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 AC701C54EBD for ; Mon, 9 Jan 2023 20:55:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237620AbjAIUzp (ORCPT ); Mon, 9 Jan 2023 15:55:45 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34634 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237607AbjAIUzV (ORCPT ); Mon, 9 Jan 2023 15:55:21 -0500 Received: from mail-yw1-x1149.google.com (mail-yw1-x1149.google.com [IPv6:2607:f8b0:4864:20::1149]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D3F548110C for ; Mon, 9 Jan 2023 12:54:22 -0800 (PST) Received: by mail-yw1-x1149.google.com with SMTP id 00721157ae682-4c57d19de6fso76641347b3.20 for ; Mon, 09 Jan 2023 12:54:22 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=N7mRvZOR9OSs0kq6Wz0vbjqUGqop/n2M19/OmQJBzkI=; b=kK6VGqQrZF8SG+/SjIkBNYvs6AD0XP75PAW8W4oCooA8s3XRGaAuXa1jS1HIr83jUq PfI+R4O3x61YrRtYzJolldiJm8hvHC8SxT9psAXnN9HRUclq2Ip2r4U5z9IkvWwPkq1G R8EmUXB5Ci5VhDTGcvMKuR9ocC5TZKh6cUC/3KU3F2jjjEENLe5/WyQt1N1DazjgpxS4 yljAKeS+kCfpqMArc2lBS+96rZHSjRTZ1IN5B+phw/v3GaAeI+j/XkkH3A++TUlQdWQv Z4M4yuHxGDrl8gjpdpiZsATGjMq3MZe3RurXo4cwDj7NtnBXJ6X3cbtci2E7Lsi2JjQl 1UiQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=N7mRvZOR9OSs0kq6Wz0vbjqUGqop/n2M19/OmQJBzkI=; b=nEUCk+pyS4koPMNY1PZXCXyvazvvcyQOBTpIsqcv7/RMfnTcMRK9Otz5NeVqLOB1+V Puv80WK1xq40Cqo4TU8JcUx7f5plvoY0cp6IZhxppv6YJxhlRokLqzqlDyh1kSnCZ/Ld QZGYTEiyjEkfMkSNuUvMIMgP0OWZPPJw2in9Iz5Co1uAuFV1ziAVXVBvCPnLSooZeEFZ u0Ta2uhz3zY6gd1+5jPSFec32amrktg0hd9KeecY8kSoR9g7Ah51ALP3+ZPmqsJwkueq pntl+3B9P0Z3lpuG3j/TkWDpBZjH4r+rWeZJwDuXhWE3FdI0Bp+puDmvSfguMzec7Nrp nOdA== X-Gm-Message-State: AFqh2kpnoUkXo9ITcQuUFFryBUSYLFrd5CVqH1Cj1WEyK6sg2eTqndBM 9q3NijcrR0CMLOb4S6aTrdnpoIP8q+o= X-Google-Smtp-Source: AMrXdXshiyJrN6EY9CYZGhpA9uWntRCGsbXmXt4bSfqvBPsR2AoGwmZNzha8yCXqkiCEpIRfWXrumcAFYxY= X-Received: from surenb-desktop.mtv.corp.google.com ([2620:15c:211:200:9393:6f7a:d410:55ca]) (user=surenb job=sendgmr) by 2002:a81:65d7:0:b0:39a:afeb:f519 with SMTP id z206-20020a8165d7000000b0039aafebf519mr799450ywb.146.1673297662050; Mon, 09 Jan 2023 12:54:22 -0800 (PST) Date: Mon, 9 Jan 2023 12:53:11 -0800 In-Reply-To: <20230109205336.3665937-1-surenb@google.com> Mime-Version: 1.0 References: <20230109205336.3665937-1-surenb@google.com> X-Mailer: git-send-email 2.39.0.314.g84b9a713c41-goog Message-ID: <20230109205336.3665937-17-surenb@google.com> Subject: [PATCH 16/41] mm: replace vma->vm_flags indirect modification in ksm_madvise From: Suren Baghdasaryan To: akpm@linux-foundation.org Cc: michel@lespinasse.org, jglisse@google.com, mhocko@suse.com, vbabka@suse.cz, hannes@cmpxchg.org, mgorman@techsingularity.net, dave@stgolabs.net, willy@infradead.org, liam.howlett@oracle.com, peterz@infradead.org, ldufour@linux.ibm.com, laurent.dufour@fr.ibm.com, paulmck@kernel.org, luto@kernel.org, songliubraving@fb.com, peterx@redhat.com, david@redhat.com, dhowells@redhat.com, hughd@google.com, bigeasy@linutronix.de, kent.overstreet@linux.dev, punit.agrawal@bytedance.com, lstoakes@gmail.com, peterjung1337@gmail.com, rientjes@google.com, axelrasmussen@google.com, joelaf@google.com, minchan@google.com, jannh@google.com, shakeelb@google.com, tatashin@google.com, edumazet@google.com, gthelen@google.com, gurua@google.com, arjunroy@google.com, soheil@google.com, hughlynch@google.com, leewalsh@google.com, posk@google.com, linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, x86@kernel.org, linux-kernel@vger.kernel.org, kernel-team@android.com, surenb@google.com Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Replace