From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 971B0C433F5 for ; Mon, 17 Jan 2022 16:59:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241272AbiAQQ7s (ORCPT ); Mon, 17 Jan 2022 11:59:48 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44586 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241290AbiAQQ7d (ORCPT ); Mon, 17 Jan 2022 11:59:33 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B002DC061401; Mon, 17 Jan 2022 08:59:32 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 2603AB81131; Mon, 17 Jan 2022 16:59:31 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id CFB72C36AE3; Mon, 17 Jan 2022 16:59:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1642438770; bh=e9qHwmWQeW+I8N/3hk78hKYr7tPj2scOY6Gr/oCbo4I=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=buw1cRN7a4U9Em28n5QbtNPjk6yaYLUhL9eh6Vp2zsjdZOvzQqO8NjZ9YrFuixvD1 MbCcLR8slQs9wk1dfZuTw6eCplb9LHRmCTElkSe764qTuGGpF/ziOzTOwS54RWjmSf e0LzeDp4DI/7ENZuGAALlGaM00LfRX6U8ed3bOXf8QeeGn/buEM7RlHsODSW/7OOqG KQqMWEZ495mD9NHo0MLfL90uQMtV+dEolKUYwclIkb2HkuT9R3rUGx/i3/SjnK4JdH yGCxUL/dSy0dTfvi5duLykTWg76PhVeUrIRgd1FOOBVKHyrkD2JV+J5V4VWztmQc5i /EAFjpUffCfSQ== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Alexey Kardashevskiy , Fabiano Rosas , Michael Ellerman , Sasha Levin , npiggin@gmail.com, paulus@ozlabs.org, ravi.bangoria@linux.ibm.com, bharata@linux.ibm.com, nathan@kernel.org, linuxppc-dev@lists.ozlabs.org Subject: [PATCH AUTOSEL 5.16 15/52] KVM: PPC: Book3S: Suppress failed alloc warning in H_COPY_TOFROM_GUEST Date: Mon, 17 Jan 2022 11:58:16 -0500 Message-Id: <20220117165853.1470420-15-sashal@kernel.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220117165853.1470420-1-sashal@kernel.org> References: <20220117165853.1470420-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Alexey Kardashevskiy [ Upstream commit 792020907b11c6f9246c21977cab3bad985ae4b6 ] H_COPY_TOFROM_GUEST is an hcall for an upper level VM to access its nested VMs memory. The userspace can trigger WARN_ON_ONCE(!(gfp & __GFP_NOWARN)) in __alloc_pages() by constructing a tiny VM which only does H_COPY_TOFROM_GUEST with a too big GPR9 (number of bytes to copy). This silences the warning by adding __GFP_NOWARN. Spotted by syzkaller. Signed-off-by: Alexey Kardashevskiy Reviewed-by: Fabiano Rosas Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20210901084550.1658699-1-aik@ozlabs.ru Signed-off-by: Sasha Levin --- arch/powerpc/kvm/book3s_hv_nested.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/powerpc/kvm/book3s_hv_nested.c b/arch/powerpc/kvm/book3s_hv_nested.c index ed8a2c9f56299..89295b52a97c3 100644 --- a/arch/powerpc/kvm/book3s_hv_nested.c +++ b/arch/powerpc/kvm/book3s_hv_nested.c @@ -582,7 +582,7 @@ long kvmhv_copy_tofrom_guest_nested(struct kvm_vcpu *vcpu) if (eaddr & (0xFFFUL << 52)) return H_PARAMETER; - buf = kzalloc(n, GFP_KERNEL); + buf = kzalloc(n, GFP_KERNEL | __GFP_NOWARN); if (!buf) return H_NO_MEM; -- 2.34.1