From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-yb1-f202.google.com (mail-yb1-f202.google.com [209.85.219.202]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8806528F1 for ; Fri, 19 Jul 2024 17:30:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.219.202 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1721410254; cv=none; b=dbUJtljG/8tEknT5OPXP4Tcbj1QjBl0b83yK7pH3jDNClpkOxmOUd0XdN/oXvk2ntoFgcP0VTHIReBGX+EjzbhSSepd3xeFxpOTVFkWKYDnBMJ4e9VkrGrvu9Pdc4d4I2iIn20jeUAs8wjflajFQ/5pRIf2ORJSgLfiksVyJnqo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1721410254; c=relaxed/simple; bh=GMspW2YoqcOva052wx35RklyGV4RoHqvWFzeKJ1omDE=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=cO4GwAYzggNTjTIkbZSeP6x4kARMuoxWpdqDzwASIqZM60bL83qcXlh6nsacI3ryH9RZiSMfwXFQ4aFUo9i5BKJEg3YfRvqZZlw6/Q4P36UxN8hJ+iLoUZqM+sxVap7/YeLS7oP12WF0c8Vz8GkdrW5jC9JGgLCHTatCWiJqPIo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=TsXPnnJq; arc=none smtp.client-ip=209.85.219.202 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="TsXPnnJq" Received: by mail-yb1-f202.google.com with SMTP id 3f1490d57ef6-e05d5633db4so4900639276.3 for ; Fri, 19 Jul 2024 10:30:53 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1721410252; x=1722015052; darn=vger.kernel.org; h=content-transfer-encoding:cc:to:from:subject:message-id:references :mime-version:in-reply-to:date:from:to:cc:subject:date:message-id :reply-to; bh=gP6+VmSPHcYMxQS0JnsLJu5q9rtZVq5bNy3SOvLjfEg=; b=TsXPnnJqssPQQtvLTq+m6Rg0ZKhHaX5iojv7v0L3gQUFGumjZL5QBTAtDhzDoBnm06 RvJo+bJI06KWzj115NsGOVxAFGEXT3Y1X5owMus1xusaQLEdJ55MOmDHi7MFH+0heBsW x7lUnVi/ulfLA7haXlGCFPAFWzhZAR/svZgH6timYOddZPkhVC9KkORF2lZcSqcYCb6j 7dNZGzurgSFAFV7QpFxsLaVosW/9XkUWVVGmMFN1wvt61OcNsfIRzwZTkn3Msr5L1V7j owMYEUK20D+YuN3SiK95UesjbozJ8hszDn+nLKTg0m6PWS+pMOxL8ZwkFj0aM+Xr5Ns7 t3pQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1721410252; x=1722015052; h=content-transfer-encoding:cc:to:from:subject:message-id:references :mime-version:in-reply-to:date:x-gm-message-state:from:to:cc:subject :date:message-id:reply-to; bh=gP6+VmSPHcYMxQS0JnsLJu5q9rtZVq5bNy3SOvLjfEg=; b=eaxMBlhgweT4W7BzB2ObkuWLlIeakATg6Vwvt1AMD/RBmY3xV6KDV/JyIxna/hA5Sd amvb+LyZxOwTnzkhsuhM+sDOtDYpXOg0qIbQcCuvoEz2yq7BcKSaQj5ofDOaGkHow1Re pMg7EcTY3nvamD7mMXNeXv1igOKlHr/szX7cQX92z/pinizz+1e9d3Qg7VFDfzT3BfeO Wt1dXL/Kaac526wwpe/pvse5okmK4wk4kaUPALt9S59DDGRVfAUBKMj5RCvh2lXJpDY9 WBXjcah8BDZXhrvkNRbFf9Hrft5qo495mBEMVnD/DekUHdcq2py44J7RaZYrYVMVCym+ 7TEg== X-Forwarded-Encrypted: i=1; AJvYcCWkx0pDjqwvuTnsPDSMH/rM1aLNTVIckXK3cLWR4s2SpUBa89YgHqaGT6lBfhpwHqPzzUNzmOSeB9wxmIJiCAjrTk12f5yciQnKnqAw X-Gm-Message-State: AOJu0Yx3BUnmdDb/267X472gYt1AkU+b0lcYtNZgl3C5KldPWrQd4zcX S98nIKE2cwMXXR6eM5UTj8Uc1IL+urumtNfTNq9B6LRUcmvUJjU8n0fPNRPT//qpvjsr7nxpykx Rng== X-Google-Smtp-Source: AGHT+IF8y/u83nNvL3CbDE2OIMPQWlC17/lwUgB7FErVL+rh23Nj07seTNkwISxUuE1vxNR+9m/V/KKNbRc= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a05:6902:1891:b0:e03:2217:3c8f with SMTP id 3f1490d57ef6-e086fe4020amr908276.2.1721410252464; Fri, 19 Jul 2024 10:30:52 -0700 (PDT) Date: Fri, 19 Jul 2024 10:30:51 -0700 In-Reply-To: <7b47f4b7-eda8-40e2-883c-6d6c539a4649@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <7b47f4b7-eda8-40e2-883c-6d6c539a4649@gmail.com> Message-ID: Subject: Re: [BUG] 6.10 stable: =?utf-8?Q?arch=2Fx8?= =?utf-8?Q?6=2Fkvm=2Fxen=2Ec=3A1486=3A44=3A_error=3A_use_of_uninitialized_?= =?utf-8?B?dmFsdWUg4oCYcG9ydOKAmQ==?= [CWE-457] From: Sean Christopherson To: Mirsad Todorovac Cc: kvm@vger.kernel.org, Paolo Bonzini , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , linux-kernel@vger.kernel.org, Boris Ostrovsky Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable On Fri, Jul 19, 2024, Mirsad Todorovac wrote: > Hi, all, >=20 > While building stable tree version of 6.10, the following error occurred: >=20 > In line 1421 defines: >=20 > 1421 evtchn_port_t port, *ports; >=20 > The ports becomes &port in line 1470, but neither port nor *ports is assi= gned a value > until line 1486 where port is used: >=20 > 1485 if (sched_poll.nr_ports =3D=3D 1) > 1486 =E2=86=92 vcpu->arch.xen.poll_evtchn =3D port; >=20 > The visual inspection proves that the compiler is again right (GCC 12.3.0= ). Nope, the compiler is wrong. If sched_poll.nr_ports > 0, then kvm_read_gue= st_virt() will fill ports[sched_poll.nr_ports]. If kvm_read_guest_virt() fails to do= so, it will return an error and the above code will never be reached. if (kvm_read_guest_virt(vcpu, (gva_t)sched_poll.ports, ports, sched_poll.nr_ports * sizeof(*ports), &e)) { *r =3D -EFAULT; return true; }