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Mon, 22 Jan 2024 00:20:24 -0800 (PST) Date: Mon, 22 Jan 2024 00:20:24 -0800 In-Reply-To: <0000000000009c91ce060e87575b@google.com> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <000000000000671a09060f84808b@google.com> Subject: Re: [syzbot] [kvm?] KMSAN: uninit-value in em_ret_far From: syzbot To: bp@alien8.de, dave.hansen@linux.intel.com, glider@google.com, hpa@zytor.com, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, mingo@redhat.com, n.zhandarovich@fintech.ru, nogikh@google.com, pbonzini@redhat.com, seanjc@google.com, syzkaller-bugs@googlegroups.com, tglx@linutronix.de, x86@kernel.org Content-Type: text/plain; charset="UTF-8" syzbot has found a reproducer for the following issue on: HEAD commit: 9f8413c4a66f Merge tag 'cgroup-for-6.8' of git://git.kerne.. git tree: upstream console+strace: https://syzkaller.appspot.com/x/log.txt?x=174e24d7e80000 kernel config: https://syzkaller.appspot.com/x/.config?x=656820e61b758b15 dashboard link: https://syzkaller.appspot.com/bug?extid=579eb95e588b48b4499c compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=13ffebbde80000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=143dcfc7e80000 Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/79d9f2f4b065/disk-9f8413c4.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/cbc68430d9c6/vmlinux-9f8413c4.xz kernel image: https://storage.googleapis.com/syzbot-assets/9740ad9fc172/bzImage-9f8413c4.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+579eb95e588b48b4499c@syzkaller.appspotmail.com ===================================================== BUG: KMSAN: uninit-value in em_ret_far+0x332/0x340 arch/x86/kvm/emulate.c:2258 em_ret_far+0x332/0x340 arch/x86/kvm/emulate.c:2258 em_ret_far_imm+0x39/0x4f0 arch/x86/kvm/emulate.c:2270 x86_emulate_insn+0x1d81/0x5800 arch/x86/kvm/emulate.c:5289 x86_emulate_instruction+0x13c5/0x3090 arch/x86/kvm/x86.c:9101 kvm_mmu_page_fault+0x100a/0x1120 arch/x86/kvm/mmu/mmu.c:5778 handle_ept_violation+0x4ef/0x7e0 arch/x86/kvm/vmx/vmx.c:5788 __vmx_handle_exit arch/x86/kvm/vmx/vmx.c:6567 [inline] vmx_handle_exit+0x1b01/0x2130 arch/x86/kvm/vmx/vmx.c:6584 vcpu_enter_guest arch/x86/kvm/x86.c:10992 [inline] vcpu_run arch/x86/kvm/x86.c:11095 [inline] kvm_arch_vcpu_ioctl_run+0x9d4f/0xc680 arch/x86/kvm/x86.c:11321 kvm_vcpu_ioctl+0xbfc/0x1770 arch/x86/kvm/../../../virt/kvm/kvm_main.c:4155 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:871 [inline] __se_sys_ioctl+0x225/0x410 fs/ioctl.c:857 __x64_sys_ioctl+0x96/0xe0 fs/ioctl.c:857 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0x6d/0x140 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x63/0x6b Local variable eip created at: em_ret_far+0x3a/0x340 arch/x86/kvm/emulate.c:2243 em_ret_far_imm+0x39/0x4f0 arch/x86/kvm/emulate.c:2270 CPU: 0 PID: 5001 Comm: syz-executor428 Not tainted 6.7.0-syzkaller-00562-g9f8413c4a66f #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023 ===================================================== --- If you want syzbot to run the reproducer, reply with: #syz test: git://repo/address.git branch-or-commit-hash If you attach or paste a git patch, syzbot will apply it before testing.