879
 SYSC_mount fs/namespace.c:3095 [inline]
 SyS_mount+0xa8/0x120 fs/namespace.c:3072
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x465ef9
RSP: 002b:00007f2eb70e3188 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 000000000056bf60 RCX: 0000000000465ef9
RDX: 0000000020000100 RSI: 0000000020000040 RDI: 0000000000000000
RBP: 00000000004bcd1c R08: 0000000020000300 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf60
R13: 00007ffdbc4ded0f R14: 00007f2eb70e3300 R15: 0000000000022000

Allocated by task 16787:
 save_stack mm/kasan/kasan.c:447 [inline]
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_kmalloc+0xeb/0x160 mm/kasan/kasan.c:551
 __do_kmalloc mm/slab.c:3720 [inline]
 __kmalloc+0x15a/0x400 mm/slab.c:3729
 kmalloc include/linux/slab.h:493 [inline]
 p9_fcall_alloc+0x19/0x90 net/9p/client.c:242
 p9_tag_alloc net/9p/client.c:312 [inline]
 p9_client_prepare_req.part.0+0x7f8/0xb60 net/9p/client.c:728
 p9_client_prepare_req net/9p/client.c:718 [inline]
 p9_client_rpc+0x170/0x1520 net/9p/client.c:763
 p9_client_version net/9p/client.c:980 [inline]
 p9_client_create+0x92f/0x12c0 net/9p/client.c:1088
 v9fs_session_init+0x1c5/0x1540 fs/9p/v9fs.c:422
 v9fs_mount+0x73/0x860 fs/9p/vfs_super.c:135
 mount_fs+0x92/0x2a0 fs/super.c:1237
 vfs_kern_mount.part.0+0x5b/0x470 fs/namespace.c:1046
 vfs_kern_mount fs/namespace.c:1036 [inline]
 do_new_mount fs/namespace.c:2549 [inline]
 do_mount+0xe53/0x2a00 fs/namespace.c:2879
 SYSC_mount fs/namespace.c:3095 [inline]
 SyS_mount+0xa8/0x120 fs/namespace.c:3072
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb

Freed by task 9318:
 save_stack mm/kasan/kasan.c:447 [inline]
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_slab_free+0xc3/0x1a0 mm/kasan/kasan.c:524
 __cache_free mm/slab.c:3496 [inline]
 kfree+0xc9/0x250 mm/slab.c:3815
 ops_free+0x182/0x2a0 net/core/net_namespace.c:132
 ops_free_list net/core/net_namespace.c:154 [inline]
 ops_free_list net/core/net_namespace.c:148 [inline]
 cleanup_net+0x464/0x840 net/core/net_namespace.c:488
 process_one_work+0x793/0x14a0 kernel/workqueue.c:2116
 worker_thread+0x5cc/0xff0 kernel/workqueue.c:2250
 kthread+0x30d/0x420 kernel/kthread.c:232
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404

The buggy address belongs to the object at ffff8880500f15c0
 which belongs to the cache kmalloc-16384 of size 16384
The buggy address is located 45 bytes inside of
 16384-byte region [ffff8880500f15c0, ffff8880500f55c0)
The buggy address belongs to the page:
page:ffffea0001403c00 count:1 mapcount:0 mapping:ffff8880500f15c0 index:0x0 compound_mapcount: 0
flags: 0xfff00000008100(slab|head)
raw: 00fff00000008100 ffff8880500f15c0 0000000000000000 0000000100000001
raw: ffffea0001306620 ffffea00014efc20 ffff88813fe08200 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880500f3480: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8880500f3500: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8880500f3580: 00 00 00 00 00 00 00 00 00 00 00 00 fc fc fc fc
                                                       ^
 ffff8880500f3600: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8880500f3680: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================
mmap: syz-executor.4 (16783): VmData 37515264 exceed data ulimit 5. Update limits or use boot option ignore_rlimit_data.
audit: type=1326 audit(1614428063.800:101): auid=4294967295 uid=0 gid=0 ses=4294967295 pid=16783 comm="syz-executor.4" exe="/root/syz-executor.4" sig=9 arch=c000003e syscall=231 compat=0 ip=0x465ef9 code=0x0