KMSAN: uninit-value in vmx_handle_external

Kernel	Title	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
upstream	KMSAN: uninit-value in vmx_handle_external_intr kvm				3	2302d	2303d	0/28	closed as invalid on 2018/10/10 13:24
TCP: request_sock_TCPv6: Possible SYN flooding on port 20002. Sending cookies.  Check SNMP counters.
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BUG: KMSAN: uninit-value in gate_offset arch/x86/include/asm/desc_defs.h:93 [inline]
BUG: KMSAN: uninit-value in vmx_handle_external_intr+0x244/0x280 arch/x86/kvm/vmx.c:10417
CPU: 0 PID: 7908 Comm: syz-executor5 Not tainted 4.19.0-rc4+ #66
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+0x306/0x460 lib/dump_stack.c:113
 kmsan_report+0x1a2/0x2e0 mm/kmsan/kmsan.c:917
 __msan_warning+0x7c/0xe0 mm/kmsan/kmsan_instr.c:500
 gate_offset arch/x86/include/asm/desc_defs.h:93 [inline]
 vmx_handle_external_intr+0x244/0x280 arch/x86/kvm/vmx.c:10417
 vcpu_enter_guest arch/x86/kvm/x86.c:7621 [inline]
 vcpu_run arch/x86/kvm/x86.c:7711 [inline]
 kvm_arch_vcpu_ioctl_run+0x9d7a/0x10a20 arch/x86/kvm/x86.c:7888
 kvm_vcpu_ioctl+0x11a7/0x20b0 arch/x86/kvm/../../../virt/kvm/kvm_main.c:2590
 vfs_ioctl fs/ioctl.c:46 [inline]
 do_vfs_ioctl+0xcf3/0x2810 fs/ioctl.c:687
 ksys_ioctl fs/ioctl.c:702 [inline]
 __do_sys_ioctl fs/ioctl.c:709 [inline]
 __se_sys_ioctl+0x1da/0x270 fs/ioctl.c:707
 __x64_sys_ioctl+0x4a/0x70 fs/ioctl.c:707
 do_syscall_64+0xbe/0x100 arch/x86/entry/common.c:291
 entry_SYSCALL_64_after_hwframe+0x63/0xe7
RIP: 0033:0x457519
Code: 1d b4 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 b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f7f4b059c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000457519
RDX: 0000000000000000 RSI: 000000000000ae80 RDI: 0000000000000005
RBP: 000000000072bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f7f4b05a6d4
R13: 00000000004bffda R14: 00000000004d00a8 R15: 00000000ffffffff

Uninit was stored to memory at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:255 [inline]
 kmsan_save_stack mm/kmsan/kmsan.c:270 [inline]
 kmsan_internal_chain_origin+0x136/0x240 mm/kmsan/kmsan.c:572
 __msan_chain_origin+0x75/0xd0 mm/kmsan/kmsan_instr.c:337
 vmx_set_constant_host_state+0xf1a/0x1830 arch/x86/kvm/vmx.c:6325
 vmx_vcpu_setup arch/x86/kvm/vmx.c:6618 [inline]
 vmx_create_vcpu+0x3e6f/0x7870 arch/x86/kvm/vmx.c:11010
 kvm_arch_vcpu_create+0x25d/0x2f0 arch/x86/kvm/x86.c:8452
 kvm_vm_ioctl_create_vcpu arch/x86/kvm/../../../virt/kvm/kvm_main.c:2476 [inline]
 kvm_vm_ioctl+0x13fd/0x33d0 arch/x86/kvm/../../../virt/kvm/kvm_main.c:2977
 vfs_ioctl fs/ioctl.c:46 [inline]
 do_vfs_ioctl+0xcf3/0x2810 fs/ioctl.c:687
 ksys_ioctl fs/ioctl.c:702 [inline]
 __do_sys_ioctl fs/ioctl.c:709 [inline]
 __se_sys_ioctl+0x1da/0x270 fs/ioctl.c:707
 __x64_sys_ioctl+0x4a/0x70 fs/ioctl.c:707
 do_syscall_64+0xbe/0x100 arch/x86/entry/common.c:291
 entry_SYSCALL_64_after_hwframe+0x63/0xe7

Local variable description: ----dt@vmx_set_constant_host_state
Variable was created at:
 vmx_set_constant_host_state+0x2b0/0x1830 arch/x86/kvm/vmx.c:6284
 vmx_vcpu_setup arch/x86/kvm/vmx.c:6618 [inline]
 vmx_create_vcpu+0x3e6f/0x7870 arch/x86/kvm/vmx.c:11010
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