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Wed, 15 Feb 2023 21:18:35 -0800 (PST) Date: Wed, 15 Feb 2023 21:17:32 -0800 In-Reply-To: <20230216051750.3125598-1-surenb@google.com> Mime-Version: 1.0 References: <20230216051750.3125598-1-surenb@google.com> X-Mailer: git-send-email 2.39.1.581.gbfd45094c4-goog Message-ID: <20230216051750.3125598-18-surenb@google.com> Subject: [PATCH v3 17/35] mm/mmap: write-lock VMA before shrinking or expanding it 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, mingo@redhat.com, will@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, chriscli@google.com, axelrasmussen@google.com, joelaf@google.com, minchan@google.com, rppt@kernel.org, jannh@google.com, shakeelb@google.com, tatashin@google.com, edumazet@google.com, gthelen@google.com, gurua@google.com, arjunroy@google.com, soheil@google.com, leewalsh@google.com, posk@google.com, michalechner92@googlemail.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, Suren Baghdasaryan X-Rspam-User: X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: A36C780006 X-Stat-Signature: y7x1scagruxp7ck8n4g48br8i957xx81 X-HE-Tag: 1676524716-734210 X-HE-Meta: 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 6u8bFhbD 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 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: vma_expand and vma_shrink change VMA boundaries. Expansion might also result in freeing of an adjacent VMA. Write-lock affected VMAs to prevent concurrent page faults. Signed-off-by: Suren Baghdasaryan Reviewed-by: Liam R. Howlett --- mm/mmap.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/mm/mmap.c b/mm/mmap.c index ec2f8d0af280..f079e5bbcd57 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -674,6 +674,9 @@ int vma_expand(struct vma_iterator *vmi, struct vm_area_struct *vma, ret = dup_anon_vma(vma, next); if (ret) return ret; + + /* Lock the VMA before removing it */ + vma_start_write(next); } init_multi_vma_prep(&vp, vma, NULL, remove_next ? next : NULL, NULL); @@ -686,6 +689,7 @@ int vma_expand(struct vma_iterator *vmi, struct vm_area_struct *vma, if (vma_iter_prealloc(vmi)) goto nomem; + vma_start_write(vma); vma_adjust_trans_huge(vma, start, end, 0); /* VMA iterator points to previous, so set to start if necessary */ if (vma_iter_addr(vmi) != start) @@ -725,6 +729,7 @@ int vma_shrink(struct vma_iterator *vmi, struct vm_area_struct *vma, if (vma_iter_prealloc(vmi)) return -ENOMEM; + vma_start_write(vma); init_vma_prep(&vp, vma); vma_adjust_trans_huge(vma, start, end, 0); vma_prepare(&vp);