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Mon, 29 Aug 2022 14:26:03 -0700 (PDT) Date: Mon, 29 Aug 2022 21:25:18 +0000 In-Reply-To: <20220829212531.3184856-1-surenb@google.com> Mime-Version: 1.0 References: <20220829212531.3184856-1-surenb@google.com> X-Mailer: git-send-email 2.37.2.672.g94769d06f0-goog Message-ID: <20220829212531.3184856-16-surenb@google.com> Subject: [RFC PATCH 15/28] mm/mmap: mark adjacent VMAs as locked if they can grow into unmapped area 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, riel@surriel.com, 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, rientjes@google.com, axelrasmussen@google.com, joelaf@google.com, minchan@google.com, surenb@google.com, kernel-team@android.com, linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, x86@kernel.org, linux-kernel@vger.kernel.org X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220829_222608_156158_C708421E X-CRM114-Status: UNSURE ( 9.35 ) X-CRM114-Notice: Please train this message. X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org While unmapping VMAs, adjacent VMAs might be able to grow into the area being unmapped. In such cases mark adjacent VMAs as locked to prevent this growth. Signed-off-by: Suren Baghdasaryan --- mm/mmap.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/mm/mmap.c b/mm/mmap.c index b0d78bdc0de0..b31cc97c2803 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -2680,10 +2680,14 @@ detach_vmas_to_be_unmapped(struct mm_struct *mm, struct vm_area_struct *vma, * VM_GROWSUP VMA. Such VMAs can change their size under * down_read(mmap_lock) and collide with the VMA we are about to unmap. */ - if (vma && (vma->vm_flags & VM_GROWSDOWN)) + if (vma && (vma->vm_flags & VM_GROWSDOWN)) { + vma_mark_locked(vma); return false; - if (prev && (prev->vm_flags & VM_GROWSUP)) + } + if (prev && (prev->vm_flags & VM_GROWSUP)) { + vma_mark_locked(prev); return false; + } return true; }