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 X-Spam-Level: X-Spam-Status: No, score=-14.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 90E35C433DF for ; Mon, 24 Aug 2020 11:29:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5F66A2074D for ; Mon, 24 Aug 2020 11:29:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1598268562; bh=NYiwj+2Xby3LHMGCk1joilOc35OND3SJCoRZ5v2O4ho=; h=From:To:Cc:Subject:Date:List-ID:From; b=kVIpJgGG/sdbf04KtRjly8YqSIV0lNPTCQXYjEibkdy5Uz7bYseuyCWiHeUNg47s5 FPK4YS+eSTYpB2leRfheUnGRRoGgOGXucTIhJcMCG1Togf4apQqcI0odrxdwzozrMW 4HOCJO/GqvuahOsN30iSkg7knRQ69MxOHrZML7HY= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726690AbgHXL3T (ORCPT ); Mon, 24 Aug 2020 07:29:19 -0400 Received: from mail.kernel.org ([198.145.29.99]:38918 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726863AbgHXL3E (ORCPT ); Mon, 24 Aug 2020 07:29:04 -0400 Received: from localhost.localdomain (236.31.169.217.in-addr.arpa [217.169.31.236]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 98E1B2074D; Mon, 24 Aug 2020 11:28:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1598268540; bh=NYiwj+2Xby3LHMGCk1joilOc35OND3SJCoRZ5v2O4ho=; h=From:To:Cc:Subject:Date:From; b=BJTBpmHdnlW+qaqYVqPtom/sjAATJrACtYHEXriX5yxrKSvR3wb7J4olSa9V0uTtP Qm99tVniFcVRhnhIomjjiIA8QbCYoyQbmRpz1ShUaodlmH7jjB7WoHMD/7radwmSiX o5Cgg2z6rYKA8X6sAP9YmegCOfAMUlwWxmWRLfdI= From: Will Deacon To: gregkh@linuxfoundation.org Cc: linux-kernel@vger.kernel.org, maz@kernel.org, suzuki.poulose@arm.com, james.morse@arm.com, pbonzini@redhat.com, kernel-team@android.com, Will Deacon , stable@vger.kernel.org Subject: [PATCH stable-4.4.y backport] KVM: arm/arm64: Don't reschedule in unmap_stage2_range() Date: Mon, 24 Aug 2020 12:28:54 +0100 Message-Id: <20200824112854.24651-1-will@kernel.org> X-Mailer: git-send-email 2.20.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Upstream commits fdfe7cbd5880 ("KVM: Pass MMU notifier range flags to kvm_unmap_hva_range()") and b5331379bc62 ("KVM: arm64: Only reschedule if MMU_NOTIFIER_RANGE_BLOCKABLE is not set") fix a "sleeping from invalid context" BUG caused by unmap_stage2_range() attempting to reschedule when called on the OOM path. Unfortunately, these patches rely on the MMU notifier callback being passed knowledge about whether or not blocking is permitted, which was introduced in 4.19. Rather than backport this considerable amount of infrastructure just for KVM on arm, instead just remove the conditional reschedule. Cc: # v4.4 only Cc: Marc Zyngier Cc: Suzuki K Poulose Cc: James Morse Signed-off-by: Will Deacon --- arch/arm/kvm/mmu.c | 8 -------- 1 file changed, 8 deletions(-) diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c index e0267532bd4e..edd392fdc14b 100644 --- a/arch/arm/kvm/mmu.c +++ b/arch/arm/kvm/mmu.c @@ -300,14 +300,6 @@ static void unmap_range(struct kvm *kvm, pgd_t *pgdp, next = kvm_pgd_addr_end(addr, end); if (!pgd_none(*pgd)) unmap_puds(kvm, pgd, addr, next); - /* - * If we are dealing with a large range in - * stage2 table, release the kvm->mmu_lock - * to prevent starvation and lockup detector - * warnings. - */ - if (kvm && (next != end)) - cond_resched_lock(&kvm->mmu_lock); } while (pgd++, addr = next, addr != end); } -- 2.28.0.297.g1956fa8f8d-goog