From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id EB2E743DEC7 for ; Fri, 9 Oct 2026 13:11:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791551498; cv=none; b=RuD4+uwhPSjjiiyK83kW+ksTbWPow2KeG4ce7rpFCHtpS15TP1rGEoptc+Lukqw++cO/RANm2g7/MaJotJNO4+jH1CFToCpYDrSmIVWgWvLqzyOqSR9WL4RnOqD148ym+15/woozbll3p6AYVfDNRFmlOizcGW2MadedWXgf14c= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791551498; c=relaxed/simple; bh=8WVvmUjTXoMbdyVBpGpz2Dtdzid6a0wSqsgzmGHqCk0=; h=Message-ID:From:Subject:To:Cc:In-Reply-To:References:Content-Type: Date; b=K4MATyPBGUEV8O6ht4T/SFBza49T9bjtznpEvZkVFjRpZCG4V03Nw5wUYehAchDjTydxvox8tH6NFTmOSnjuXAF9yiRBjEB7uXYWWQAUZ8OIw5WSX6NY4q4u81ciEUG94V1RzL7QDoG6MwJN7dgPIcgH4ZodIQYZfUQ/sYUHH34= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=VSOYlXPJ; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="VSOYlXPJ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9E3881F00898; Fri, 9 Oct 2026 13:11:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1791551497; bh=L6A9Ek0062NjmD6A2fBTXgz80sgVBRuk+Dc3DvO0meE=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=VSOYlXPJoYAcUujz8qy1Xqr+N9nuibxwf1NHNIYO16QaZYmzMRgP7m9WTGQDSGQd/ dPA9K+lveZSr893SEMZ7IYHvGFtLAfnv6bA6anDWWcNLZw+Pm9CIHmh1hkFe/2lEh0 5BcmRq/FNiRGvZCPyA0Jc0sZGTh9mKSlcCbvkFKPMOT9NOZC0V4OJfjO4SrqEFDd5e XYVS6Qhm2Cw3wpeQmPlKe0MwdwlfsUWul9tlLsyKD3tW896qZjnFcdr9u8zJJI06H1 Uxw+KFlpkv7SlI+7jJfpEM3yXs5cNjcgLvwnEmehnOcMyGLXFHe5Gnz8M3JebTzHqk JY+QXIRLDW+bg== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [PATCH v2 2/5] KVM: selftests: memstress: Add option to enable dirty-ring on VM creation Reply-To: sashiko-reviews@lists.linux.dev To: "Leonardo Bras" Cc: kvm@vger.kernel.org In-Reply-To: <20261009130054.3312154-4-leo.bras@arm.com> References: <20261009130054.3312154-2-leo.bras@arm.com> <20261009130054.3312154-4-leo.bras@arm.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Fri, 09 Oct 2026 13:11:37 +0000 Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Thank you for your contribution! Sashiko AI review found 1 potential issue(= s) to consider: - [High] kvm: selftests: missing KVM_MAX_VCPUS bounds check in memstress_vm= _create_with_vcpus() -- commit 8f8ed5a2bb5936b315dc077d1f97ad188346d5a2 Author: Leonardo Bras KVM: selftests: memstress: Add option to enable dirty-ring on VM creation This commit adds an option to memstress_create_vm() to take a dirty-ring si= ze and enables it before vCPU creation. It introduces a new function memstress_vm_create_with_vcpus() to handle this setup correctly. > diff --git a/tools/testing/selftests/kvm/lib/memstress.c b/tools/testing/= selftests/kvm/lib/memstress.c > index 880657df65e9e..b1f13499e85f4 100644 > --- a/tools/testing/selftests/kvm/lib/memstress.c > +++ b/tools/testing/selftests/kvm/lib/memstress.c > @@ -121,6 +121,27 @@ void memstress_setup_vcpus(struct kvm_vm *vm, int nr= _vcpus, [ ... ] > +static struct kvm_vm *memstress_vm_create_with_vcpus(struct memstress_pa= rams *params, > + u64 extra_mem_pages) > +{ > + struct kvm_vm *vm; > + int i; > + > + TEST_ASSERT(params->nr_vcpus > 0, "Invalid number of vCPUs (%d)", > + params->nr_vcpus); > + > + vm =3D __vm_create(VM_SHAPE(params->mode), params->nr_vcpus, extra_mem_= pages); > + > + if (params->dirty_ring_size) > + vm_enable_dirty_ring(vm, params->dirty_ring_size); > + > + for (i =3D 0; i < params->nr_vcpus; ++i) [Severity: High] Can this loop overflow the statically sized vcpus array? The vcpus array is bounded by KVM_MAX_VCPUS (512). When a user runs a memstress-based test with an argument greater than 512 on a host kernel whe= re KVM_CAP_MAX_VCPUS is greater than 512, or runs mmu_stress_test on a host wi= th more than ~682 physical cores, the option parser checks against KVM_CAP_MAX_VCPUS but not against KVM_MAX_VCPUS. Passing this unbounded params->nr_vcpus value to memstress_vm_create_with_vcpus() will blindly write past the end of the vcp= us array, causing memory corruption and crashing the selftest. > + vcpus[i] =3D vm_vcpu_add(vm, i, memstress_guest_code); > + > + kvm_arch_vm_finalize_vcpus(vm); > + return vm; > +} --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20261009130054.3312= 154-2-leo.bras@arm.com?part=3D2