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BUG: KMSAN: kernel-infoleak in _copy_to_user+0x19a/0x230 lib/usercopy.c:32
CPU: 0 PID: 4011 Comm: syz-executor3 Not tainted 4.20.0-rc3+ #101
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+0x32d/0x480 lib/dump_stack.c:113
 kmsan_report+0x12c/0x290 mm/kmsan/kmsan.c:682
 kmsan_internal_check_memory+0x9ce/0xa50 mm/kmsan/kmsan.c:768
 kmsan_copy_to_user+0x78/0xd0 mm/kmsan/kmsan_hooks.c:634
 _copy_to_user+0x19a/0x230 lib/usercopy.c:32
 kvm_arch_vcpu_ioctl+0x3ef4/0x7300 include/linux/uaccess.h:177
 kvm_vcpu_ioctl+0xbdf/0x1cc0 arch/x86/kvm/../../../virt/kvm/kvm_main.c:2748
 do_vfs_ioctl+0xefc/0x2ca0 fs/ioctl.c:46
 ksys_ioctl fs/ioctl.c:713 [inline]
 __do_sys_ioctl fs/ioctl.c:720 [inline]
 __se_sys_ioctl+0x1da/0x270 fs/ioctl.c:718
 __x64_sys_ioctl+0x4a/0x70 fs/ioctl.c:718
 do_syscall_64+0xcf/0x110 arch/x86/entry/common.c:291
 entry_SYSCALL_64_after_hwframe+0x63/0xe7
RIP: 0033:0x457569
Code: fd b3 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 cb b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f9375d85c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000457569
RDX: 0000000020000180 RSI: 000000004068aea3 RDI: 0000000000000007
RBP: 000000000072bfa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f9375d866d4
R13: 00000000004bff9d R14: 00000000004d0970 R15: 00000000ffffffff

Local variable description: ----__pu_val@kvm_arch_vcpu_ioctl
Variable was created at:
 kvm_arch_vcpu_ioctl+0x2cc/0x7300 arch/x86/kvm/x86.c:3848
 kvm_vcpu_ioctl+0xbdf/0x1cc0 arch/x86/kvm/../../../virt/kvm/kvm_main.c:2748

Bytes 0-1 of 2 are uninitialized
Memory access of size 2 starts at ffff88808736fba0
Data copied to user address 0000000000710000
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