From patchwork Sun Mar 27 05:16:46 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Xiaomeng Tong X-Patchwork-Id: 554974 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 BD16BC433EF for ; Sun, 27 Mar 2022 05:17:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234679AbiC0FSf (ORCPT ); Sun, 27 Mar 2022 01:18:35 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51708 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234486AbiC0FSe (ORCPT ); Sun, 27 Mar 2022 01:18:34 -0400 Received: from mail-pl1-x629.google.com (mail-pl1-x629.google.com [IPv6:2607:f8b0:4864:20::629]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 46FCB13FB7; Sat, 26 Mar 2022 22:16:56 -0700 (PDT) Received: by mail-pl1-x629.google.com with SMTP id w8so12084648pll.10; Sat, 26 Mar 2022 22:16:56 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id; bh=v6BSL8VhVmwIej2fDS4fILub4T69woLAa8tFuzppLBk=; b=p1RRPdi5pT7hK/9+H4XP2JjJHVZf5LxJOg8oRMScYDqznggSSt6DW7OpAdLqP4W8AO QWWXECWxX9RPOiBmnLcGSoeUAuH1F+eyyngCzsyhHkZijHQoVL9KbaZwV9fGF305+GcJ KQ3lX6EwP13jR2+yq49xM5HsChFGhq36v/XvVksErbSWaX6jJWgE1FVl4GfE6ZGDp/ME zuCOEEjiXqpFYeQgPcQWuFdbX097X4/JPAM0o/UjSHybVTDj/5lDfa+2lsiPJUw6JxuM exi7XYluIPx9OcyFwBgAHJMqZ3Sg1+1ssX6ot4argKFyWxlQSjKuvG+YfQKY4uDl0/u6 BxRA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id; bh=v6BSL8VhVmwIej2fDS4fILub4T69woLAa8tFuzppLBk=; b=cU7Qp9vKXqvMRS73ELCec5O95MjonHDNhMdZGG1UhVf0l10wTWWe4P0Pr4VH9QF6aT XczTUSk1B4vSAvnA4sx6oKhUQX3P59WXyL4jjgpcedqI8navp+7juikgjP5YFm/jD01y q7yHwaWO09RzyDZSz8ej/tY8W9/1SZWjTedM3Az9ZqifgcLzRUP0897Xef3lTtmzl6Dz wAV0/rPyGbZiK1GZeDMhPFAqDqgFZ7tU8axmHG2LTr1vUqEK4lgd9NhaqulrIgxK4QS+ cmAvGs0hwGSUytdHYqLiraOfb/aNDR7hABQTomUlHB8f12lx9tRK4byBXkQ9D0g8gTmE MbRA== X-Gm-Message-State: AOAM532UQXTs3IBpjI+NwbcNoaBfZIlVLjMdeScS+2EVQNC7KrliRR1A XEUoTE7AyWTWYnHRegrTt28= X-Google-Smtp-Source: ABdhPJy4t0oQf/ADzsmcEEOjd/bCRxwrxMcaQ4ZDD2+D52Gbr5tPv/h47XDsREiddKHMcr1Fn6Xu5w== X-Received: by 2002:a17:902:b906:b0:14f:76a0:ad48 with SMTP id bf6-20020a170902b90600b0014f76a0ad48mr20445815plb.79.1648358215837; Sat, 26 Mar 2022 22:16:55 -0700 (PDT) Received: from localhost.localdomain ([115.220.243.108]) by smtp.googlemail.com with ESMTPSA id d11-20020a056a00198b00b004fa7da68465sm11290361pfl.60.2022.03.26.22.16.51 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 26 Mar 2022 22:16:55 -0700 (PDT) From: Xiaomeng Tong To: mpe@ellerman.id.au Cc: benh@kernel.crashing.org, paulus@samba.org, akpm@linux-foundation.org, liam.howlett@oracle.com, david@redhat.com, maz@kernel.org, Felix.Kuehling@amd.com, maciej.szmigiero@oracle.com, apopple@nvidia.com, bharata@linux.ibm.com, linuxram@us.ibm.com, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, Xiaomeng Tong , stable@vger.kernel.org Subject: [PATCH] kvm: fix incorrect NULL check on list iterator Date: Sun, 27 Mar 2022 13:16:46 +0800 Message-Id: <20220327051646.1856-1-xiam0nd.tong@gmail.com> X-Mailer: git-send-email 2.17.1 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org The bug is here: if (!p) return ret; The list iterator value 'p' will *always* be set and non-NULL by list_for_each_entry(), so it is incorrect to assume that the iterator value will be NULL if the list is empty or no element is found. To fix the bug, Use a new value 'iter' as the list iterator, while use the old value 'p' as a dedicated variable to point to the found element. Cc: stable@vger.kernel.org Fixes: dfaa973ae9605 ("KVM: PPC: Book3S HV: In H_SVM_INIT_DONE, migrate remaining normal-GFNs to secure-GFNs") Signed-off-by: Xiaomeng Tong --- arch/powerpc/kvm/book3s_hv_uvmem.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/arch/powerpc/kvm/book3s_hv_uvmem.c b/arch/powerpc/kvm/book3s_hv_uvmem.c index e414ca44839f..0cb20ee6a632 100644 --- a/arch/powerpc/kvm/book3s_hv_uvmem.c +++ b/arch/powerpc/kvm/book3s_hv_uvmem.c @@ -360,13 +360,15 @@ static bool kvmppc_gfn_is_uvmem_pfn(unsigned long gfn, struct kvm *kvm, static bool kvmppc_next_nontransitioned_gfn(const struct kvm_memory_slot *memslot, struct kvm *kvm, unsigned long *gfn) { - struct kvmppc_uvmem_slot *p; + struct kvmppc_uvmem_slot *p = NULL, *iter; bool ret = false; unsigned long i; - list_for_each_entry(p, &kvm->arch.uvmem_pfns, list) - if (*gfn >= p->base_pfn && *gfn < p->base_pfn + p->nr_pfns) + list_for_each_entry(iter, &kvm->arch.uvmem_pfns, list) + if (*gfn >= iter->base_pfn && *gfn < iter->base_pfn + iter->nr_pfns) { + p = iter; break; + } if (!p) return ret; /*