From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wr1-f73.google.com (mail-wr1-f73.google.com [209.85.221.73]) (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 7D85A364EBC for ; Wed, 4 Mar 2026 16:22:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.221.73 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772641350; cv=none; b=QpRUooUvIAAYdWTcK/GPoNP8fOCOE2LRpq0OKhSVHU3IoZUJu6QYQNsOwOW8Ry8vZSPZ37SNApdejIGI4Ys1Lqnu3s/OhSuFkAtkUbox55GXMvGUpDNYABfe7ooB7VGn/XXv3GGlHyHYlku4AuSqfXx1HTtvQC6Duh7lnkYYwlU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772641350; c=relaxed/simple; bh=/xgapYGhd/TA/B5MXAVB3XXtgz3ZRTvK/g/SPJvQHAY=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=Mqq338Ghf/KzBTiRlKe6gwZsblCFRP2N5zfAlzNhPmvuHQVK4cUtRaznthi5OonaHSm/XlqJIxkcyFstUUJAw1FXzAxxdu3CfkWiJTUwGFRo3PL1qQ7iR9oD3d2eyhw/lnqtuimA3OuHfra37FrdDQce39cLwXiKUv9CjMLtQJc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--tabba.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=WxNmafIt; arc=none smtp.client-ip=209.85.221.73 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--tabba.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="WxNmafIt" Received: by mail-wr1-f73.google.com with SMTP id ffacd0b85a97d-439c5f65688so913536f8f.1 for ; Wed, 04 Mar 2026 08:22:26 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1772641345; x=1773246145; darn=lists.linux.dev; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=0oCJqMFMJBFzo1B9Dat2jPTYOPY6jcDnrEpSARx0ibE=; b=WxNmafItn/Q5eN8/GZ51FV8lQYcFoyraNIaXnd8Bsa4r2cdBo5m6hjckWmA36bgzQ9 IRFlJdWInswtfXN0yjvwC939jPZhx74l018cFS1eeEfz4K8fJ/D+uEFiQwwBf80pfsfD qWOw+Gv2RBiLZOY0B4ThVRIv+q7n6DwLex/itLhnylIYZqzgOsTteLYs25bgJ14H5fEP 7Tbc/eNQAMUbXeimpNUU3B8U3PaYmMKI7zrIyKrY/9aiP9jnh+PH2KPZyzG4ysPCS/CO kglBiRwou9fCuWq8vk0peEm+xqsTOtQ/OAgtbjyFnfTQqSrLu1kUIyri5h078eSUg6JE Y6PA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1772641345; x=1773246145; h=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=0oCJqMFMJBFzo1B9Dat2jPTYOPY6jcDnrEpSARx0ibE=; b=nldqFSJLk/cJPvSXKZX3rcYPRU/smWUzsqLimlgTrWAoMj3vfymLu+WtTTuYo/gSy9 k2+HADsArg0pwGhBZ2Hr4YfxNIXxNeBCs5l57V57FD6qx8SYY5RKlQH6Mgn/PF69vpuC G796NBild0XxY+y1VNAAN2MpuF07HAWGWaihig/7uJOxJTG52KAfv6LnKlSzyjNNJtQS xiAIczWUrO0AnnaS/2VMY+e7j/qIrQuhwq2/WLGfPSmx4LLNeXRyuUXKRkFJRNTuc0Qj /wYlBQuS49+WeSvAaVkvvAYDYubY4IPCeGYjMs7Rwz0QbznQ/8J+ALtnInyYPl2N2gJC 6VXA== X-Forwarded-Encrypted: i=1; AJvYcCWRonY6SgW8+90FZ4GsK3hbpuRovRrBlqKOFJJgjWmsZQ1nbAtve0wlkALssYtqPUvg1d5mzu4=@lists.linux.dev X-Gm-Message-State: AOJu0Yycw6Mr5n2P97HB/BaCyRNcok1zcH8DTTmXiqjlr/H4A9aIjvej ZIFZplhry+PRpM/YXm1xaPEuF7cWSylpuV9zLKSC3CQM41tc4A5KoaFpH/u0oBw/980tpfOwt34 SDw== X-Received: from wrid6.prod.google.com ([2002:a05:6000:1866:b0:439:cc48:d5]) (user=tabba job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6000:1acf:b0:439:b3ff:9ab9 with SMTP id ffacd0b85a97d-439c7ffcb29mr5321494f8f.48.1772641344607; Wed, 04 Mar 2026 08:22:24 -0800 (PST) Date: Wed, 4 Mar 2026 16:22:21 +0000 In-Reply-To: <20260304162222.836152-1-tabba@google.com> Precedence: bulk X-Mailing-List: kvmarm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260304162222.836152-1-tabba@google.com> X-Mailer: git-send-email 2.53.0.473.g4a7958ca14-goog Message-ID: <20260304162222.836152-2-tabba@google.com> Subject: [PATCH v1 1/2] KVM: arm64: Fix page leak in user_mem_abort() on atomic fault From: Fuad Tabba To: kvm@vger.kernel.org, kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org Cc: maz@kernel.org, oliver.upton@linux.dev, joey.gouly@arm.com, suzuki.poulose@arm.com, yuzenghui@huawei.com, catalin.marinas@arm.com, will@kernel.org, yangyicong@hisilicon.com, wangzhou1@hisilicon.com, tabba@google.com Content-Type: text/plain; charset="UTF-8" When a guest performs an atomic/exclusive operation on memory lacking the required attributes, user_mem_abort() injects a data abort and returns early. However, it fails to release the reference to the host page acquired via __kvm_faultin_pfn(). A malicious guest could repeatedly trigger this fault, leaking host page references and eventually causing host memory exhaustion (OOM). Fix this by consolidating the early error returns to a new out_put_page label that correctly calls kvm_release_page_unused(). Fixes: 2937aeec9dc5 ("KVM: arm64: Handle DABT caused by LS64* instructions on unsupported memory") Signed-off-by: Fuad Tabba --- arch/arm64/kvm/mmu.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c index ec2eee857208..e1d6a4f591a9 100644 --- a/arch/arm64/kvm/mmu.c +++ b/arch/arm64/kvm/mmu.c @@ -1837,10 +1837,8 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, if (exec_fault && s2_force_noncacheable) ret = -ENOEXEC; - if (ret) { - kvm_release_page_unused(page); - return ret; - } + if (ret) + goto out_put_page; /* * Guest performs atomic/exclusive operations on memory with unsupported @@ -1850,7 +1848,8 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, */ if (esr_fsc_is_excl_atomic_fault(kvm_vcpu_get_esr(vcpu))) { kvm_inject_dabt_excl_atomic(vcpu, kvm_vcpu_get_hfar(vcpu)); - return 1; + ret = 1; + goto out_put_page; } if (nested) @@ -1936,6 +1935,10 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, mark_page_dirty_in_slot(kvm, memslot, gfn); return ret != -EAGAIN ? ret : 0; + +out_put_page: + kvm_release_page_unused(page); + return ret; } /* Resolve the access fault by making the page young again. */ -- 2.53.0.473.g4a7958ca14-goog