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Wed, 25 Jan 2023 00:39:05 -0800 (PST) Date: Wed, 25 Jan 2023 00:38:49 -0800 In-Reply-To: <20230125083851.27759-1-surenb@google.com> Mime-Version: 1.0 References: <20230125083851.27759-1-surenb@google.com> X-Mailer: git-send-email 2.39.1.405.gd4c25cc71f-goog Message-ID: <20230125083851.27759-5-surenb@google.com> Subject: [PATCH v2 4/6] 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, 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, will@kernel.org, aneesh.kumar@linux.ibm.com, npiggin@gmail.com, chenhuacai@kernel.org, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, richard@nod.at, anton.ivanov@cambridgegreys.com, johannes@sipsolutions.net, qianweili@huawei.com, wangzhou1@hisilicon.com, herbert@gondor.apana.org.au, davem@davemloft.net, vkoul@kernel.org, airlied@gmail.com, daniel@ffwll.ch, maarten.lankhorst@linux.intel.com, mripard@kernel.org, tzimmermann@suse.de, l.stach@pengutronix.de, krzysztof.kozlowski@linaro.org, patrik.r.jakobsson@gmail.com, matthias.bgg@gmail.com, robdclark@gmail.com, quic_abhinavk@quicinc.com, dmitry.baryshkov@linaro.org, tomba@kernel.org, hjc@rock-chips.com, heiko@sntech.de, ray.huang@amd.com, kraxel@redhat.com, sre@kernel.org, mcoquelin.stm32@gmail.com, alexandre.torgue@foss.st.com, tfiga@chromium.org, m.szyprowski@samsung.com, mchehab@kernel.org, dimitri.sivanich@hpe.com, zhangfei.gao@linaro.org, jejb@linux.ibm.com, martin.petersen@oracle.com, dgilbert@interlog.com, hdegoede@redhat.com, mst@redhat.com, jasowang@redhat.com, alex.williamson@redhat.com, deller@gmx.de, jayalk@intworks.biz, viro@zeniv.linux.org.uk, nico@fluxnic.net, xiang@kernel.org, chao@kernel.org, tytso@mit.edu, adilger.kernel@dilger.ca, miklos@szeredi.hu, mike.kravetz@oracle.com, muchun.song@linux.dev, bhe@redhat.com, andrii@kernel.org, yoshfuji@linux-ipv6.org, dsahern@kernel.org, kuba@kernel.org, pabeni@redhat.com, perex@perex.cz, tiwai@suse.com, haojian.zhuang@gmail.com, robert.jarzmik@free.fr, linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, x86@kernel.org, linux-kernel@vger.kernel.org, linux-graphics-maintainer@vmware.com, linux-ia64@vger.kernel.org, linux-arch@vger.kernel.org, loongarch@lists.linux.dev, kvm@vger.kernel.org, linux-s390@vger.kernel.org, linux-sgx@vger.kernel.org, linux-um@lists.infradead.org, linux-acpi@vger.kernel.org, linux-crypto@vger.kernel.org, nvdimm@lists.linux.dev, dmaengine@vger.kernel.org, amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, etnaviv@lists.freedesktop.org, linux-samsung-soc@vger.kernel.org, intel-gfx@lists.freedesktop.org, linux-mediatek@lists.infradead.org, linux-arm-msm@vger.kernel.org, freedreno@lists.freedesktop.org, linux-rockchip@lists.infradead.org, linux-tegra@vger.kernel.org, virtualization@lists.linux-foundation.org, xen-devel@lists.xenproject.org, linux-stm32@st-md-mailman.stormreply.com, linux-rdma@vger.kernel.org, linux-media@vger.kernel.org, linux-accelerators@lists.ozlabs.org, sparclinux@vger.kernel.org, linux-scsi@vger.kernel.org, linux-staging@lists.linux.dev, target-devel@vger.kernel.org, linux-usb@vger.kernel.org, netdev@vger.kernel.org, linux-fbdev@vger.kernel.org, linux-aio@kvack.org, linux-fsdevel@vger.kernel.org, linux-erofs@lists.ozlabs.org, linux-ext4@vger.kernel.org, devel@lists.orangefs.org, kexec@lists.infradead.org, linux-xfs@vger.kernel.org, bpf@vger.kernel.org, linux-perf-users@vger.kernel.org, kasan-dev@googlegroups.com, selinux@vger.kernel.org, alsa-devel@alsa-project.org, kernel-team@android.com, surenb@google.com Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" 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 Acked-by: Michal Hocko Acked-by: Mike Rapoport (IBM) --- 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_h= v_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 =3D memslot->base_gfn; unsigned long end, start =3D gfn_to_hva(kvm, gfn); + unsigned long vm_flags; int ret =3D 0; struct vm_area_struct *vma; int merge_flag =3D (merge) ? MADV_MERGEABLE : MADV_UNMERGEABLE; @@ -409,12 +410,14 @@ static int kvmppc_memslot_page_merge(struct kvm *kvm, ret =3D H_STATE; break; } + vm_flags =3D vma->vm_flags; ret =3D ksm_madvise(vma, vma->vm_start, vma->vm_end, - merge_flag, &vma->vm_flags); + merge_flag, &vm_flags); if (ret) { ret =3D H_STATE; break; } + reset_vm_flags(vma, vm_flags); start =3D vma->vm_end; } while (end > vma->vm_end); =20 diff --git a/arch/s390/mm/gmap.c b/arch/s390/mm/gmap.c index 3a695b8a1e3c..d5eb47dcdacb 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 =3D current->mm; struct vm_area_struct *vma; + unsigned long vm_flags; int ret; VMA_ITERATOR(vmi, mm, 0); =20 for_each_vma(vmi, vma) { + vm_flags =3D vma->vm_flags; ret =3D 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 &=3D ~VM_MERGEABLE; return 0; diff --git a/mm/khugepaged.c b/mm/khugepaged.c index 8abc59345bf2..76b24cd0c179 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -354,6 +354,8 @@ struct attribute_group khugepaged_attr_group =3D { 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 =3D=3D &vma->vm_flags); switch (advice) { case MADV_HUGEPAGE: #ifdef CONFIG_S390 diff --git a/mm/ksm.c b/mm/ksm.c index 04f1c8c2df11..992b2be9f5e6 100644 --- a/mm/ksm.c +++ b/mm/ksm.c @@ -2573,6 +2573,8 @@ int ksm_madvise(struct vm_area_struct *vma, unsigned = long start, struct mm_struct *mm =3D vma->vm_mm; int err; =20 + /* vma->vm_flags can be changed only using modifier functions */ + BUG_ON(vm_flags =3D=3D &vma->vm_flags); switch (advice) { case MADV_MERGEABLE: /* --=20 2.39.1