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=-9.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, 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 53412C10F11 for ; Mon, 22 Apr 2019 19:59:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1FD08204EC for ; Mon, 22 Apr 2019 19:59:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1555963169; bh=kKSg9CKcEJ+JF+KJ8Z7C0kIhnyeUyt4CjM1tQIH4960=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=Gj7QWNLpMKHZjX/Z2FI5B/p/1l9PhDNg7nVunXoDlU0iTg3VIDrBYQ+uCFDKKJawz vwX+gV7VUKlUX8uVPxehZ9oW1ZRuOwy5tsC1KasKXnAl2XjvuKPOb4OTE/7S4SVBOf ykX0cssO1nYBzZHDFJgEgMSZ0qPnUMDk0Np0DFXY= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730345AbfDVTrn (ORCPT ); Mon, 22 Apr 2019 15:47:43 -0400 Received: from mail.kernel.org ([198.145.29.99]:50620 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730337AbfDVTrm (ORCPT ); Mon, 22 Apr 2019 15:47:42 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (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 93C1421902; Mon, 22 Apr 2019 19:47:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1555962461; bh=kKSg9CKcEJ+JF+KJ8Z7C0kIhnyeUyt4CjM1tQIH4960=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=O1/C1rA7KeOCQ/sK1g3TCnxxQzB80/ItoeytpcyxQ8FIu4tcsSx06LNfO6VAzYN2b WcjNLizmpYhTPzuy3twsCxRvcDH6+fDpC78aB9/8d1p6Ai61U4dhWPJnVBunGmN6Ml QVk1w3j2jIIfqJP2lFTB/lUiQX/Vrjyd+FpX8XdI= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Marc Zyngier , Sasha Levin , kvmarm@lists.cs.columbia.edu Subject: [PATCH AUTOSEL 4.14 09/43] KVM: arm/arm64: vgic-its: Take the srcu lock when parsing the memslots Date: Mon, 22 Apr 2019 15:46:53 -0400 Message-Id: <20190422194727.12495-9-sashal@kernel.org> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20190422194727.12495-1-sashal@kernel.org> References: <20190422194727.12495-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Marc Zyngier [ Upstream commit 7494cec6cb3ba7385a6a223b81906384f15aae34 ] Calling kvm_is_visible_gfn() implies that we're parsing the memslots, and doing this without the srcu lock is frown upon: [12704.164532] ============================= [12704.164544] WARNING: suspicious RCU usage [12704.164560] 5.1.0-rc1-00008-g600025238f51-dirty #16 Tainted: G W [12704.164573] ----------------------------- [12704.164589] ./include/linux/kvm_host.h:605 suspicious rcu_dereference_check() usage! [12704.164602] other info that might help us debug this: [12704.164616] rcu_scheduler_active = 2, debug_locks = 1 [12704.164631] 6 locks held by qemu-system-aar/13968: [12704.164644] #0: 000000007ebdae4f (&kvm->lock){+.+.}, at: vgic_its_set_attr+0x244/0x3a0 [12704.164691] #1: 000000007d751022 (&its->its_lock){+.+.}, at: vgic_its_set_attr+0x250/0x3a0 [12704.164726] #2: 00000000219d2706 (&vcpu->mutex){+.+.}, at: lock_all_vcpus+0x64/0xd0 [12704.164761] #3: 00000000a760aecd (&vcpu->mutex){+.+.}, at: lock_all_vcpus+0x64/0xd0 [12704.164794] #4: 000000000ef8e31d (&vcpu->mutex){+.+.}, at: lock_all_vcpus+0x64/0xd0 [12704.164827] #5: 000000007a872093 (&vcpu->mutex){+.+.}, at: lock_all_vcpus+0x64/0xd0 [12704.164861] stack backtrace: [12704.164878] CPU: 2 PID: 13968 Comm: qemu-system-aar Tainted: G W 5.1.0-rc1-00008-g600025238f51-dirty #16 [12704.164887] Hardware name: rockchip evb_rk3399/evb_rk3399, BIOS 2019.04-rc3-00124-g2feec69fb1 03/15/2019 [12704.164896] Call trace: [12704.164910] dump_backtrace+0x0/0x138 [12704.164920] show_stack+0x24/0x30 [12704.164934] dump_stack+0xbc/0x104 [12704.164946] lockdep_rcu_suspicious+0xcc/0x110 [12704.164958] gfn_to_memslot+0x174/0x190 [12704.164969] kvm_is_visible_gfn+0x28/0x70 [12704.164980] vgic_its_check_id.isra.0+0xec/0x1e8 [12704.164991] vgic_its_save_tables_v0+0x1ac/0x330 [12704.165001] vgic_its_set_attr+0x298/0x3a0 [12704.165012] kvm_device_ioctl_attr+0x9c/0xd8 [12704.165022] kvm_device_ioctl+0x8c/0xf8 [12704.165035] do_vfs_ioctl+0xc8/0x960 [12704.165045] ksys_ioctl+0x8c/0xa0 [12704.165055] __arm64_sys_ioctl+0x28/0x38 [12704.165067] el0_svc_common+0xd8/0x138 [12704.165078] el0_svc_handler+0x38/0x78 [12704.165089] el0_svc+0x8/0xc Make sure the lock is taken when doing this. Fixes: bf308242ab98 ("KVM: arm/arm64: VGIC/ITS: protect kvm_read_guest() calls with SRCU lock") Reviewed-by: Eric Auger Signed-off-by: Marc Zyngier Signed-off-by: Sasha Levin (Microsoft) --- virt/kvm/arm/vgic/vgic-its.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c index d72b8481f250..dc06f5e40041 100644 --- a/virt/kvm/arm/vgic/vgic-its.c +++ b/virt/kvm/arm/vgic/vgic-its.c @@ -704,8 +704,9 @@ static bool vgic_its_check_id(struct vgic_its *its, u64 baser, u32 id, int l1_tbl_size = GITS_BASER_NR_PAGES(baser) * SZ_64K; u64 indirect_ptr, type = GITS_BASER_TYPE(baser); int esz = GITS_BASER_ENTRY_SIZE(baser); - int index; + int index, idx; gfn_t gfn; + bool ret; switch (type) { case GITS_BASER_TYPE_DEVICE: @@ -732,7 +733,8 @@ static bool vgic_its_check_id(struct vgic_its *its, u64 baser, u32 id, if (eaddr) *eaddr = addr; - return kvm_is_visible_gfn(its->dev->kvm, gfn); + + goto out; } /* calculate and check the index into the 1st level */ @@ -766,7 +768,12 @@ static bool vgic_its_check_id(struct vgic_its *its, u64 baser, u32 id, if (eaddr) *eaddr = indirect_ptr; - return kvm_is_visible_gfn(its->dev->kvm, gfn); + +out: + idx = srcu_read_lock(&its->dev->kvm->srcu); + ret = kvm_is_visible_gfn(its->dev->kvm, gfn); + srcu_read_unlock(&its->dev->kvm->srcu, idx); + return ret; } static int vgic_its_alloc_collection(struct vgic_its *its, -- 2.19.1