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AJvYcCXa69/yvvWlXbkm3UiQQBM8TbDLX6QSu6LbG4Ll0NYxZoEr2e8KkR/Jlr/FlCMbdBCfZfjILNxVtke7V2PbAbadPWAAbgvHABswmFWq X-Gm-Message-State: AOJu0Yw+NWbxvjiV7caxAOO+e/8HjcxwiuN8iVSkWNNHu8W/Pe7iQkDP z3gomGygJvcaVc9H+kYURqY+2L3xNPw2U6UEPfKbcuFMJqqdwpfBFLOu4WSe6Lu6Uz1xoayUlYh RfQ== X-Google-Smtp-Source: AGHT+IGRBUSegRKWvY9k/MUiR2zPJpvxmSAVwmL409Aq1G+pJ/bRUUEiomtWWOZYvhWEyQpKPyyiJsTtiU0= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a05:6a00:2d2a:b0:6e4:8fd5:e415 with SMTP id fa42-20020a056a002d2a00b006e48fd5e415mr41118pfb.6.1708524141325; Wed, 21 Feb 2024 06:02:21 -0800 (PST) Date: Wed, 21 Feb 2024 06:02:19 -0800 In-Reply-To: <000000000000bc78610611e4bba1@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <000000000000bc78610611e4bba1@google.com> Message-ID: Subject: Re: [syzbot] [kvm?] KMSAN: uninit-value in em_ret From: Sean Christopherson To: syzbot Cc: bp@alien8.de, dave.hansen@linux.intel.com, hpa@zytor.com, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, mingo@redhat.com, pbonzini@redhat.com, syzkaller-bugs@googlegroups.com, tglx@linutronix.de, x86@kernel.org Content-Type: text/plain; charset="us-ascii" On Wed, Feb 21, 2024, syzbot wrote: > Hello, > > syzbot found the following issue on: > > HEAD commit: b401b621758e Linux 6.8-rc5 > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=15cd41c2180000 > kernel config: https://syzkaller.appspot.com/x/.config?x=1b015d567058472 > dashboard link: https://syzkaller.appspot.com/bug?extid=ee5eb98a07d2c1fb30df > compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40 > > Unfortunately, I don't have any reproducer for this issue yet. > > Downloadable assets: > disk image: https://storage.googleapis.com/syzbot-assets/c32ff3cbe7ed/disk-b401b621.raw.xz > vmlinux: https://storage.googleapis.com/syzbot-assets/17621a870a21/vmlinux-b401b621.xz > kernel image: https://storage.googleapis.com/syzbot-assets/b06ad3ca55ee/bzImage-b401b621.xz > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+ee5eb98a07d2c1fb30df@syzkaller.appspotmail.com > > ===================================================== > BUG: KMSAN: uninit-value in assign_eip_near arch/x86/kvm/emulate.c:829 [inline] > BUG: KMSAN: uninit-value in em_ret+0x124/0x130 arch/x86/kvm/emulate.c:2238 > assign_eip_near arch/x86/kvm/emulate.c:829 [inline] > em_ret+0x124/0x130 arch/x86/kvm/emulate.c:2238 > x86_emulate_insn+0x1d87/0x5880 arch/x86/kvm/emulate.c:5292 > x86_emulate_instruction+0x13c9/0x30a0 arch/x86/kvm/x86.c:9171 > kvm_emulate_instruction arch/x86/kvm/x86.c:9251 [inline] > complete_emulated_io arch/x86/kvm/x86.c:11208 [inline] > complete_emulated_mmio+0x70b/0x8b0 arch/x86/kvm/x86.c:11268 > kvm_arch_vcpu_ioctl_run+0x1837/0xb890 arch/x86/kvm/x86.c:11380 > kvm_vcpu_ioctl+0xbfc/0x1770 arch/x86/kvm/../../../virt/kvm/kvm_main.c:4441 > 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+0xcf/0x1e0 arch/x86/entry/common.c:83 > entry_SYSCALL_64_after_hwframe+0x63/0x6b > > Local variable eip created at: > em_ret+0x37/0x130 arch/x86/kvm/emulate.c:2234 > x86_emulate_insn+0x1d87/0x5880 arch/x86/kvm/emulate.c:5292 > > CPU: 0 PID: 5793 Comm: syz-executor.0 Not tainted 6.8.0-rc5-syzkaller #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024 > ===================================================== #syz fix: KVM: x86: Clean up partially uninitialized integer in emulate_pop()