==================================================================
BUG: KASAN: slab-out-of-bounds in memcpy include/linux/string.h:345 [inline]
BUG: KASAN: slab-out-of-bounds in pdu_read+0x90/0xd0 net/9p/protocol.c:59
Read of size 19712 at addr ffff880192abb26d by task syz-executor1/13166

CPU: 1 PID: 13166 Comm: syz-executor1 Not tainted 4.18.0-rc5-next-20180720+ #12
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+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+0x242/0x30d mm/kasan/report.c:412
 check_memory_region_inline mm/kasan/kasan.c:260 [inline]
 check_memory_region+0x13e/0x1b0 mm/kasan/kasan.c:267
 memcpy+0x23/0x50 mm/kasan/kasan.c:302
 memcpy include/linux/string.h:345 [inline]
 pdu_read+0x90/0xd0 net/9p/protocol.c:59
 p9pdu_vreadf net/9p/protocol.c:162 [inline]
 p9pdu_readf+0x579/0x2170 net/9p/protocol.c:536
 p9_client_version net/9p/client.c:900 [inline]
 p9_client_create+0x6d0/0x1537 net/9p/client.c:974
 v9fs_session_init+0x21a/0x1a80 fs/9p/v9fs.c:400
 v9fs_mount+0x7c/0x900 fs/9p/vfs_super.c:135
 legacy_get_tree+0x131/0x460 fs/fs_context.c:674
 vfs_get_tree+0x1cb/0x5c0 fs/super.c:1743
 do_new_mount fs/namespace.c:2603 [inline]
 do_mount+0x6f2/0x1e20 fs/namespace.c:2927
 ksys_mount+0x12d/0x140 fs/namespace.c:3143
 __do_sys_mount fs/namespace.c:3157 [inline]
 __se_sys_mount fs/namespace.c:3154 [inline]
 __x64_sys_mount+0xbe/0x150 fs/namespace.c:3154
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x455ab9
Code: 1d ba 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 eb b9 fb ff c3 66 2e 0f 1f 84 00 00 00 00 
RSP: 002b:00007f6a667acc68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f6a667ad6d4 RCX: 0000000000455ab9
RDX: 0000000020000900 RSI: 0000000020000000 RDI: 0000000000000000
RBP: 000000000072bf50 R08: 0000000020000840 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000004c0201 R14: 00000000004cfe50 R15: 0000000000000001

Allocated by task 13166:
 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
 __do_kmalloc mm/slab.c:3718 [inline]
 __kmalloc+0x14e/0x760 mm/slab.c:3727
 kmalloc include/linux/slab.h:518 [inline]
 p9_fcall_alloc+0x1e/0x90 net/9p/client.c:237
 p9_tag_alloc net/9p/client.c:267 [inline]
 p9_client_prepare_req.part.8+0x132/0xa00 net/9p/client.c:640
 p9_client_prepare_req net/9p/client.c:675 [inline]
 p9_client_rpc+0x242/0x1330 net/9p/client.c:675
 p9_client_version net/9p/client.c:890 [inline]
 p9_client_create+0xca4/0x1537 net/9p/client.c:974
 v9fs_session_init+0x21a/0x1a80 fs/9p/v9fs.c:400
 v9fs_mount+0x7c/0x900 fs/9p/vfs_super.c:135
 legacy_get_tree+0x131/0x460 fs/fs_context.c:674
 vfs_get_tree+0x1cb/0x5c0 fs/super.c:1743
 do_new_mount fs/namespace.c:2603 [inline]
 do_mount+0x6f2/0x1e20 fs/namespace.c:2927
 ksys_mount+0x12d/0x140 fs/namespace.c:3143
 __do_sys_mount fs/namespace.c:3157 [inline]
 __se_sys_mount fs/namespace.c:3154 [inline]
 __x64_sys_mount+0xbe/0x150 fs/namespace.c:3154
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 12005:
 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
 skb_free_head+0x99/0xc0 net/core/skbuff.c:550
 skb_release_data+0x6a4/0x880 net/core/skbuff.c:570
 skb_release_all+0x4a/0x60 net/core/skbuff.c:627
 __kfree_skb net/core/skbuff.c:641 [inline]
 consume_skb+0x193/0x560 net/core/skbuff.c:701
 skb_free_datagram+0x1a/0xf0 net/core/datagram.c:329
 netlink_recvmsg+0x70f/0x1490 net/netlink/af_netlink.c:1980
 sock_recvmsg_nosec net/socket.c:796 [inline]
 sock_recvmsg+0xd0/0x110 net/socket.c:803
 ___sys_recvmsg+0x2b6/0x680 net/socket.c:2269
 __sys_recvmsg+0x11a/0x290 net/socket.c:2318
 __do_sys_recvmsg net/socket.c:2328 [inline]
 __se_sys_recvmsg net/socket.c:2325 [inline]
 __x64_sys_recvmsg+0x78/0xb0 net/socket.c:2325
 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 ffff880192abb240
 which belongs to the cache kmalloc-16384 of size 16384
The buggy address is located 45 bytes inside of
 16384-byte region [ffff880192abb240, ffff880192abf240)
The buggy address belongs to the page:
page:ffffea00064aae00 count:1 mapcount:0 mapping:ffff8801da802200 index:0x0 compound_mapcount: 0
flags: 0x2fffc0000010200(slab|head)
raw: 02fffc0000010200 ffffea0006555a08 ffffea00064b6608 ffff8801da802200
raw: 0000000000000000 ffff880192abb240 0000000100000001 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff880192abd100: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff880192abd180: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff880192abd200: 00 00 00 00 00 00 00 00 00 00 00 00 fc fc fc fc
                                                       ^
 ffff880192abd280: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff880192abd300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================