From patchwork Mon Jan 24 18:42:32 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 535039 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 AE3CCC43219 for ; Mon, 24 Jan 2022 23:54:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2365620AbiAXXvX (ORCPT ); Mon, 24 Jan 2022 18:51:23 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33234 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1578585AbiAXWDK (ORCPT ); Mon, 24 Jan 2022 17:03:10 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A3B63C036BDD; Mon, 24 Jan 2022 12:41:36 -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 dfw.source.kernel.org (Postfix) with ESMTPS id 40CDD615A0; Mon, 24 Jan 2022 20:41:36 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 228A5C340E5; Mon, 24 Jan 2022 20:41:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1643056895; bh=e9qHwmWQeW+I8N/3hk78hKYr7tPj2scOY6Gr/oCbo4I=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=FdWbgKA6PNoQWcYKYBUYP1zREWMCZr/0xS+Rn9cfo4wRsxmpQ52XmKt9r3O/aa2dS w0KxgDuuS80QrjpajX5+l16OaJZQRIn3LjC51kcgj+jdCUYh4XKwWPhJAj9NXEgSvq fTTk3kAGIOTtTH/T6OfniVWsprHApqU50PD9jj/Y= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Alexey Kardashevskiy , Fabiano Rosas , Michael Ellerman , Sasha Levin Subject: [PATCH 5.15 635/846] KVM: PPC: Book3S: Suppress failed alloc warning in H_COPY_TOFROM_GUEST Date: Mon, 24 Jan 2022 19:42:32 +0100 Message-Id: <20220124184122.929031010@linuxfoundation.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220124184100.867127425@linuxfoundation.org> References: <20220124184100.867127425@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@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;