kvm [12758]: vcpu0, guest rIP: 0xc5 Hyper-V unhandled rdmsr: 0x40000007 TCP: request_sock_TCPv6: Possible SYN flooding on port 20002. Sending cookies. Check SNMP counters. kvm [12758]: vcpu0, guest rIP: 0xc5 Hyper-V unhandled rdmsr: 0x40000008 ================================================================== kvm [12758]: vcpu0, guest rIP: 0xc5 Hyper-V unhandled rdmsr: 0x40000009 BUG: KASAN: use-after-free in tcp_skb_pcount include/net/tcp.h:911 [inline] BUG: KASAN: use-after-free in tcp_init_tso_segs+0x1ae/0x200 net/ipv4/tcp_output.c:1790 Read of size 2 at addr ffff8880404d3d30 by task syz-executor.0/12781 CPU: 1 PID: 12781 Comm: syz-executor.0 Not tainted 4.14.143 #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+0x138/0x197 lib/dump_stack.c:53 kvm [12758]: vcpu0, guest rIP: 0xc5 Hyper-V unhandled rdmsr: 0x4000000a 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+0xa9/0x2af mm/kasan/report.c:393 __asan_report_load2_noabort+0x14/0x20 mm/kasan/report.c:428 tcp_skb_pcount include/net/tcp.h:911 [inline] tcp_init_tso_segs+0x1ae/0x200 net/ipv4/tcp_output.c:1790 tcp_write_xmit+0x15e/0x4960 net/ipv4/tcp_output.c:2330 kvm [12758]: vcpu0, guest rIP: 0xc5 Hyper-V unhandled rdmsr: 0x4000000b __tcp_push_pending_frames+0xa6/0x260 net/ipv4/tcp_output.c:2563 tcp_send_fin+0x17e/0xc40 net/ipv4/tcp_output.c:3115 tcp_close+0xcc8/0xfb0 net/ipv4/tcp.c:2221 kvm [12758]: vcpu0, guest rIP: 0xc5 Hyper-V unhandled rdmsr: 0x4000000c tls_sk_proto_close+0x157/0x750 net/tls/tls_main.c:295 inet_release+0xec/0x1c0 net/ipv4/af_inet.c:425 kvm [12758]: vcpu0, guest rIP: 0xc5 Hyper-V unhandled rdmsr: 0x4000000d inet6_release+0x53/0x80 net/ipv6/af_inet6.c:450 __sock_release+0xce/0x2b0 net/socket.c:602 sock_close+0x1b/0x30 net/socket.c:1139 __fput+0x275/0x7a0 fs/file_table.c:210 ____fput+0x16/0x20 fs/file_table.c:244 task_work_run+0x114/0x190 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:191 [inline] exit_to_usermode_loop+0x1da/0x220 arch/x86/entry/common.c:164 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline] syscall_return_slowpath arch/x86/entry/common.c:270 [inline] do_syscall_64+0x4bc/0x640 arch/x86/entry/common.c:297 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x4135d1 RSP: 002b:00007ffcc546c3c0 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 0000000000000004 RCX: 00000000004135d1 RDX: 0000001b32520000 RSI: 0000000000000000 RDI: 0000000000000003 RBP: 0000000000000001 R08: 000000006e783fbb R09: 000000006e783fbf R10: 00007ffcc546c4a0 R11: 0000000000000293 R12: 000000000075bf20 R13: 000000000004bcae R14: 0000000000760628 R15: ffffffffffffffff Allocated by task 12785: 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 kasan_slab_alloc+0xf/0x20 mm/kasan/kasan.c:489 kmem_cache_alloc_node+0x144/0x780 mm/slab.c:3642 kvm [12758]: vcpu0, guest rIP: 0xc5 Hyper-V unhandled rdmsr: 0x4000000e __alloc_skb+0x9c/0x500 net/core/skbuff.c:193 alloc_skb_fclone include/linux/skbuff.h:1022 [inline] sk_stream_alloc_skb+0xb3/0x780 net/ipv4/tcp.c:855 tcp_sendmsg_locked+0xf61/0x3200 net/ipv4/tcp.c:1301 tcp_sendmsg+0x30/0x50 net/ipv4/tcp.c:1457 inet_sendmsg+0x122/0x500 net/ipv4/af_inet.c:762 sock_sendmsg_nosec net/socket.c:646 [inline] sock_sendmsg+0xce/0x110 net/socket.c:656 SYSC_sendto+0x206/0x310 net/socket.c:1763 SyS_sendto+0x40/0x50 net/socket.c:1731 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 Freed by task 12785: save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59 kvm [12758]: vcpu0, guest rIP: 0xcc Hyper-V uhandled wrmsr: 0x40000020 data 0x282e40 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] kmem_cache_free+0x83/0x2b0 mm/slab.c:3758 kfree_skbmem+0x8d/0x120 net/core/skbuff.c:607 __kfree_skb+0x1e/0x30 net/core/skbuff.c:646 sk_wmem_free_skb include/net/sock.h:1416 [inline] tcp_remove_empty_skb.part.0+0x231/0x2e0 net/ipv4/tcp.c:929 tcp_remove_empty_skb net/ipv4/tcp.c:925 [inline] tcp_sendmsg_locked+0x1ced/0x3200 net/ipv4/tcp.c:1435 tcp_sendmsg+0x30/0x50 net/ipv4/tcp.c:1457 inet_sendmsg+0x122/0x500 net/ipv4/af_inet.c:762 sock_sendmsg_nosec net/socket.c:646 [inline] sock_sendmsg+0xce/0x110 net/socket.c:656 kobject: 'kvm' (ffff8880a6e282d0): kobject_uevent_env SYSC_sendto+0x206/0x310 net/socket.c:1763 kobject: 'kvm' (ffff8880a6e282d0): fill_kobj_path: path = '/devices/virtual/misc/kvm' SyS_sendto+0x40/0x50 net/socket.c:1731 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 The buggy address belongs to the object at ffff8880404d3d00 which belongs to the cache skbuff_fclone_cache of size 472 The buggy address is located 48 bytes inside of 472-byte region [ffff8880404d3d00, ffff8880404d3ed8) The buggy address belongs to the page: page:ffffea00010134c0 count:1 mapcount:0 mapping:ffff8880404d3080 index:0x0 flags: 0x1fffc0000000100(slab) raw: 01fffc0000000100 ffff8880404d3080 0000000000000000 0000000100000006 raw: ffffea000231cea0 ffffea000130c320 ffff88821b7203c0 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8880404d3c00: fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc fc ffff8880404d3c80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff8880404d3d00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880404d3d80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880404d3e00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================