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AJvYcCX9DA8yamHMhbgHR7PNW1hCjMGjQRrxnvH+GujevkCr22iMzNe+MGcSHhb60TUaQ14HhT3xUrlosA==@kvack.org X-Gm-Message-State: AOJu0YxK1evp/VO5JL389izd/UHQeGYd0NFV6UwlAd1ztt/IXnAjlBtY DU9zQDOcoWbLx1DzIywJgj4nej36qdhmp4jvAIp4An51zRjcIcR86Oq62CwvKSXTX+aXQz3JOS4 rd7dLXi7RghDaqq7N7uR2EfDpP7b4xDBV7Xh3 X-Gm-Gg: ASbGncviBgsLY4QHbiAKnuw7x44kwvzP5HTRZinEuit5x8nTVxx1hE7bTQRj9r07VQD I3/BTKwoMQW79sFr7FW3i+jSPt93+ATw2mkqbFw== X-Google-Smtp-Source: AGHT+IHZUqiUW2TdTijDnYW298vWshWfjCjNGwibZ85BeH2x4uiKxeyc0KowefHIQpDbMbw+3IhjXToAVqSqDQW5sv4= X-Received: by 2002:a05:622a:2c1:b0:460:491e:d2a2 with SMTP id d75a77b69052e-46c89dad5a8mr10535521cf.17.1736787781064; Mon, 13 Jan 2025 09:03:01 -0800 (PST) MIME-Version: 1.0 References: <20250111042604.3230628-1-surenb@google.com> <20250111042604.3230628-6-surenb@google.com> <5d46531b-570b-4f81-90f3-2fb157664f87@lucifer.local> In-Reply-To: <5d46531b-570b-4f81-90f3-2fb157664f87@lucifer.local> From: Suren Baghdasaryan Date: Mon, 13 Jan 2025 09:02:50 -0800 X-Gm-Features: AbW1kva24UmjIHnrtwbQDfckK6vVILPLXKlOEFQ433jaxF1GXtqbqRlIBqKlthI Message-ID: Subject: Re: [PATCH v9 05/17] mm: mark vmas detached upon exit To: Lorenzo Stoakes Cc: akpm@linux-foundation.org, peterz@infradead.org, willy@infradead.org, liam.howlett@oracle.com, david.laight.linux@gmail.com, mhocko@suse.com, vbabka@suse.cz, hannes@cmpxchg.org, mjguzik@gmail.com, oliver.sang@intel.com, mgorman@techsingularity.net, david@redhat.com, peterx@redhat.com, oleg@redhat.com, dave@stgolabs.net, paulmck@kernel.org, brauner@kernel.org, dhowells@redhat.com, hdanton@sina.com, hughd@google.com, lokeshgidra@google.com, minchan@google.com, jannh@google.com, shakeel.butt@linux.dev, souravpanda@google.com, pasha.tatashin@soleen.com, klarasmodin@gmail.com, richard.weiyang@gmail.com, corbet@lwn.net, linux-doc@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, kernel-team@android.com Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspamd-Queue-Id: 386FAA000F X-Stat-Signature: n5j7wstihnp9eg4pz9ffjy36cmzt3fz6 X-Rspam-User: X-Rspamd-Server: rspam09 X-HE-Tag: 1736787782-932143 X-HE-Meta: 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 gAhe5IuQ uaWA7zEUwQYO7SEpjDA1iGxOAeZxiSISf5t3MA8rwyhLbruB5vdwBZwczdC5kyh7sxdJ4hjqCJEtVNdJpjHGcL1q4uzPp+/P30v1FS0m/IEek5N+k36pAPOhEhkGXPYpxsayQE83KXCvipmkAscYq95BlFHKLee/J7WztwEVTyqNjWE/KdmTs6+67Qf1NqVq70A13Pzkv7IRBB6j0NlWf8iykUTJ7DkAXW4irdsNZTtrxGIRLCrpIDRx52hhKpgRGKa01Lg3WeA1ACwtADR2sSz0E1lQw+NylMwBF6WqYJBh0iZHrvJrtZCqIqg== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Mon, Jan 13, 2025 at 4:05=E2=80=AFAM Lorenzo Stoakes wrote: > > On Fri, Jan 10, 2025 at 08:25:52PM -0800, Suren Baghdasaryan wrote: > > When exit_mmap() removes vmas belonging to an exiting task, it does not > > mark them as detached since they can't be reached by other tasks and th= ey > > will be freed shortly. Once we introduce vma reuse, all vmas will have = to > > be in detached state before they are freed to ensure vma when reused is > > in a consistent state. Add missing vma_mark_detached() before freeing t= he > > vma. > > Hmm this really makes me worry that we'll see bugs from this detached > stuff, do we make this assumption anywhere else I wonder? This is the only place which does not currently detach the vma before freeing it. If someone tries adding a case like that in the future, they will be met with vma_assert_detached() inside vm_area_free(). > > > > > Signed-off-by: Suren Baghdasaryan > > Reviewed-by: Vlastimil Babka > > But regardless, prima facie, this looks fine, so: > > Reviewed-by: Lorenzo Stoakes > > > --- > > mm/vma.c | 6 ++++-- > > 1 file changed, 4 insertions(+), 2 deletions(-) > > > > diff --git a/mm/vma.c b/mm/vma.c > > index b9cf552e120c..93ff42ac2002 100644 > > --- a/mm/vma.c > > +++ b/mm/vma.c > > @@ -413,10 +413,12 @@ void remove_vma(struct vm_area_struct *vma, bool = unreachable) > > if (vma->vm_file) > > fput(vma->vm_file); > > mpol_put(vma_policy(vma)); > > - if (unreachable) > > + if (unreachable) { > > + vma_mark_detached(vma); > > __vm_area_free(vma); > > - else > > + } else { > > vm_area_free(vma); > > + } > > } > > > > /* > > -- > > 2.47.1.613.gc27f4b7a9f-goog > >