indirect modifications to vma->vm_flags with calls to modifier functions to be able to track flag changes and to keep vma locking correctness. Add a BUG_ON check in ksm_madvise() to catch indirect vm_flags modification attempts. Signed-off-by: Suren Baghdasaryan --- arch/powerpc/kvm/book3s_hv_uvmem.c | 5 ++++- arch/s390/mm/gmap.c | 5 ++++- mm/khugepaged.c | 2 ++ mm/ksm.c | 2 ++ 4 files changed, 12 insertions(+), 2 deletions(-) diff --git a/arch/powerpc/kvm/book3s_hv_uvmem.c b/arch/powerpc/kvm/book3s_hv_uvmem.c index 1d67baa5557a..325a7a47d348 100644 --- a/arch/powerpc/kvm/book3s_hv_uvmem.c +++ b/arch/powerpc/kvm/book3s_hv_uvmem.c @@ -393,6 +393,7 @@ static int kvmppc_memslot_page_merge(struct kvm *kvm, { unsigned long gfn = memslot->base_gfn; unsigned long end, start = gfn_to_hva(kvm, gfn); + unsigned long vm_flags; int ret = 0; struct vm_area_struct *vma; int merge_flag = (merge) ? MADV_MERGEABLE : MADV_UNMERGEABLE; @@ -409,12 +410,14 @@ static int kvmppc_memslot_page_merge(struct kvm *kvm, ret = H_STATE; break; } + vm_flags = vma->vm_flags; ret = ksm_madvise(vma, vma->vm_start, vma->vm_end, - merge_flag, &vma->vm_flags); + merge_flag, &vm_flags); if (ret) { ret = H_STATE; break; } + reset_vm_flags(vma, vm_flags); start = vma->vm_end; } while (end > vma->vm_end); diff --git a/arch/s390/mm/gmap.c b/arch/s390/mm/gmap.c index 3811d6c86d09..e47387f8be6d 100644 --- a/arch/s390/mm/gmap.c +++ b/arch/s390/mm/gmap.c @@ -2587,14 +2587,17 @@ int gmap_mark_unmergeable(void) { struct mm_struct *mm = current->mm; struct vm_area_struct *vma; + unsigned long vm_flags; int ret; VMA_ITERATOR(vmi, mm, 0); for_each_vma(vmi, vma) { + vm_flags = vma->vm_flags; ret = ksm_madvise(vma, vma->vm_start, vma->vm_end, - MADV_UNMERGEABLE, &vma->vm_flags); + MADV_UNMERGEABLE, &vm_flags); if (ret) return ret; + reset_vm_flags(vma, vm_flags); } mm->def_flags &= ~VM_MERGEABLE; return 0; diff --git a/mm/khugepaged.c b/mm/khugepaged.c index 5cb401aa2b9d..5376246a3052 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -352,6 +352,8 @@ struct attribute_group khugepaged_attr_group = { int hugepage_madvise(struct vm_area_struct *vma, unsigned long *vm_flags, int advice) { + /* vma->vm_flags can be changed only using modifier functions */ + BUG_ON(vm_flags == &vma->vm_flags); switch (advice) { case MADV_HUGEPAGE: #ifdef CONFIG_S390 diff --git a/mm/ksm.c b/mm/ksm.c index dd02780c387f..d05c41b289db 100644 --- a/mm/ksm.c +++ b/mm/ksm.c @@ -2471,6 +2471,8 @@ int ksm_madvise(struct vm_area_struct *vma, unsigned long start, struct mm_struct *mm = vma->vm_mm; int err; + /* vma->vm_flags can be changed only using modifier functions */ + BUG_ON(vm_flags == &vma->vm_flags); switch (advice) { case MADV_MERGEABLE: /* -- 2.39.0